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I am looking for a particular set of information to essentially make a star map for a game.

What I need:

  • All stars within 11,462 light years of Earth.
  • Their stellar classification.
  • If they have any planets around them (hypothetical or otherwise)
  • Their position using an x, y, z coordinate relative to earth or galaxy center (I don't really get declination, etc)

I need the extrapolated position/distance data, not the catalogs themselves.

The best one I can find is HYG, HabCat, and HYGHag is limited to to like 120,000 of 1,2 billion estimated stars... Are there any better?

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  • $\begingroup$ Are you sure that you want a volume-limited catalog ("all stars within X light years"), and not a flux-limited catalog ("all stars which appear brighter than X as seen from Earth") ? Google for the Hipparcos catalog to get 3D positions of brighter stars. $\endgroup$
    – mtewes
    Sep 2, 2016 at 9:19
  • $\begingroup$ All is what I "want"... Cuz I like to keep as close to "reality" as possible, but minimally I need all stars within 100ly of Earth for anothe reason too. $\endgroup$
    – Durakken
    Sep 2, 2016 at 9:28
  • $\begingroup$ This is going to be a lot of work on your part to compile something like this. All this information, in this format, is not going to be compiled easily. Likely you'll need to use several sources and do a lot of converting. A good place to get exoplanet data is exoplanet.eu where you can download all their data. However, it will require significant work to match up their star names with stars from other catalogues. Often a single star will have many different names, depending on what catalogue its in. $\endgroup$
    – zephyr
    Sep 2, 2016 at 12:53
  • $\begingroup$ FYI, I'm not sure if you know, but the general naming format for exoplanets is STAR_NAME X where X is some lower-case letter starting at b for the closest planet to the star and proceeding alphabetically for every planet thereafter. An example would be HD 1160 b which is the closest planet around the star HD 1160 (the HD referencing the Henry Draper Catalogue). $\endgroup$
    – zephyr
    Sep 2, 2016 at 12:58
  • $\begingroup$ @zephyr Yes I knew that. Though thanks ^.^ The exoplanet database looks nice $\endgroup$
    – Durakken
    Sep 3, 2016 at 4:33

2 Answers 2

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Best chance would be the Hipparcos catalogue. The first set of Gaia data will be released Mid-September 2016, but I don't know if it will be more accurate than Hipparcos already.

All stars within 11,462 light years of Earth.

That won't be easy. These catalogues have a magnitude (brightness) cutoff. Brighter, more massive stars can be seen further away than smaller, darker ones.

Their stellar classification.

Spectral type should be in there.

If they have any planets around them (hypothetical or otherwise)

Searching for Exoplanets is an ongoing project, and there is no complete catalogue in any sense of the word yet for any radius. Most Exoplanets were found with the Kepler mission, but that one looked in a fairly small part of the sky. What exactly do you mean by hypothetical planets?

Their position using an x, y, z coordinate relative to earth or galaxy center (I don't really get declination, etc)

You'll have to convert that yourself. If you know how to program, there are libraries for coordinate conversion. I would argue, though, that an Earth-centred spherical coordinate system is preferential for most applications.

Distances are hard to measure. Hipparcos and Gaia use the parallax method. This gets less accurate with increasing distance. Also, distances are naturally measured in parsec, but the conversion to light years is trivial.

The Gaia catalogue will have $10^9$ stars with positions and velocities. It will also be more accurate than Hipparcos. But the measurements are ongoing, and the final data release is planned for 2022.

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  • $\begingroup$ Isn't there a compendium/compilation catalog? That while one catalog might not have it another does so it's all included in 1 catalog or no? What I mean with the planets is that I'm going to have to generate the majority of those anyways, but if there are possible planets there if it's noted I'd find it useful to have it there to see what it's saying a star has. As to the coordinate system... it doesn't hurt to ask ^.^ I hate that system, but yeah I'm going to have to convert anyways, I was just hoping not to have to figure that out too. $\endgroup$
    – Durakken
    Sep 2, 2016 at 9:34
  • $\begingroup$ As far as lightyear vs parsec that's fine... I consider both bleh measures outside of average human practical use ^.^ I have my own unit that is equivalent to 24 Terameters so technically if they measured in terameters that would be ideal for me ^.^ ---- Also is there a rough guess at how many stars are in that volume? I need to know that to know how many I need to generate, even with a catalog. $\endgroup$
    – Durakken
    Sep 2, 2016 at 9:37
  • $\begingroup$ @Durakken: Well, length conversion is simple, and Parsec is what the actual measurement is, so that's what's used. As for a compendium catalogue of stars and planets, to my knowledge there isn't one. When the Hipparcos catalogue was made, there were no / very few exoplanets. Also, it's mostly used by people interested in stellar evolution and galactic dynamics, and these people don't need planets. Exoplanet researchers are better off with a specialized catalogue that doesn't consist of 99.x% irrelevant entries. Best chance is to find an exoplanet catalogue and match positions with Hipparcos. $\endgroup$
    – Alex
    Sep 2, 2016 at 9:53
  • $\begingroup$ To find sunlike stars at that distance, abs mag 4.83, your catalog will need a cutoff of at least magnitude 17.6. A decent calculator: calctool.org/CALC/phys/astronomy/star_magnitude You might be able to find suns that far out in a catalog, if not hidden behind nebula, but you're going to have to just make up the distant K and M type star locations. $\endgroup$ Sep 2, 2016 at 13:28
  • $\begingroup$ Well dl the HIP and Tycho Catalog... They're useless to me. i need the position data calculated out, not the arc seconds and such cuz I don't understand the math to get the position out of that... $\endgroup$
    – Durakken
    Sep 3, 2016 at 4:13
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Okay, so...this was useful info to have for me too, so I went and mined the TGAS database for the info, and linked to it at the bottom of this post. Stellar Classification and potential exoplanets aren't in that database, but I put together a spreadsheet that has the x,y,z coordinates (based on a 0,0,0 at Earth). Unfortunately, it's too large to include here as a list, it's 2 full Excel files, and together they keep trying to break my computer (lots of data), but...if you're still looking...

Here's a (very) small sample (distance is calculated using the basic parallax formula, not the more precise tan p parallax formula):

random_index    ref_epoch   x   y   z       hip tycho2_id   solution_id source_id   ra  dec parallax (microarcseconds)  pmra    pmdec   l   b   ecl_lon ecl_lat distance
1891830 2015    -1.175720959    1.17086547  11.74409309     1475        1.64E+18    3.85E+17    4.61210931  44.02467259 280.740075  2890.430683 411.3193209 116.6897371 -18.44687044    24.68933841 37.92446897 11.75464529
1857057 2015    2.09652758  -4.931871156    5.090024277     105090      1.64E+18    6.58E+18    319.296181  -38.87213809    251.1381922 -3259.357807    -1145.976397    3.896955138 -44.24314653    309.5200941 -21.95229864    13.14017582
311197  2015    10.41485921 3.064847483 10.64996366     86162       1.64E+18    1.64E+18    264.1042933 68.33385029 220.0247581 -320.7194666    -1269.760347    98.59630954 31.96601662 139.2005583 87.12847735 14.99831214
760193  2015    1.251151806 7.539600873 -1.988392949        113020      1.64E+18    2.60E+18    343.3238365 -14.26650242    214.0513327 957.9326981 -673.6327878    52.0031509  -59.63494581    339.1718482 -6.630784729    15.41686267
1000243 2015    -5.030975232    -3.085269521    5.125922899     106440      1.64E+18    6.56E+18    323.3912714 -49.01240356    201.1182908 -46.04495411    -816.3335416    349.1682918 -46.34874506    308.617526  -32.47800551    16.408254
1082118 2015    -5.985285182    6.484718005 -15.94185626        25878       1.64E+18    3.21E+18    82.86732881 -3.685946485    177.0825728 761.5607778 -2092.422267    206.9444274 -19.44877321    82.01126856 -26.92764376    18.63537415
1570537 2015    -9.766742012    9.115241647 16.31508852     96100       1.64E+18    2.26E+18    293.0971203 69.65393397 173.6006956 597.4820173 -1738.313483    101.2968418 21.87221014 30.24612371 80.9156096  19.00914042
1028540 2015    0.632688268 0.63719125  -18.96693027        29295       1.64E+18    2.94E+18    92.64361965 -21.86762367    172.6613419 -136.4435268    -714.8757906    228.6149634 -18.4408549 93.48733986 -45.27490715    19.11255851
200432  2015    -9.631455176    -9.709545264    -14.35380391        117473      1.64E+18    2.74E+18    357.3063278 2.39718711  169.0924333 992.5177372 -968.5413364    93.56722779 -56.88503386    358.4823087 3.270653435 19.51595311
516212  2015    -2.374861856    -5.965410295    7.703383044     99701       1.64E+18    6.67E+18    303.4770841 -45.16468615    162.2350878 778.2400404 -159.8267172    354.8063699 -32.97804057    295.3299798 -24.62550106    20.34085255
1426795 2015    4.678437114 -4.563066555    20.71229801     71253       1.64E+18    6.32E+18    218.5685329 -12.51708873    159.1321952 -355.0049247    593.1500369 338.4202468 43.15712191 220.1824202 2.478997041 20.7374755
1157794 2015    -2.3629225  8.97362183  2.723420881     74995       1.64E+18    6.32E+18    229.8566437 -7.722680025    158.6428948 -1221.28892 -97.23655906    354.0725008 40.02196936 229.5167593 10.25482897 20.80143585
1228327 2015    -3.42988705 5.308588578 -13.37482258        80459       1.64E+18    1.43E+18    246.3556824 54.3033862  154.083141  432.1309822 -171.480275 83.21001988 42.78373406 215.571553  73.27953741 21.41700889
1738793 2015    -1.270321809    2.001348019 -14.04640863        14101       1.64E+18    5.15E+18    45.46253226 -16.59445795    148.5102548 -362.4596545    -277.0012714    200.487095  -58.07567186    37.35829662 -32.25932639    22.22068775
1064572 2015    -2.037778399    -3.039336394    -15.0161247     113296      1.64E+18    2.83E+18    344.1405216 16.55224842 145.9815484 -1034.648206    -284.0509402    87.05641457 -38.18911995    352.1568528 21.44330765 22.60559664
1173697 2015    -17.90852019    13.0220451  24.83016718     33499       1.64E+18    5.56E+18    104.4377625 -44.29138222    126.6048874 -1102.657171    -43.16812553    254.3163266 -17.50991318    116.482897  -66.40829236    26.06534446
655696  2015    -22.38590201    -6.093846852    -23.03586292        101180      1.64E+18    2.25E+18    307.6379672 65.45073949 124.1262546 443.2987123 283.437887  99.93776535 15.05765261 13.29647764 74.88796701 26.585834
1256185 2015    24.66547834 -4.762621614    25.08080581     7751        1.64E+18    4.91E+18    24.95050248 -56.19640292    123.4952024 308.1350834 5.982346876 289.5927027 -59.66171073    347.1342692 -58.84097661    26.72168583
1912150 2015    -20.30290528    -11.55026801    -23.29050353        113576      1.64E+18    2.40E+18    345.0631066 -22.52410534    122.0376467 -902.1596218    57.98933432 37.13668142 -64.41048002    337.4378395 -14.87754029    27.04083608
366604  2015    -2.314899199    2.312022228 28.33517504     113229      1.64E+18    6.38E+18    343.9226074 -75.46308249    116.2181434 -1026.405758    -1059.609293    311.9953403 -39.56006409    298.252754  -59.36824507    28.39487797
1357395 2015    -1.735906861    -13.42657977    -2.083502575        109388      1.64E+18    2.63E+18    332.422836  -4.640828537    113.2458237 1132.403353 -22.32457637    55.89431153 -45.40304934    332.7238881 6.275623248 29.14014744
806444  2015    -5.388602305    10.50193917 -5.850151195        111802      1.64E+18    2.40E+18    339.6918941 -20.62146473    112.6819416 449.1358187 -79.48084862    37.81995354 -59.07567851    333.4743829 -11.18163968    29.28597034
1796912 2015    -0.477168414    1.798789979 7.798898411     40501       1.64E+18    3.09E+18    124.0316875 1.302825842 112.0359732 -376.2127689    60.45335668 221.7372989 19.37341685 126.0320226 -17.98110051    29.45482514
679768  2015    0.840712995 2.828494189 -8.901404702        66906       1.64E+18    1.47E+18    205.6797306 33.28712172 109.698871  -111.6817417    -712.4982322    65.12756908 77.33844414 188.607536  40.36375692 30.08235153
1906103 2015    2.675751558 11.67423908 2.949801736     23512       1.64E+18    2.98E+18    75.83268863 -17.3753865 107.9302432 -228.3015534    -444.7215448    217.5071037 -31.47548097    72.26082297 -39.94620791    30.57530403
2041755 2015    9.994889638 1.040685226 10.00061938     9786        1.64E+18    5.02E+18    31.44977897 -30.17620699    107.2636581 -525.4063451    103.8320412 227.9113354 -73.42376157    16.17268291 -39.83642274    30.76531286
122069  2015    -4.308413887    -5.415827401    24.1707376      23932       1.64E+18    2.98E+18    77.14822685 -18.17788468    106.8723318 503.0488078 -1400.482645    218.9138257 -30.60334385    73.7654253  -40.89559907    30.87796387
56921   2015    0.261788013 -1.168254025    -6.983095319        47780       1.64E+18    5.41E+18    146.121556  -45.77893574    105.8212882 -462.589425 -583.299323 272.243215  5.659008001 172.9487655 -54.30760833    31.18465156
861304  2015    -28.15131744    11.96184012 -30.92869094        47425       1.64E+18    5.43E+18    144.9402899 -41.06606924    103.9989634 -527.1676968    357.0398597 268.4601468 8.635415128 167.5686405 -50.80456017    31.7310855
995879  2015    -27.03135362    9.4066249   -28.36265833        21553       1.64E+18    2.73E+17    69.4226437  52.89163523 101.2334847 304.1338879 -475.1432381    153.238769  3.886231855 75.7580882  30.46495361 32.59790977
783864  2015    30.74831514 9.988029947 32.40711395     117828      1.64E+18    6.38E+18    358.4629003 -75.63411326    99.00951159 244.027732  -379.4147193    307.6179948 -40.96586523    302.3587916 -62.39288994    33.33013109
1226160 2015    -28.01579144    2.298666108 28.0794234      83043       1.64E+18    4.57E+18    254.5363399 25.74204234 96.37516351 -115.2974117    -508.0482222    46.52114208 35.33721638 248.9414918 48.05711361 34.24118704
1381057 2015    2.955172993 -3.231526755    -31.69723181        10279       1.64E+18    2.52E+18    33.08008972 3.567899928 94.79207881 -1762.465705    -1852.825298    158.4985385 -53.6239537 32.09780558 -9.183336911    34.81303545
1822114 2015    -4.677422561    17.07684424 5.985036868     108782      1.64E+18    2.68E+18    330.5409274 1.399069816 94.22101894 -452.4037867    -278.7316403    60.99307957 -40.29621712    333.1120889 12.58984064 35.02403219
  • This is a direct link to the folder where all the TGAS data is located. Going up from here will take you to other Gaia data archives. It's all hosted by the Gaia Archive at the ESA
  • The Math for converting arcs, etc to x,y,z:

    x = (distance in parsecs) times (Cosine of Right Ascension) times (Cosine of declination)

    y = (distance in parsecs) times (Sine of Right Ascension) times (Cosine of declination)

    z = (distance in parsecs) times (Sine of declination)

    distance (in parsecs) = 1 / (tangent [parallax {in arcseconds}])

    distance (in lightyears) = 1 / (tan [parallax {in milliarcseconds} /1000]).

If you want a full, accurate description of where the stars actually are, right now, you have to factor in the ref_epoch and run time forward to today based on the proper motion (pmra and pmdec), then factor for the time it takes for light to get to us from those stars, which is where the distance calculation really starts to shine.

As was stated in a comment, using parallax to measure distance isn't ideal when the parallax measurement has a high degree of uncertainty. Some of the entries in the TGAS database have calculated distances that are far beyond what should be have been possible to detect using that system.

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    $\begingroup$ cdn.gea.esac.esa.int/Gaia/gdr1/tgas_source/csv This is a direct link to the folder where all the TGAS data is located. Going up from here will take you to other Gaia data archives. It's all hosted by the Gaia Archive at the ESA $\endgroup$ Dec 8, 2021 at 18:25
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    $\begingroup$ The Math for converting arcs, etc to x,y,z: <p> x = (distance in parsecs) times (Cosine of Right Ascension) times (Cosine of declination) <p> y = (distance in parsecs) times (Sine of Right Ascension) times (Cosine of declination) <p> z = (distance in parsecs) times (Sine of declination) <p> distance (in parsecs) = 1 / parallax (in arcseconds) <p> distance (in lightyears) = 1 / (parallax (in milliarcseconds) /1000) $\endgroup$ Dec 8, 2021 at 18:32
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    $\begingroup$ @uhoh Not sure what that means "makes it a Stack Exchange answer", but...info has been added, as requested. $\endgroup$ Dec 9, 2021 at 20:49
  • $\begingroup$ That's great, thanks! I've moved your comments back into your post since comments should be considered temporary and can be deleted without warning. This definitely makes it a Stack Exchange answer! $\endgroup$
    – uhoh
    Dec 9, 2021 at 23:20
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    $\begingroup$ @uhoh Thank you! I wasn't sure how to do that myself (or just am not able to given my current status). I'd also like to thank whoever converted the "list" to a table. That was really helpful, and I didn't now how to do that, either. #ProfRob The Gaia database is hosted in the same place, if people are interested. The TGAS data was just easier to work with for my intended purpose. For those interested in exploring more (not sure if I mentioned), it is true that 1/parallax isn't the best way to measure distance, but a simple Google search will reveal a better way: "d = 1 au / tan(p)" $\endgroup$ Dec 11, 2021 at 21:48

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