IceAceTom

12/05/2014

2298

This is a single .zip file containing the main files from my "Space" series of AstroSyn star data filesets, and covers a distance of 100 light years from the Sun. The original files were uploaded in 2010 over a period of several weeks, and I never thought to combine them into one zip. Well, better late then never! :-) Nothing has been changed, though I did some minor renaming of the files to make them more descriptive.

It's only out to 100 ly since that was my first phase target distance. I had planned to continue past 100 ly, but the number of stars begins to rapidly increase the farther out you go (this becomes apparent even at 90 ly), and I needed a break. I didn't just copy data from the Hipparcos catalog, I researched each and every star (using various sources as noted below) to compare the data and selected what I thought was the most "correct" or best-fitting. That took a long time, especially when it came to oddball stars (like sub-dwarfs and sub-giants) and complicated multiples, not to mention the swarm of red dwarfs that are out there (that's why I cut out most of the smallest ones). I do intend to continue this project, when I can find the time to spend on it.

Ok, this .zip contains the following files:

* Five .csv files in the AstroSynthesis format for importing into the program. One file covers just about every star out to 20 light years from Sun, except for solo brown dwarfs discovered since 2010 and maybe the odd faint red dwarf. The other four files cover the distance from 20 to 100 ly in four distance shells: 20-60 ly, 60-78 ly, 78-90 ly and 90-100 ly. I split them like that to keep them of manageable size, and each has roughly the same number of records. They have a nominal absolute magnitude limit of 9.50, though there are exceptions, mainly HabCat red dwarfs and red/white dwarfs that are part of a multiple system; some other solo red dwarfs fainter than 9.50 also were included. The only stars left out were a multitude of the faintest red dwarfs and some white dwarfs. Those weren't too important for the purposes of this project.

* Five corresponding "Data" spreadsheet files, in both Excel (.xls) and OpenOffice (.ods) format. They were originally created using the OpenOffice spreadsheet (hey, it's free!), but I saved them in Excel format for convenience. These spreadsheets have no formulas included, they are the final results, basically the "raw" data that was used to create the AstroSyn .csv files. I include them so you can use the data for your own purposes.

* Finally, two AstroSyn SECTOR files (they were created using version 2). One goes out to 20 ly, and the other goes to 100 ly--all the files combined. They include galactic "compass" headings to keep you oriented.

The thumbnail above shows a close-up of part the area around Sol, looking slightly away from Coreward; double stars Alpha Centauri, 36 and 70 Ophiuchi (selected) are shown, plus some others (multiple stars are green in the included sector map).

What follows is the description of this project:


This is a project that combines 3-D mapping of "Real Space" using AstroSynthesis with an experiment of mine in creating a science fiction universe. The AstroSyn .csv files are not just a simple data dump of a star catalog, but essentially a database, with a whole lot of stellar data, both given and calculated. Two key things of this project are that multiple stars are formatted properly for AstroSyn, and that I preserved the standard heliocentric galactic coordinates in AstroSyn's non-standard method.

This is intended for fictional endeavors, not real-world use, as I have not strictly adhered to reality when making this dataset. I wanted plausibly realistic stellar data to build a universe upon, so while things like star names, distances and catalog numbers are the real ones, I calculated my own spectral classes and masses, standardized into fixed ranges, i.e. I've "binned" them, and from that everything else was derived.

For the most part, my calculated spectral classes are in close agreement with given values, at most deviating by one or two subdivisions, e.g. a K0 might become a G9, an M0 a K9, and so on. The stellar masses though most likely vary from reality by a larger amount, mainly because reality has many variables, but the ones I calculated do seem reasonable, and I wanted to simplify things and have a smooth progression in the masses in relation to spectral type, at least for dwarf stars (luminosity class "V"; our Sun is a G2V star). Non-dwarf stars and oddballs were given a custom mass, usually similiar to the real one.

Another deviation from reality is with the wide double stars, those with components separated by more than 1,000 A.U.s or so. I broke down those doubles into individual stars for use in AstroSyn, and adjusted the parallax of the "B" (or "C" in some cases) to make it far enough away from its companion so it would be distinct in AstroSyn's display. As such they are farther apart than in reality.

Other variations from reality are due to creative license, this dataset is also meant to be the basis for a SF universe after all, so I've definitely fictionalized some things when it comes to habitability. The HabCat dataset has a large number of red dwarfs, especially within 100 light years of earth, and I wanted far more of G- and upper K-type dwarfs. So I ignored things like metallicity (heavy element) content and if the star's age was too young. More binary systems were included as well if they were the least bit plausible. These things can be changed to suit your needs if you wish.

I did however eliminate any star of spectral class F4 and higher, as well as giants, from habitability or planet consideration (this applies much more to the stars beyond 20 light years). It would be too big of a deviation from reality to be believable otherwise.

The AstroSyn Notes section for each star has been preloaded with loads of data, such as distance in ly, various catalog numbers, a standardized mass and luminosity, habitable zone distance (using a custom bolometric luminosity correction), the orbital period of a planet at that HZ and the tidal force exerted on that planet (so you can tell if you'll have a tidally-locked rotation period, though as with our own Mercury, that isn't always the case, and in fact you can set it up so even a habitable planet around a red dwarf isn't tidally locked, thus keeping one side from broiling and the other freezing).

Multiple star systems are also broken down and formatted for proper display in AstroSyn. Standard heliocentric galactic coordinates are also converted to AstroSyn's format (AstroSyn's X axisis the same as Xg, AstroSyn's Y axis is Zg, and AstroSyn's Z is the negative Yg).

Sources Used:

* Number one is Winchell Chung's 3-D Starmaps website www.projectrho.com/public_html/starmaps/index.php Loads of great information and links there, like the formulas to calculate galactic coordinates. Many thanks to this site!

Primary data sources:

* David Nash's HYG Database astronexus.com/node/34

* The HabCat dataset from scientists Jill Tarter and Margaret Turnbull www.projectrho.com/public_html/starmaps/catalog...

Websites:

* The Internet Stellar Database www.stellar-database.com/

* SolStation's Notable Nearby Stars www.solstation.com/stars.htm

* Atlas Of The Universe www.atlasoftheuniverse.com/

* ARICNS (the custodians of the Gliese Catalog) wwwadd.zah.uni-heidelberg.de/datenbanken/aricns/

* RECONS www.recons.org/

* SIMBAD Astronomical Database simbad.u-strasbg.fr/simbad/

* James Kaler's Stars site at the Univ. of Illinois stars.astro.illinois.edu/sow/sowlist.html

* I also used the free Stellarium software and some books I have.

I used the websites and books to weed out errors from the HYG Database and to find the most "correct" or best-fitting data.

Oh, if you're not familiar with the HabCat, it's a subset of the Hipparcos catalog, with those stars out to a certain distance that are capable of hosting an advance sentient civilization, according to the authors' criteria. So these are stars that are old enough, single or are part of a wide binary, stable, and have a metal content ("metal" being all elements heavier than helium) high enough to have terrestial-type planets; there are lots of other factors involved too. Surprisingly, a large number of red dwarfs are included. Some of the stars in the HabCat already have had planets detected around them. So if you want to stay true to scientific accuracy when making habitable planets in a fictional universe, you'll only use the HabCat stars. I find that too limiting for my purposes, as I want a large number of the smaller F, all G and the larger K-type stars to potentially have earth-like planets, and never mind reality (like Alpha Centauri A *and* B; they aren't in the HabCat but I think it's just plausible enough to have a single habitable planet around each).

The HabCat stars in the data files are labelled as such in the "CAT TYPE" data column; the "PlusCat" stars are my "additions". Most of those stars make up my "Tier 1" in the data files. Stars labelled as "NHC" are "Non HabCat", being not members of the actual HabCat or my "PlusCat".

Following are some notes on the other data columns in the spreadsheet files. The formulas I used came from Stephen L. Gillett's book "World-Building: A writer's guide to constructing star systems and life-supporting planets", part of the Science Fiction Writing Series edited by Ben Bova. It's a great book, not too complex, and Gillett's opinion is that red dwarfs CAN support habitable planets. They may not be common, but are not impossible.

"Hab" is the Habitability type, "1" means the star is in the HabCat dataset, "+" is my own "Pluscat" additions to the HabCat, "-" is for everything else, generally non-habitable (NonHabCat) or unusable. An "M" indicates a multiple star system, with a lone "M" being in HabCat, "M+" a PlusCat system, "M-" a NonHabCat. It corresponds to the "Multiple" type in AstroSyn.

"Mult" is for sorting components of a multiple star system; "M0" is the base level for "normal" binaries/multiples, "M1", "M2", "M3" and so on are for the individual components. An "S" at the end indicates a spectroscopic binary. "W1", "W2", "W3" and so on are for components of a wide multiple/common proper motion pair, they are treated as individual stars. An "MS" means a single spectroscopic binary whose components are so close that they are combined into one.

"Display Name" is what's used in AstroSyn's display; this is usually what the star is most known as or called, which could be a proper name (only if commonly used, obscure ones were ignored in favor of more familiar designations), Bayer letter, Flamsteed number or other primary catalog number (for example, many variable stars use their variable star catalog designation, like DX Cancri).

"Gliese" is the is the Gliese catalog number, includes GL, GJ and sometimes Wo. In some cases I left the old "NN" designation in place.

"Spect2" is my derived/calculated spectral class, done by looking up the absolute magnitude in a table of fixed mass ranges; "w" indicates a white dwarf, and for the odd subdwarf, an "E" is used instead of "VI" to indicate the equivalent spectral type if the star wasn't a subdwarf.

"V" is given visual magnitude, using the best-fitting value I found.

"B-V" is the given B-V value, again whatever fit best though sometimes I modified it to suit my purposes.

"M" is calculated absolute magnitude, using the standard formula.

"Mass" is my calculated mass value. It incorporates a built-in bolometric correction for class "V" stars of G8 and lower. For Non-dwarf stars and other oddballs I manually inserted a value that came close to reality.

"Dist LY" is the calculated distance from the Sun in light years, using the best and most precise parallaxes available; these were usually from the HYG catalog, but for the nearer stars I also used ones from the RECONS website.

"CAT TYPE" is the HabCat/PlusCat/NHC type described above; "MPL" means a multiple star. This is used for searches in AstroSyn.

"Tier" is my calculated Tier, looked up in a table. It's based on the parameters of my SF universe, and is also used for searches in AstroSyn, as well as for determining display color. It's what I use to group stars according to value and desirability; Tier 1 is the best group, while red dwarfs are divided into two sub-groups under Tier 4. "N" in the Tier designation means a star not capable of hosting a habitable planet, i.e a "NHC" cat type and not one of the HabCat or my PlusCat stars.

"Tag" is a special identifier for some stars, like very old ones (OLD; sub-giants mainly); true giant stars (G); UV Ceti-type variable stars of note (UVC); sub-dwarfs (SD), "superflares" (SF, some G-type dwarf stars are known to experience the occasional extremely massive solar flare, the kind that would sterilize the earth if our sun were to have one), some multiple stars whose components are of similiar brightness, increasing the combined magnitude (MB), and very close binaries whose components are close enough together that a planet can orbit both of them (CB).

"Plan" is for whatever planets that have been detected around the star, indicated by a "P" followed by a number. In some cases I ignored reality, like for "torch Jupiters" that I deemed irrelevant. It also doesn't reflect recent discoveries, you can add them if you wish. A "B" indicates a brown dwarf companion "planet", and "DD" means a dust (or debris) disk, such as those discovered around Beta Pictoris and Vega.

Following the "Plan" column are the alternate name and four different catalog numbers under which the star is known, if there are any; they are the Hipparcos, HD (Henry Draper), HR (Hoffleit Bright Star) and BD (Bonner Durchmusterung) catalogs.

"LUM V" and "LUM B" are calculated visual and bolometric luminosties. The visual one used the standard formula; the bolometric one used my own custom bolometric correction value, based on my best estimates. The bolometric luminosity is important when dealing with K-type stars and red dwarfs, since as stars get smaller in mass they output a larger portion of their energy as infrared radiation--need to take it into account when ceating a planet around a small-mass star.

"RA" and "DEC" are right ascension and declination coordinates (epoch 2000.0) of the star in DMS format.

The next four data columns are the calculated bolometric habitable zone (it's the "center line" distance, where the solar equivaent energy output is found) in astronomical units (B HZ), the orbital period of a planet at that distance both in years and days(Per @ HZ), and the tidal force exerted on a planet at the HZ distance

The last three columns are the calculated standard heliocentric galactic coordinates. As noted above, these differ slightly from what AstroSyn uses; a simple conversion was done when the AstroSyn .csv file was created.

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Thanks to all who've downloaded this file and the older ones.

My email is iceagehiker@yahoo.com

--Tom