ABOUT CHVIEW The countless stars of the dark have long inspired awe. But having deduced these small lights to be radiant suns like our own, many now wonder what lies at such faraway places. For, while we have no means of fast interstellar travel today, we can dream that our descendants will. ChView is intended as a three-dimensional aid to: viewing some of the nearer stars of our galaxy; navigating the distances between them; accessing basic information (and updating what we know); and, hopefully, having some fun. Current data files provide over 7,700 stars believed to lie within 250 light-years (ly) of Earth, in a 500-ly diameter sphere. Future plans include modules for selecting a star (or multiple star system) and, based on available data and known astronomical relationships, for creating your own star system (of planets, moons, asteroids, Kuiper belt, Oort cloud/cometary halo, and even human colonies or space communities), for voyaging in faster-than-light (FTL) "starships", and the like. ChView is brought to you by Jo Grant and Ben Lin with the assistance of other subscribers of the CHERRYHLIST discussion group at jaymin@maths.tcd.ie. While some of us have been collecting star data for years, all of us are fans of the Hugo-winning author, C.J. Cherryh, who has developed an intriguing scenario for human colonization of our neighboring stars. As you may have guessed, the name "ChView" is a tribute to her. Depending on where you obtained this copy of ChView, in fact, some of the "Place Names" assigned to selected stars may be the names of Cherryh's fictional human colonies -- easily changed to suit your fancy. Copyright 1997 by Jo Grant and Ben Lin. All Rights Reserved. ChView (including all program, data, and documentation files) is the sole property of Jo Grant and Ben Lin and must not be copied or reproduced in any form without permission from one of the copyright owners, except for personal use. Comments and suggestions can be sent by e-mail to sol@nova.org. Please type "chview" in the subject line. File updates can be obtained from this Web site (http://members.nova.org/~sol/chview/) or from http://www.maths.tcd.ie/~jaymin/chview/, or by FTP from members.nova.org in the "users/sol/chview" directory or ftp.maths.tcd.ie in the "pub/jaymin/chview" directory. CONTENTS Instructions................................................... 3 The Data Files................................................. 8 About the Stars................................................ 10 Extrasolar Planets & Brown Dwarfs.............................. 14 Sol-Type Stars with Planets.................................... 14 Glossary & Formulas............................................ 15 References..................................................... 18 Appendix A - ASCII File Format................................. 20 Appendix B - Binary File Format................................ 21 INSTRUCTIONS ChView is a Microsoft(r) WINDOWS (3.1 or 95) application which runs fast with four megabytes of RAM on a 486-DX PC, which has a built-in math processor. ChView, however, has been compiled to emulate floating point calculations so that a math processor/co-processor is not needed. As regards minimal requirements, ChView has been run successfully on an old 386 -- Tandon LT laptop without a math co-processor -- with only one megabyte of RAM (384 kilobytes of extended memory). (Users of the older *.LST data files will find that the new *.CHV binary files load much faster.) The program file is called CHVIEW.EXEor CHVIEW32.EXE (32-bit version). Most users may find it convenient to copy ChView files into a new "CHVIEW" subdirectory under their WINDOWS directory (e.g., C:\WINDOWS\CHVIEW\*.*). While Microsoft WINDOWS version 3.1 or higher is needed, SMARTDRIVE (which can reserve a substantial amount of RAM memory) and EMM386 (an expanded memory manager) are not required and may be disabled by placing a remark ("REM") in front of the relevant AUTOEXEC.BAT and CONFIG.SYS statements that would otherwise run those two memory-resident programs. ChView is run from WINDOWS like any other WINDOWS-based application. For example, ChView can be operated from the WINDOWS File Manager from: "Run"; "New" ("Program Item", etc.), which brings up the ChView icon; or by selecting ChView.EXE from a display of files and directories. If you have been running an old version of ChView, you may want to rename ChView.INI (e.g., CHV-INI.OLD) to avoid potential interference with the new version of ChView, which will generate a new CHVIEW.INI file for each data file that you use. You can find the old CHVIEW.INI under the WINDOWS directory (e.g., C:\WINDOWS\CHVIEW.INI). WINDOWS-95 users may want to associate ChView with the file extension *.CHV to support execution from EXPLORER. The sphere of view is initially set for a 20-ly radius from Earth. Using "VIEW" - "PREFERENCES", one can draw links between stars based on distance. The idea is to work out and graph "best" travel routes and such. Such routes can be marked with as many four different colors as well as varying line patterns. ChView automatically subsumes "close" stars less than 0.2 ly apart. Most features of ChView are self-evident, but four instructions for mouse and keyboard are particularly important: o left-click to select a star underneath the cursor; o double left-click to bring up information on a star; o hold a Ctrl (or Shift) key down and left-click to add another star to the current selection; and o hold the right-click down and move the mouse to rotate the 3-D display. NOTE: If a newly loaded file seems to be oddly displayed, try hitting the ESC (RESET) key to enable the file's current PREFERENCE settings. Current Features: FILES: Under "FILE", "OPEN" the file desired; try the smaller data files (e.g., 25LY.CHV, CJC25LY.CHV, or CJC-ONLY.CHV) first if your computer is not a 486-DX with ample memory. A list of the files that you used most recently is displayed under the menu of FILE commands. Using FILE "IMPORT", you can load your own data files (created in ASCII as *.LST). "SAVE" allows you to save any changes as the same star file, while "SAVE AS" prompts you to record the data as a different or new file. Under "Info", you can now type in some background information on each data file that you've modified or created. FILE "EXPORT" can be used to create an ASCII data file. If a newly loaded file seems to be oddly displayed, hit the ESC (RESET) key to make sure that the new file's PREFERENCE settings are being used. ROTATING & CENTERING: Holding down the right click and moving the mouse will allow you to rotate the stellar display. Double left-clicking a star will open up options that include setting that star as the new center of display. DISPLAY RADIUS & SCOPE: The viewer can display all 7,700-some stars. Display too many stars, however, and not only does the view become a crowded mess but screen changes slow to a crawl. Hence, the initial display is set at a 20-ly radius; that is, it will only display the stars within 20 ly of your chosen center. If you move the center more than 3 pixels, though, it will recalculate the display. Under VIEW-PREFERENCES - "VIEW RADIUS", you can increase or decrease the sphere of display to the specific light-years desired. You will want to increase the VIEW RADIUS to view stars over 100 ly from Earth since the current 250 ly data files have only a sparse scattering of bright stars at that distance; in other words, the closest star to your given center star may be more than 20 ly away. EDIT "SCOPE" and the SCOPE icon give you a visual reference for the scale of display in light-years. VIEW-PREFERENCES is now also provided as an easy-to-use icon. You may need to hit the ESC (RESET) key after exiting PREFERENCES to enable the new PREFERENCE settings. GRID & DROP LINES: Under "EDIT", one can set or remove a x,y-grid with z-drop lines from each star to the grid; to see the drop lines, rotate the display with the right click. Currently, the size of each square in the grid is set to five light-years on each side. The grid also may be set to accommodate the "landscape" orientation of most PC screens ("X" distances are displayed wider than "Y" distances). You can change the settings (e.g., "X" = - "Y" scale) under VIEW-PREFERENCES "POSITION". LINKS & DISPLAY SCALE ICONS: Links can be drawn between stars that are within a set distance, and link numbers indicating distance can also be displayed. In addition, under VIEW-PREFERENCES, you can turn on or off the display of the grid and link lines and numbers. EDIT "SCALE" allows you to enlarge or shrink the distance in light-years from the chosen center currently in view. Try the icons for "ENLARGE" and "SHRINK" which are convenient to use, especially with SCOPE on. PLACE/STAR NAMES & HOVERING: Currently, only some star and place names are loaded for view to keep the display from getting too cluttered. Beyond 20 ly from Earth, only the names of larger and brighter stars (spectral-type OBAFG dwarfs, subgiants, giants, supergiants, etc.) and other celestial objects of special interest are displayed. Placing ("hovering") the cursor over any star, however, will cause its place or star name (or designation) to be displayed until you move the cursor away. You can turn off the display of names under VIEW-PREFERENCES. COLORS: The stars are colored according to their spectral type on the "main sequence", where: O is bluish violet; B is blue; A is cyan; F is pale yellow; G is yellow; K is orange; and M is red. Stars, not classed OBAFGKM, are coded X (mostly unknowns) which are initially set to grey. These color settings can be changed under VIEW-PREFERENCES - "STARS". You can also change the default background color from black to, for example, white using VIEW-PREFERENCES - "DISPLAY" - "Background". With white and other light backgrounds, you may want to change the STARS "Name Font" color to black and turn "Star Outline" on. SIZING: Under VIEW, the default display size of the stars can also be changed. Current settings are not to scale, since red giants can have diameters more than 100 times that of our sun -- 1,000 times or more for supergiants. By comparison, "white" dwarfs are of planetary scale at about the size of the Earth, or less. [A size setting has not been provided for subgiants because these stars not only pulsate (expand and contract) but their relative size would depend on their mass (initial spectral type) and stage of evolution.] If you are specifying a star that is off the "Main Sequence", you can size it under "Spectra" by adding: "d" at the beginning for white dwarfs (e.g., "dA"); "*" for giant or "~" for supergiant at the end (e.g., "K0*" or "M0~"). FAST MOVES: "GOTO", under VIEW and as an icon, is very handy for finding specific place names and stars. You can list for selection: all stars currently "In View"; only "Named" stars currently displayed; or all the named stars in the data file opened. VIEW "RESET" (or the ESC key); will return you to a predefined center. The initial center is Earth but you can specify another place under VIEW-PREFERENCES POSITION. DISTANCES: Under "REPORT", one can display and print distances from a selected star to all other stars within view. Again, ChView does not draw links between stars that are less than 0.2 ly apart. EDIT STAR SYSTEM DATA: Under EDIT, you can also edit the default data provided for individual stars (and star systems) and add new stars. Without going through EDIT, double-clicking on a star brings up a dialog box of basic information about that star. The box currently displays: Place Name; Star Name; Notes; Distance to Earth; Spectral Type ("Spectra"); Mass (as a ratio of our sun's); Constellation; and (x,y,z) Equatorial System Coordinates in light-years from Earth. There is one "button" to center the display on this star and another to edit that star's information. The "MORE" button allows you to view or add more data under "Edit Extra Data". Initially, ChView only displays data on the "brightest" star of a multiple star system, as seen from Earth. In the STAR DATA window, use the "<<<" or ">>>" buttons to view and edit data on companion stars and objects. SELECTING STARS, RUBBERBAND BOXES, & SELECTIVE DISPLAY: Left click selects the star clicked on (and deselects all others). Ctrl-Left click adds or subtracts the clicked star to a selection set. You can quickly add a group of stars to the selection set by holding down a Ctrl (or Shift) key and the left click and moving the mouse to display all stars inside a "rubberband" box, or by pointing at one star of a cluster. "CLUSTER" is enabled under REPORT. When clicking on multiple stars and adding another, ChView re-calculates the center of the selected stars. You can display or hide only selected stars by using "SHOW ONLY SELECTED" or "HIDE SELECTED" under VIEW; return to the full display by using "SHOW ALL". ADDING & DELETING: EDIT "Add Star" allows you to create a new celestial object, as well as delete ("Del Star") an existing object that has been "selected. There are three options for adding a new object: Adding celestial object between two objects: o Select two stars. o Use EDIT-Add Star to create object between two stars. Its position is at the point equidistant between the stars currently selected. Add more data and revise the equatorial system coordinates, if desired. o Adding star by entering Equatorial System Coordinates (x,y,z). o Adding object by entering known Right Ascension (RA) and Declination (Dec) and distance from Sol/Earth (Dist): Convert RA in hours (0-23), minutes (0-59), and seconds (0-59) to hour and decimals only (0-23.xxx); multiply by 15 to convert to degrees and decimals; and enter into "RA" area. Convert Dec in sign (-/+), degrees (0-90), minutes(0-59), and seconds (0-59) to degrees and decimals only (-/+ 0-90.xxx) and enter into "Dec" area. Enter distance (Dist) in light-years from Sol/Earth (e.g., <0.2). ChView will convert your positional and distance data into x,y,z coordinates using the formulas described in "Glossary and Formulas". ROUTES: Using EDIT "ROUTES" or the ROUTES icon, you can draw routes for interstellar travel (e.g., for exploration, trade, or war). Select the first star with the left click button of your mouse, then add a subsequent destination with the left click while holding the Ctrl (or Shift) key down. Use ROUTES to draw the route on the screen: choose a route type (e.g., "Route 4"), whose line type (e.g., dashed line) and color can be changed; ROUTES-"Display"; or use the ROUTES icon to switch ROUTES DISPLAY on and off. CIVILIZATION: Under EDIT, you can name a civilization, choose an origin star for interstellar colonization of neighboring stars, and set the rate and end period of colonization. Use "CIVILISATION" under REPORT to list the names of colonized stars and their order of settlement. REPORTS: The REPORT menu enables you to display and print the closest stars to a selected center star by "DISTANCE". [The reports used to offer an option for printing links between all stars in view, but this resulted in several thousand lines of information.] As mentioned previously, stars can also be clustered, and the progress of colonization by an interstellar "civilization" can also be displayed. After two stars are selected, "ROUTEFINDER" can be used to find a route of connecting stars and plot them (without displaying other stars). When you leave this command ("CLOSE"), only the stars involved in the route will be displayed; use VIEW-"SHOW ALL" to return to the original display. Using "FIND" or "FIND & REPLACE", you can search for certain terms (e.g., planets or brown dwarfs) in the Notes data section for each star system, and replace the term if desired. PRINTING: "PRINT" now works on the June 11, 1996 and later versions of ChView. Black and white print-outs can can be made very sharp by adjusting the visual display colors, under VIEW-PREFERENCES: "Background" color to white; STARS "Name Font" text color to black with a pitch size of 10 or less; and enable "Star Outline". HELP: [To be developed.] OTHER FEATURES & SETTINGS: Depending on the version of ChView that you are using, there may be other features being tested. Some other settings are currently available under VIEW-PREFERENCES (e.g., "LINK" or "NAME FONT"), but some may be dormant until other features are further developed. All ChView files (including CHVIEW.DOC) are being updated periodically. THE DATA FILES There are core four data files of increasing size from which variations have been created, including a file which provides fictional place names of significance to readers of C.J. Cherryh's works: o 25LY.CHV - about 234 celestial objects within 25.0 ly; o 50LY.CHV - about 1,387 objects within 50.0 ly; o 100LY.CHV - about 5,152 objects within 100.0 ly; o 250LY.CHV - about 7,730 objects, with most dim stars within 82 ly (25 parsecs) and most "bright stars" (-x to 6.5 apparent magnitude) within 250.9 ly; and o COLONIZE.CHV - has C.J. Cherryh's fictional place names sited at actual stars, although some stars, like the one for Russell's, may actually be the closest "jump" points to the place names. Astronomers have currently determined that at least 216 stars lie within 25 ly from Earth, in a 50 ly-diameter sphere. Geometrically, the volume of space increases roughly eight times for every doubling of the distance from Earth. Hence, assuming the same stellar density, there may be over 1,700 stars within 50 ly of the sun, roughly 14,000 within 100 ly, and roughly 110,000 within 200 ly -- 270,000 within 250 ly. Not surprisingly, comparatively few dim stars relative to their projected population have been catalogued with detailed information, perhaps due to a lesser interest among astronomers as well as the greater difficulty of observing dim objects at increasing distance. Let's assume that the 25 ly data file is reasonably complete at about 216 confirmed stars. Then, the 50 ly file (at about 1,370 stars) may have about eight-tenths of the stars that actually exist within 50 ly distance from Earth; one could safely presume that virtually all of these missing stars are M and "white" dwarfs that remain to be discovered, or assigned correct distances. At 5,100 or so stars, however, the 100 ly file has only a bit over one-third (38 percent) of the stars that should lie with a sphere of 100 ly from Earth; at this point, some G and more K stars may be missing -- particularly, in the spherical shell between 50 and 100 ly from Earth. Finally, with about 7,700 stars, the 250 ly file contains about 1/33rd (2.9 percent) of the stars that are likely to exist within that vast space -- a 500 ly-diameter sphere. Without a doubt, the more distant stars (beyond 100 ly) that have been included in the data files tend to be unusually large, luminous, and rare. Due to their extreme mass or late stage of evolution, they also have been targets of special studies by astronomers. These bright stars, moreover, are visible to the naked eye -- many with ancient names -- and can serve as guide stars ("landmarks") for imaginary voyages among the vast majority of stars too dim to be seen without a telescope. Currently, the 250 ly data file (250LY.LST) contains: 1Possible Wolf-Rayet star - Suhail (Gamma2 Velorum). 3Possible Hypergiants - CD-41 4507 and V810 and Omicron1 Centauri. 43 Possible Supergiants. 90Possible Bright Giants. 1,820 Possible Giants. 363Possible Subgiants. 5,200+ Main Sequence Dwarf stars. 15Subdwarfs. 177White Dwarfs. 10Stars with noticeable dust and/or dust disks. 18 Possible extrasolar planets (mostly gas giants) or brown dwarfs; seven confirmed since summer 1995; and one ("Goldilocks", 70 Virginis B) that lies in an orbit where water can exist in liquid form (85 degrees Centigrade at cloud top) and where carbon-based life forms may be possible. 6Nearby flare stars. 2 Stars with x-ray sources that are possible neutron-star or black- hole companions (HD 457 and BD+0 5017). Examples of all celestial objects are discussed in the "Stars" and "Glossary& Formulas" sections. Star positions are based upon Right Ascension (RA), Declination (Dec), and distance from Earth. In general, the brighter stars (everything but most M and some distant K and G dwarf stars) are based on Star Date 2000 RA and Dec positions -- accounting for Earth's precession up to the Year 2000. The position of most M stars further than 10 ly away are based on Star Date 1950 RA and Dec positions. Distances estimated using parallax measurements are less accurate for stars believed to be further away from Earth, although distances to some bright stars have been revised using other methods. Parallax measurements become particularly unreliable for stars that are beyond 200-250 ly from Earth. Data collected by the European Hipparcos satellite and currently being processed and reviewed by the astronomical community may improve future distance estimates for stars as far as 245 ly away, or 75 parsecs; public release has been scheduled for July 1997. Mass values were estimated for many stars using absolute magnitude (or luminosity) data from astronomical references. If a more precise estimate of mass is critical, users may wish to consult the latest astronomical reference with a special study on that star. ABOUT THE STARS Our galaxy, the Milky Way, contains between 100 and 400 billion (or more) stars that lie mostly in a flattened disk of some 70-100,000 light-years (ly) across with a central bulge of about 10,000 ly in diameter. Our sun, Sol, lies about 27,000 ly (roughly one half to two thirds of the way) out from the galactic center, towards Sagittarius. Sol resides within one of the spiral arms of the galaxy that is about 3,000 thousand ly thick; it is located 67 ly north of the galactic plane within a roughly 200-ly wide band that is rich in nebulae and newborn stars. From our perspective, the galactic rim is in the direction of Auriga and Taurus. Although between 5,800 and 8,000 stars are visible from Earth with the naked eye, it is seldom possible to see more than 2,500 stars at any given time from any given spot. Most of the bright stars that we see are atypical, with more mass, higher luminosity, and a greater diameter than our own sun. On the other hand, the vast majority of stars in Sol's neighborhood are dimmer than Sol, too dim to be observed with the naked eye. Although M dwarf stars constitute more than half of the population of our galaxy's stars, none are visible to the naked eye. NOMENCLATURE. Many bright stars have proper names. Most are Arabic names based upon the position of the star within the original Greek constellations -- which we refer to using Roman translations of the Greek names. Many bright stars lying within constellations have Bayer designations using the Greek alphabet (from Alpha to Omega, generally by decreasing brightness) and/or a Flamsteed number (beginning with 1, based on position in its constellation from left to right) and the genitive spelling of the Latin constellation name: for example, the star "Keid" in Eridanus is more commonly known in the United States as Omicron2 or 40 Eridani A. Stars are also designated with catalogue numbers. While some begin with the cataloger's last name (e.g., Ross, Wolf, or Chien), most use just the first letter of the name(s), or some other abbreviation, to save space. Examples: AC -Alvan Clark ADS- Aitken Double Star BS,HR- Bright Star DM: BD,CD,CP(D)- Durchmusterung FK5- Fifth Fundamental G- Giclas Gl- Gliese GJ- Gliese & Jahreiss HD- Henry Draper Kui- Kuiper L,LFT,LTT- Luyten (and others) SAO- Smithsonian Astronomical Observatory V- Variable star or Vyssotsky Wo- Wooley SPECTRAL TYPE. Astronomers differentiate the stars by spectral type, a system of classification which also indicates the star's color -- a reflection of its surface temperature. The spectral sequence of the seven basic stellar types is denoted in capital letters, which have been translated visually in ChView into colors that exaggerate their actual tint derived from surface temperature (particularly the bluish color of the hotter stars): O - bluish-violet: Iota & Zeta (Alnitak) Orionis B - blue: Algol, Regulus A - cyan: Sirius, Vega F - pale yellow: Procyon A, Eta Cassiopeia A (F9-G0) G - yellow: Sun, Alpha Centauri A K - orange: Alpha Centauri B, Epsilon Eridani M - red: Proxima Centauri, Barnard's Star Each spectral type is further subdivided into 10 divisions from 0 through 9, hottest to coolest. Most stars are of type M, with diminishing numbers up to type O -- quite rare in our galaxy. On the other hand, the average mass of main sequence dwarf stars rises dramatically from M to O. The current version of ChView consolidates stars of unknown spectral type as well as those of all other spectral types into "X". The non-OBAFGKM spectral types include reddish giants and supergiants that have become relatively rich in carbon, such as C (formerly R and N) and S types, as they have run out of hydrogen as the primary fuel for nuclear fusion -- none are currently believed to be located within 250 ly from Earth. WC (carbon-rich) and WN (nitrogen-rich) Wolf-Rayet stars such as Suhail (WC8, Gamma2 Velorum Aa) are massive stars (averaging 20 solar masses in binaries with O stars) that may have already expelled 40 percent or more of their original mass, including their entire hydrogen envelope. The extreme luminosity of Wolf-Rayets is obscured by the dust and gas shed by them. Analysis of the spectral lines found in star light yields additional information, which is noted in lower case letters following the capital letter denoting spectral type. Examples include: e - emission lines n - nebulous lines (e.g., rapid rotation) s - sharp lines k - interstellar lines (chemical compounds in interstellar dust) m - metallic lines p,pec- peculiar lines v - variable lines Some stars have a companion that is so close that they appear to be single stars. Analysis of the spectra from such stars may indicate Doppler shifts from the movements of the stellar pair, suggesting the presence of a companion star. Called spectroscopic doubles (spec.dou.) or binaries (SB), spectral lines found in their star light may be periodically doubled ("double-line" binary). If one star's spectrum is too faint to be seen, however, the spectral lines of the primary star may oscillate about a mean position ("single-line" binary). In astrometic binaries, the presence of an invisible companion is inferred from slight "wobblings" of the primary. MASS & EVOLUTION. Stars are born as collapsing nebular clouds of gas and dust in interstellar space. They become stars when nuclear fusion ignites within, as hydrogen is fused into helium. At that point, stars are said to enter the "main sequence", a time when the energy of hydrogen fusion pushes outward to balance the inward pull of gravity. Young stars in the solar neighborhood include many OBA type stars such Beta Pictoris, which is young enough to have a dust disk, as well as the double-binary system of HD 98800 which has K and M stars that may be only 10 million years old. Astrophysicists have concluded that, in order to sustain the nuclear reactions necessary to become a star, a gaseous body must have about 0.085 the mass of our sun. Currently, some astronomers have been defining a gaseous object of between 0.013 and 0.085 solar masses (about 13 to 85 Jupiter masses) as a "brown" dwarf, especially those in particularly eccentric orbits around a star since such objects probably formed at about the same time as the star from the same nebular cloud. (According to at least one theory, "super planet" in close-in orbits could be brown dwarfs or gas giants that formed after the birth of the star from a dust disk but migrated inward as the result of friction with dust or some other mechanism.) While at least one theory predicts a huge number of brown dwarfs, few discoveries were actually confirmed until recently. In 1995, however, a brown dwarf at Gliese 229 (only about 19 ly distant) was not only confirmed by the international astronomical community but also photographed by the Hubble Space Telescope; by late 1996, at least 12 were found within 250 ly of Earth -- 20 or more counting more distant objects. Most stars begin their life as "dwarfs" and spend the bulk of their lifetime in the main sequence with the same spectral type. As a star ages within the main sequence, however, it can become more as well as less luminous. Once a star moves off the main sequence, it will eventually swell so large that it's surface temperature will drop enough to shift its spectra dramatically downwards. Some large stars will shift spectral class down and back up more than once, as they shed mass and shift from core hydrogen fusion as their primary source of radiant energy. Roughly 90 percent of all dwarf stars have a mass less than that of our sun, Sol, between 0.085 (M8) and 0.8 (G8) of a "solar" mass (in theory). About 10 percent of the stars, including our sun (a G2), lie within the intermediate main sequence. While the lower limit of this range is 0.9 solar masses, the upper mass limit is uncertain, somewhere between six (B5) and 10 (B2) solar masses (in theory). Most of the stars discussed thus far will swell up and become giant stars for a period of about 20 percent of their main sequence lifetime, as they use up their hydrogen (fusing it into heavier elements or shedding it into interstellar space). Our own sun will expand from its current diameter of about 0.01 of an astronomical unit (AU) -- 1/100 of the distance from the Earth and to the sun -- to as much as one AU. Eventually, these stars will shrink into dense "white" dwarfs -- off the main sequence -- as small as, or smaller, than the Earth in diameter with between 0.5 and 1.4 solar masses. Less than one percent of all stars lie in the upper main sequence, between about eight (B3) and 120 (O3) solar masses (in theory). These stars quickly consume their hydrogen, swell up into supergiants, and may blow up in supernovae. The end result of such explosions may be a neutron star (1.4 to six solar masses) or even a black hole (over six solar masses). Small, cool, and faint M stars may last for 50 billion years or more before cooling into black dwarfs. However, the more massive a star is, the faster it consumes and sheds its mass, and the shorter it "lives" as a star. [The lifespan of a star is a function of their mass (or energy supply) and luminosity (rate of energy consumption) -- roughly proportional to 1/Mass raised to the power of 2.5.] The hottest and most massive stars may use up their hydrogen at such a pace that they last only 100,000 years, short compared with our sun's expected lifetime of about 10 billion years -- still about five billion to go. Vega, type A0, may live only one billion years; a type B star may live for 30-some million years; and the less massive O types may last as only long as three to four million years. Hence, the OBA stars observed in our skies are relatively young stars compared with redder spectral types, and any planets found around these stars are unlikely to have had the time to have evolved multi-cellular lifeforms similar to those found on Earth. Since the estimated age of our galaxy is about 13 billion years, none of the lower mass stars (M to G8) have had time to fade from view, but most of the previously born, higher mass stars (B to O) have already perished. Stars also are assigned luminosity classes: 0 - Hypergiants V810 or Omicron1 Centauri(?) Ia,b - Supergiants Antares, Canopus IIa,b - Bright Giants Dubhe, Tarazed IIIa,b - Giants Aldebaran, Arcturus IV - Subgiants Procyon A, Beta Hydri V - Main Sequence Dwarfs Sol, Sirius A sd - Subdwarfs All faint and obscure D - "White" Dwarfs Procyon B, Sirius B This classification system is perhaps a better indicator of a star's relative age and stage of evolution within its class as well as of its mass. Subdwarfs, "bluer" than "ordinary" dwarf stars, have a lower metal content -- perhaps due to their birth in an earlier age (or region) of the galaxy when relatively few supernovae had as yet spewed their metals into surrounding dust clouds. EXTRASOLAR PLANETS & BROWN DWARFS Under the constraints of current technology and analytic methods used, astronomers have not been able to confirm the detection of nearby extrasolar planets with masses less than half of Jupiter. The substellar objects described below are believed to lie within 250 light-years of Sol. Awesome visualizations of some of these objects and their star systems can can be found at John Whatmough's Web site, http://www.empire.net/~what mough/extrasolar_visions.html ("Extrasolar Visions"). Additional details on the latest discoveries can be found at Jean Schneider's site, http://www.obspm.fr/departement/darc/planets/encycl.html ("Extrasolar Planets Encyclopedia"), which provides great summaries and links to the astronomers involved. SUBSTELLARJUPITERDISTANCE Orbital Eccen-Day OBJECTSMASSESFrom Star Period tricityTemperature (AUs) (Centigrade) ------------------------------------------------------------------------ SOLAR SYSTEM Earth 0.003 1.00 1.0 year 0.017 15 Jupiter 1.000 5.20 11.9 years 0.048- 150 CONFIRMED (by mass) "Bellerophon" 0.46 0.05 4.2 days 0.00 2-3,000 (51 Pegasi B) Up. Andro. Aa1 0.6 0.95 4.6 days ... ... Rho1 Cancri B1 0.8 0.1 14.8 days ... 700 Lalande 21185 B1 0.9 9+30-50 years 0.0? ... 16 Cygni B1 1.5 0.6-2.7 2.2 years 0.67 ... 47 Urs. Maj. B 2.4 2.1 3.0 years 0.03 - 80 Tau Bootis Aa1 3.9 0.46 3.3 days ... ... "Goldilocks" 6.6 0.43116.6 days 0.40 85 (70 Virginis B) HD 114762 B 9-13+ 0.4 84.0 days 0.34 ... HD 110833 B 17 0.8 220.0 days 0.69 ... Gliese 229 B 20-5044410? years ... ... BD-4 782 B 21 0.7 240.9 days 0.28 ... HD 112758 A1 35 0.35 103.2 days 0.16 ... Xi Ur. Maj. B1 37 0.06 4.0 days 0.00 ... HD 18445 C1? 39 0.9 1.5 years 0.54 ... HD 29587 B 40 2.5 4.0 years 0.37 ... HD 140913 B 46 0.54 147.9 days 0.61 ... HD 283750 B 50 0.025 1.8 days 0.02 ... HD 89707 B 54 ... 298.2 days 0.95 ... HD 217580 B 60 ... 1.2 years 0.52 ... UNCONFIRMED (by distance from Sol) Proxima Cent. B 0.17 ... 80 days ... ... Barnard's B? 1.5 ... ... ... ... Lalande 21185B2? 1- 3+. ... ... ... Lalande 21185B3? 1? ... ... ... ... UV Ceti A1? 1.1 ... ... ... ... UV Ceti A2? 1.4 ... ... ... ... Ross 248 B? ... ... 8 years ... ... Ep. Eridani B? 3 ... 25? years ... ... 61 Cygni A1?10-80 ... 5? years ... ... 61 Cygni B1? 8 ... ... ... ... Luyten5-1668B? 60 ... 7 years ... ... AD LeonisB?30 ... ... ... ... B. Pictoris B? ...55320 years ... ... Wolf 242B 65-85 2-3 ... ... ... Rho1 CencriB2? 5 5-10 20 years ... ... CM DraconisAB1? 1- 1- 1- years ... ... ------------------------------------------------------------------------ SOL-TYPE STARS WITH PLANETS OR BROWN DWARFS SPECTRALDIA-LUMIN-METAL- PLANETTYPEMASSMETEROSITYLICITYDISTANCE ------------------------------------------------------------------------- SolG21.01.01.01.0 0 Xi Ursae Majoris F8.5 ... ... ... ... 25 47 Ursae MajorisG0-11.0-1.11.11.41.0 40-50 51 PegasiG2.50.951.41.81.2-1.5 44-65 Rho1 Cancri BG80.9......... 44? Up. Andromedae Aa? F7-8 1.2 ... ... ... 53-55 Tau Bootis Aa F6-7 1.2 1.2 ... 1+ 55-62 70 VirginisG40.9-1.01.92.90.8 55-76 HD 89707 G1 ... ... ... ... 82 16 Cygni B G2.5 ... ... ... ... 84 HD 114762 F9 ... ... ... 1- 91 HD 29587 G2 ... ... ... ... 147 HD 140913 G0 ... ... ... ... ... ------------------------------------------------------------------------- GLOSSARY & FORMULAS Absolute Visual Magnitude (Mv) and Luminosity (L): Mv = 4.8 - [2.5 * log (Lstar/Lsol)]. Absolute visual magnitude is the intrinsic brightness (luminosity) of a celestial body when viewed at a distance of 10 parsecs from Earth. The luminosity of a star is typically defined as the quantity of light (radiant energy) emitted by that celestial body relative to that radiated by Sol, our sun. Astronomical Unit (AU): Distance from Earth to the Sun, 149,598,770 kilometers (km) or about 93 million miles. Black Hole: A hypothetical celestial body of extreme density whose gravitational strength is great enough -- within a certain distance dependent on its mass -- to prevent the escape of light (i.e., photons). In theory, black holes that result from the collapse of very large stars should have over six solar masses. Matter falling into black holes may emit detectable x-rays; two x-ray sources in the star files are HD 457 and BD+0 5017 (68 and 56 light-years from Earth, respectively). Distance Modulus: Mv - M = 5 - [5 * log d], where Mv is absolute visual magnitude, M is apparent magnitude (the apparent visual brightness of a celestial body without adjusting for distance from Earth), and d is distance in parsecs from Earth. Dust, Stellar Disks: In recent years, astronomers have been able to detect enormous disks of dust around some stars, especially young T-Tauri types. Some young, local stars with substantial dust include Beta Pictoris, Fomalhaut, and Vega. At least one astronomer may have detected gaps within the inner dust disk of Beta Pictoris, possible evidence of planetary formation. Dust has also been detected around Epsilon Eridani, Ross 128, 61 Cygni2, and Tau Ceti. Equatorial System Coordinates (x,y,z): In light-years (d) from Sol, using right ascension (RA) converted from hours to degrees (multiply by 15) and declination (Dec) in degrees. Trigonometic functions in Lotus and Quattro Pro spreadsheets require that degrees be converted to radians by multiplying by (@Pi/180). x = d * Cosine(RA*15) * Cosine(Dec); y = d * Sine(RA*15) * Cosine(Dec); and z = d * Sine(Dec). Flare Stars (UV Ceti type): Some low mass (M or K) dwarfs can "flare" suddenly and enormously (compared with our own sun's puny "solar" flares), brightening the star from one to six magnitudes and lasting for several minutes (e.g., UV Ceti B, Luyten 726-8 B, Kruger 60 B, Ross 154, or Proxima Centauri). Lifetime, Stellar: Lifetime = (Solar lifetime = 10 billion years) * [(1 / solar masses) raised to 2.5 power)] M7-8 = (10) * [(1/0.1)^2.5)] = 10 * 316 = 3.2 trillion years M0 = 0.5 = 5.7 = 57 billion years K0 =0.7 = 2.4 = 24 billion years Sol(G2) = 1.0 = 1.0 = 10 billion years F-class = 1.3 = 0.52 = 5.2 billion years A-class = 2.5 = 0.10 = 1.0 billion years B-class = 10 = 0.0032 = 32 million years O-class = 25 = 0.00032 = 3.2 million years O3 = 120 = 0.00006 = 63 thousand years Light-Year: 9.4 trillion km, almost six trillion miles, or 0.3066 parsecs. Luminosity (L) and Mass (m): O - K2: Lstar/Lsol = [m(star)/m(sol)] to 4th power. K5 - M5: Lstar/Lsol = 0.6 * {[m(star)/m(sol)] squared}. Magnitude: A number representing the intrinsic or apparent brightness of a celestial body on a logarithmic scale, in which a difference of one unit corresponds to the multiplication or division of the brightness of light by 2.512. Neutron Star: A super dense, stellar remnant of between 1.4 and six solar masses and of small, asteroid-like size (e.g., a mile in diameter) that: may result from the supernova explosion of a very large star; is composed of closely packed nuclear particles (primarily neutrons); and may be detectable through the emission of X rays. Two x-ray sources in the star files are HD 457 and BD+0 5017 (68 and 56 light-years from Earth, respectively). Parsec: 3.2616 light-years; the distance at which the Earth's orbital radius would subtend an angle of one second of arc. Speed of Light: 299,792.458 km/second or over 186 thousand miles/second. Spectroscopic Doubles: The stars in these binary systems are so close together that only analysis of the spectra of their light (resulting in spectral lines that are doubled and/or that oscillate) reveals their binary nature (e.g., Groombridge 34 A or Algol). Variables, Eclipsing: Also known as "eclipsing binaries", changes in the apparent brightness of these stars are caused by one star of the binary system passing in front of the other -- relative to an observer on Earth. Some are at maximum brightness most of the time (Algol type, EA). Others involve stars that are so close together that their shapes are distorted into two "eggs" in near physical contact; of these, dwarf pairs may have periods of less than one day (W Ursae Majoris type, EW), while others exhibit continuous light-variations that alternate in length between short and long (Beta Lyrae, EB). Variables, Pulsating: Some stars actually expand and contract in size over time (months to seconds), which changes their brightness. Many such stars (Mira, semi-regular, Cepheids, RR Lyrae, RV Tauri, Beta Canis Majoris or Beta Cephei, Alpha Cygni and irregular types) are evolving off the main sequence, and thus include many subgiant, giant, and supergiant stars that are exhausting their core supply of hydrogen and fusing heavier elements in concentric gaseous shells. Delta Scuti type (which have small amplitudes and periods from 0.02 to 0.25 of a day) are young A and F stars, and many are spectroscopic binaries; subdwarfs of this type are call SX Phoenicis stars. ZZ Ceti type are white dwarfs with small amplitudes and periods as short as 30 seconds. Variables, Eruptive: These stars include novae and dwarf novae, flare stars, nova-like, P Cygni, nebular, and R Coronae Borealis variables. Variables, Rotating: Exhibiting small amplitudes, variations in brightness may be due to non-uniform surface brightness, fast rotation and great chromospheric activity, and binaries where one companion is rapidly rotating and large (FGK giant or subgiant) or where the stars are very close and gravitationally distorted (ellipsoidal variables). Variables, Secular: Stars such as Beta Leonis, Theta Eridani, and Delta Ursae Majoris may have brightened or faded over historical time periods. These "estimated" variations, however, are generally thought to be suspect, due to the subjectiveness of eye-ball observation in less technological times. * * * o WINDOWS and EXPLORER are trademarks of the Microsoft(r) Corporation. o 1-2-3 is a trademark of IBM(r), the International Business Machines Corporation. REFERENCES MACHINE-READABLE DATA: Two good Web sites to get machine-readable star data and other astronomical catalogs are: o http://nssdc.gsfc.nasa.gov (also accessible by anonymous ftp) o http://cdsweb.u-strasg.fr/htbin/myqcat3?V/70A/. Look for data from: Gliese, W. and Jahreiss, H., "Preliminary Version of the Third Catalogue of Nearby Stars" (Heidelberg, Germany: Astronomisches Rechen-Institut, 1991). [From CDSWEB at the University of Strasbourg, France.] Hoffleit, Dorrit, "Preliminary Version of the Bright Star Catalogue, 5th Revised Edition," (New Haven, CT: Yale University, 1991). [From the National Space Science Data Center (NSSDC), USA.] Ochsenbein, F., Acker, A., Legrand, E., Poncelet, J.M., and Thuet-Fleck E., "Catalogue des etoiles les plus brillantes", edited by Acker, A. (Strasbourg, France: Observatoire de Strasbourg, Centre de Donnees Stellaires et Planetarium de Strasbourg, 1984). Revised and compiled by F. Ochsenbein and J.L. Halbwachs, Stellar Data Center, Strasbourg Observatory, France. [Also available from NSSDC, USA.] Woolley, R., Epps., E.A., Penston, M.J., and Pocock, S.B. 1970, "Catalogue of Stars within 25 Parsecs of the Sun", _Royal [Greenwich] Observatory Annual_ (No. 5). [From NSSDC, USA.] PRINT Consulting other astronomical references (e.g., books) may be most convenient for additional details on specific stars, such as proper names, evidence of dust, brown dwarf or planetary companions, unusual flaring, variable brightening/stellar swelling, constellation, and other specific features. Beatty, J. Kelly, O'Leary, Brian, and Chaikan, Andrew, eds., _The New Solar System_ (Cambridge, MA: Sky Publishing Corp., 1981). Burnham, Robert, Jr., _Burnham's Celestial Handbook_ (Mineola, NY: Dover, 1978). Consolmagno, Guy J., and Schaefer, Martha W., _Worlds Apart: A Textbook in Planetary Sciences_ (Englewood Cliffs, NJ: Prentice Hall, 1994). de la Cotardiere, Phillippe, _Larousse Astronomy_ (New York: Facts on File, 1987). Dickinson, Terence, _The Universe ... and Beyond_ (Buffalo, NY: Camden House Publishing, 1992). Flammarion, Camille, _The Flammarion Book of Astronomy_ (New York: Simon & Schuster, 1964). Hartmann, William R., and Miller, Ron, _Cycles of Fire_ (New York: Workman Publishing, 1987). Kaler, James B., _Stars_ (New York: Scientific American Library, 1992). Mallove, Eugene, and Matloff, Gregory, "Appendix 3: Nearby Star Systems", _The Starflight Handbook_ (New York: John Wiley & Sons, 1989). Moore, Patrick, _The Guinness Book of Astronomy_ (Middlesex, UK: Guiness Publishing, Ltd., 1988). ______________, _Patrick Moore's A-Z of Astronomy_ (New York: W.W. Norton & Company, 1987). Menzel, Donald, and Pasachoff, Jay, _Peterson's Guide to the Stars_, "Appendix 2: The Brightest Stars, to Magnitude 3.5" [Extracted from _Sky Catalogue 2000.0_, Vol. 1, by Alan Hirshfeld, Roger W. Sinnot, and Francois Ochsenbein (Cambridge, MA: Sky Publishing Corp., 1991).], and "Appendix 4: The Nearest Stars". APPENDIX A ASCII File Format (*.LST) o You can create your own ASCII data files using a spreadsheet (e.g., Lotus 1-2-3(r) and printing to a file, with a name that ends in a *.LST suffix. Use FILE IMPORT to use the file, and "SAVE AS" to create a *.CHV binary file. o The following fields are separated by "/": -Place Name; -Star Name; -Distance to Earth in light-years; -Spectral Type; -Mass (as a ratio of our sun's); -Constellation; -Notes; and -(x,y,z) Equatorial System Coordinates in light-years from Earth. o Each line is a record of field data on a star, or some other celestial object. oExample: Earth/Sol/0.00/G2/1.00/(no constellation)/Sun, 9planets/0.00/0.00/0.00 o In a spreadsheet, you will establish columns of a certain width. Printing to a file will result in unnecessary blank spaces within fields. Moreover, printing to an ascii file may result in blank lines between groups of records. While the initial FILE-IMPORT of such an *.LST file will be relatively slow, FILE-SAVE it using ChView as an *.LST file and the blanks will be removed, speeding up file uploading. o FILE-SAVE your *.LST file using SAVE AS *.CHV to gain even more efficiency in file loading and to enable and save certain features of ChView (e.g., routes) that require a binary data structure. o Refer to the INSTRUCTIONS and GLOSSARY above for more specific details (e.g., using ChView features, sizing stars, or spectral types. APPENDIX B Binary File Format (*.CHV) As the internal format of ChView is object based, the data file is comprised of serialised objects. Each fundamental data type has its own representation on disk. Integers: are saved as 2 byte bitfields. Longs: are saved as 4 byte bitfields. Strings: are saved a a 1 byte length determinator followed by that many bytes of data. This does not include the null terminator. If the string is longer that 254 then a byte containing FF is stored with two bytes following containing the actual length. Floats: are unusual. They are stored as string representations. This is done because most of the floating point numbers we wish to store are nice rounded numbers. It is more efficient to store them as strings than 8-byte floating point values. Colorref: this is a Windows RGB value. It is promoted to a long and saved as that. LogFont: a binary representation of the Windows structure. Preamble: This area stores overall information for the data file. First is stored a long value containing the version number of the data representation. The current representation is version 00000101 (hex value). Future versions will increment this number. Next are the view preferences: Grid |int |Display grid or not GridSize |double |Granularity of grid Link |int |Display Links or not LinkNumbers |int |Display Link Numbers or not LinkSize x 4 |double |Size of each link gradation StarName |int |Display Star Names or not Radius |double |View Radius Scale |int |Display Scope or note GridStyle |int |Style of grid lines LinkStyle x 3 |int |Style of link lines StemStyle |int |Style of stems StarOutline |int |Display star outline or not RouteDisp |int |Display routes or not Dummy x 8 |long |Reserved OColour |Colorref |Colour of spectral type O stars BColour |Colorref | AColour |Colorref | FColour |Colorref | GColour |Colorref | KColour |Colorref | MColour |Colorref | XColour |Colorref | BackColour |Colorref |Colour of background TextColour |Colorref |Colour of text LinkNumColour |Colorref |Colour of link numbers LinkColour x 3 |Colorref |Colour of link gradations GridColour |Colorref |Colour of grid StemColour |Colorref |Colour of stems ORad |int |Radius of spectral class O stars BRad |int | ARad |int | FRad |int | GRad |int | KRad |int | MRad |int | XRad |int | DwarfRad |int | GiantRad |int | SuperGiantRad |int | CentreOrds x 3 |double |Galactic coordinates of centre theta |double |Rotational position phi |double | rho |double | tscale |double |Angular scales pscale |double | rscale |double | xscale |double |Display scales yscale |double | GroupLabel x 4 |string |Names of groups DisplayGroup x 4 |int |Display each group or not RouteLabel \ |string |Name of Route label RouteColour x 4 |colorref |Colour of Route RouteStyle / |int |Style of Route lines LinkF |logfont |Link Number font NameF |logfont |StarName font UNameF |logfont |Unused font Data: First here is a long containing the number of star objects that follow. Each object consists of: cjcName |string |Proper Name of Place starName |string |Official name of star dToEarth |double |Distance to earth Spectra |string |Spectra Mass |double |Collapsed mass ActualMass |double |Uncollapsed mass ords[0] |double |Galactic coordinates ords[1] |double | ords[2] |double | Constellation |string |Constellation Comment |string |Comment Selected |int |Selected or not index |int |Index in file Group |int |Group of star There is a single byte indicating if there is a subsidiary star orbiting this one. If so this entire data structure repeats (recursively). Lastly we record the links. First is a integer value indicating the number of following links. Each link is then represented by a integer containing the type of link and a string containing the starName of the destination. Postamble: This contains only a string giving general comments on the entire file.