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08-18-2018, 08:15 PM | #1 |
Join Date: Aug 2010
Location: The Land of Enchantment
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Stellar Mapping
Not sure where to put this, but ultimately it is for GURPS, so...
Where can I find a complete dataset for all stellar objects within 10 parsecs of Sol? I need RA, DEC and parallax. I'm trying to make an up-to-date Astrosynthesis file, and I know that this 10pc list is sort of the whole purpose of RECONS, which had an update this year. Yes, I know that there are real-life stellar maps already available for Astroynthesis (from Evil Doctor Ganymede, generally) but they all date to 2012 and a LOT of objects have been added since then, mostly various dwarfs. I found this RECONS set, but it is limited to certain spectra (looks like L, M, and WD, and a few K) and excludes stars on the RECONS list of 100 nearest stars. I'd like EVERYTHING within 10pc. Basically, I want a list of everything on the RECONS census. The 100 Nearest list goes out to about 22.7ly, and 10pc is 32.6ly, so there have to be more A, F, G, and K stars out there... I can't find RECONS on the Vizier website. Is there something else that it might be named? Actually, if I could get a list as accurate as RECONS for everything within 43ly that would be even better. Then I could make eight sectors that are 25ly cubes. But I doubt that such a data set exists.
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I'd need to get a grant and go shoot a thousand goats to figure it out. Last edited by acrosome; 08-20-2018 at 08:55 AM. |
08-18-2018, 09:02 PM | #2 |
Join Date: Dec 2007
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Re: Stellar Mapping
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08-18-2018, 09:09 PM | #3 | |
Join Date: Aug 2010
Location: The Land of Enchantment
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Re: Stellar Mapping
Quote:
It only lists 208 stars for a 32ly search, so it obviously does not include the up-to-date RECONS data, which should list 428 stars. Even removing companion stars to only lists stellar systems it should be 317.
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I'd need to get a grant and go shoot a thousand goats to figure it out. Last edited by acrosome; 08-20-2018 at 08:22 AM. |
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08-20-2018, 08:55 AM | #4 |
Join Date: Aug 2010
Location: The Land of Enchantment
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Re: Stellar Mapping
I know that there is a Big Brain on this forum somewhere who knows the answer... :)
RECONS publishes their data- or at least the three data that I need (RA DEC parallax). I just can't find it. Should I just use Hipparcos (or Gliese? which is better?) and add in all those dwarfs from CTIOPI? EDIT-- Dammit. Hipparcos doesn't list the stellar class... It lists BVI color index, magnitude, and luminosity, but I cannot easily translate that into class. Also, Vizier is truncating all of my searches to 50 stars, and I can't figure out how to get a full list. I didn't list it above, but I sort of assumed any catalogue would have stellar class, luminosity, and magnitude, all of which I want as well.
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I'd need to get a grant and go shoot a thousand goats to figure it out. Last edited by acrosome; 08-20-2018 at 09:46 AM. |
08-20-2018, 11:21 AM | #5 |
Join Date: Aug 2010
Location: The Land of Enchantment
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Re: Stellar Mapping
I found some other archives where you can search stellar datasets (other than Vizier). Here is one from the Gaia project. And here is one from NASA.
So I'll get this eventually, but for now I'm still struggling. For instance, searches are often truncated to 1000 or 2000. But I'm only expecting several hundred star systems, so that should work, yet I keep hitting the max on my searches. The Hipparcos search doesn't let you limit the search by parallax, just RA and DEC, so that's a bother since otherwise it has everything I want. Some datasets do let you limit a search by parallax, but I am clearly not understanding how that works or something because when I try to limit my search to 10 parsecs in the Gaia dataset I get 1722 objects, of which 63 appear to be closer than Proxima Centauri. (And, yes, I am converting milliarcsec to arcsec.) And I keep seeing parallaxes that are listed as a negative number! How in the hell do you get a negative parallax?!? Grrr. As I said, I'm not understanding something.
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I'd need to get a grant and go shoot a thousand goats to figure it out. |
08-22-2018, 01:58 PM | #6 | |
Join Date: Jul 2008
Location: Munich, Germany
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Re: Stellar Mapping
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So if you want only stars between 5 and 6 parsecs, you could enter "5..6" in the "Dist" row (20th row, I think). To get all stars with distances <= 10 pc, you'd enter "<= 10" in the box. At the top of the list of columns, there's a link "Constraints (?)" which will give you a pop-up window explaining the formatting of how to specify constraints. |
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08-20-2018, 11:21 AM | #7 |
Join Date: Aug 2004
Location: traveller
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Re: Stellar Mapping
Have you written to RECONS to ask them? Todd Henry ( toddhenry28@gmail.com ) was the lead author on the most recent paper.
A negative parallax could be the result of high proper motion or noisy data with large error bars. |
08-22-2018, 05:24 AM | #8 |
Join Date: May 2005
Location: Oz
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Re: Stellar Mapping
You can get wacky parallaxes from telescopic binaries, too.
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Decay is inherent in all composite things. Nod head. Get treat. |
08-21-2018, 01:13 AM | #9 | |||
Join Date: May 2005
Location: Oz
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Re: Stellar Mapping
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Decay is inherent in all composite things. Nod head. Get treat. |
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08-21-2018, 02:27 PM | #10 |
Join Date: Aug 2008
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Re: Stellar Mapping
Have you tried this catalog search? It does list the spectral type for stars in hipparcos:
https://heasarc.gsfc.nasa.gov/db-per...n=More+Options
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