<p>If you are just interested in supergiants (note that the massive progenitors of supernovae are more likely to be main sequence stars, since that is where stars spend most of their [short] lives) then the problem amounts to selecting stars in a certain portion of the observational Hertzsprung-Russell diagram (absoloute magnitude versus colour). In the case of Gaia DR3 (or EDR3) this woud be absolute G magnitude versus Bp-Rp.</p>
<p>I do not know what restrictions you want to place on the types of progenitor you wish to find but let's say that you wanted stars cooler than some colour and with an absolute magnitude less than -5  (the absolute magnitude of Betelgeuse is about -6).</p>
<p>The distance modulus at 300 pc is <span class="math-container">$5\log d -5 = 7.38$</span>, so your candidate stars would have to be brighter than about G=2.38 (if the star was closer than 300 pc, or more luminous, then of course it would be brighter). NB: I have however ignored extinction, but this should be a small effect within 300 pc.</p>
<p>So you go to the Gaia catalogue and request all stars <em>brighter than</em> G=2.38 and with a parallax greater than 3.333 milli-arcsec. From these few stars you can choose the ones in the colour/temperature range that you want.</p>
<p>Unfortunately you will probably find that data for extremely bright stars (G&lt;3) is missing from the Gaia catalogue. The stars are too bright to be recorded and measured properly.</p>
<p>You probably would do better by search the <a href="http://tdc-www.harvard.edu/catalogs/bsc5.html" rel="nofollow noreferrer">Yale Bright Star Catalogue</a> for objects with V&lt;2.38 and a colour redder than some threshold (the catalogue also has spectral types, so you could just strip out the class I luminosity sources using this). You will then have to individually search for distance information to those stars (their parallaxes will not be very good).</p>
<p>You might find <a href="https://iopscience.iop.org/article/10.3847/1538-3881/ab1cbd" rel="nofollow noreferrer">Messineo &amp; Brown (2019)</a> of interest. They produce a catalogue of red supergiants using the Gaia DR2 data (which still has the bright star problem).</p>

CC BY-SA 4.0
2022-06-27T14:14:05.920Z
Thanks. But i have some questions. 5logd−5=7.38 this calculation is for at 300 pc. But i want 300 or closer ones so what am i suppose to do? When I take 1 parsec 5 * log1 - 5 = -5. So what doest it mean? Do I need to take G mag between 7.28 and -5? Also in gaia catalog there is no absolute magnitude but apparent magnitude. I guess you offer to use that variable? At last, why G=2.38 rather than G=7.38?
Aegean
CC BY-SA 4.0
2022-06-27T14:17:54.997Z
Any star that is closer, or is more luminous, will of course be brighter than G=2.38. The Gaia catalogue does not contain absolute magnitude because you need to calculate it yourself using whatever assumptions you need to make about what the distance is (not necessarily just the reciprocal of parallax) and what the extinction is (I assumed it was negligible in my answer). @Aegean
ProfRob
CC BY-SA 4.0
2022-06-27T14:26:49.307Z
thanks again totally understood well
Aegean
CC BY-SA 4.0
2022-06-27T14:40:27.260Z
But still with g=2.38 or smaller betelgeuse isn't in the list. Why is it?
Aegean
CC BY-SA 4.0
2022-06-27T14:41:36.830Z
I said why in my answer. @Aegean
ProfRob
CC BY-SA 4.0
2022-06-27T14:45:16.277Z
Ah okay, I missed that part, now I see.
Aegean
CC BY-SA 4.0
2022-06-27T18:32:57.150Z
@ProfRob Are there any type 1a supernova candidates that are very close to the Chandrasekhar Limit of 1.4 solar masses?  I could post a separate question ...
Sheldon
CC BY-SA 4.0
2022-06-27T09:32:57.437Z
2022-06-27T14:19:37.697Z
2022-06-27T14:19:37.697Z
ProfRob
<p>I want to find supernova candidates by using the Gaia catalog in 300 parsec (near Earth). I though they must be red super giants so they are cooler than 4100 K and more luminous than 10<sup>4</sup> solar luminosity. However, there is no data for luminosity for those stars. So I need another parameter related with brightness, magnitude or luminosity etc. Any suggestions?</p>

CC BY-SA 4.0
2022-06-26T18:21:28.590Z
Well there are luminosities available in the Gaia DR3 catalogue, and if not, you can easily calculate them from the absolute G magnitude and an estimated bolometric correction.
ProfRob
CC BY-SA 4.0
2022-06-26T18:27:47.040Z
However, if you are only interested in the progenitors in the supergiant phase then there are few (one?) within 300pc, and they are so bright and large that their distances will be quite uncertain.
ProfRob
CC BY-SA 4.0
2022-06-26T18:57:41.363Z
the problem is I cannot find absolute g magnitude in DR3 with parallaxes. and yes there must be a few stars like 6 or 10
Aegean
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2022-06-26T19:34:35.603Z
There are G magnitudes and parallaxes...
ProfRob
CC BY-SA 4.0
2022-06-26T20:18:21.913Z
There are but not together. They are in different catalogs.
Aegean
CC BY-SA 4.0
2022-06-26T20:19:59.280Z
When i go the site https://gea.esac.esa.int/archive/ and search with gaiadr3.gaia_source there is no absolute G magnitude, there are only some "mean G mangitudes" or "BP-PR magnitudes"
Aegean
CC BY-SA 4.0
2022-06-26T21:27:01.837Z
Calculate the absolute magnitude!
ProfRob
CC BY-SA 4.0
2022-06-27T07:50:46.610Z
Calculate for millions of objects??!
Aegean
<supernova><gaia><red-supergiant>
What criteria determines whether stars are supernova type II candidates?
Aegean
# What criteria determines whether stars are supernova type II candidates?

(Asked by: username_0 on 2022-06-26)

I want to find supernova candidates by using the Gaia catalog in 300 parsec (near Earth). I though they must be red super giants so they are cooler than 4100 K and more luminous than 104 solar luminosity. However, there is no data for luminosity for those stars. So I need another parameter related with brightness, magnitude or luminosity etc. Any suggestions?

**Tags:** supernova, gaia, red-supergiant
> **Comments:**
> **username_1**: Well there are luminosities available in the Gaia DR3 catalogue, and if not, you can easily calculate them from the absolute G magnitude and an estimated bolometric correction.  
> **username_1**: However, if you are only interested in the progenitors in the supergiant phase then there are few (one?) within 300pc, and they are so bright and large that their distances will be quite uncertain.  
> **username_0**: the problem is I cannot find absolute g magnitude in DR3 with parallaxes. and yes there must be a few stars like 6 or 10  
> **username_1**: There are G magnitudes and parallaxes...  
> **username_0**: There are but not together. They are in different catalogs.  
> **username_0**: When i go the site https://gea.esac.esa.int/archive/ and search with gaiadr3.gaia_source there is no absolute G magnitude, there are only some "mean G mangitudes" or "BP-PR magnitudes"  
> **username_1**: Calculate the absolute magnitude!  
> **username_0**: Calculate for millions of objects??!  

---

## 1 answers

### Answer by username_1 on 2022-06-27. Score: 3 | Accepted answer

If you are just interested in supergiants (note that the massive progenitors of supernovae are more likely to be main sequence stars, since that is where stars spend most of their [short] lives) then the problem amounts to selecting stars in a certain portion of the observational Hertzsprung-Russell diagram (absoloute magnitude versus colour). In the case of Gaia DR3 (or EDR3) this woud be absolute G magnitude versus Bp-Rp.

I do not know what restrictions you want to place on the types of progenitor you wish to find but let's say that you wanted stars cooler than some colour and with an absolute magnitude less than -5 (the absolute magnitude of Betelgeuse is about -6).

The distance modulus at 300 pc is $5\log d -5 = 7.38$, so your candidate stars would have to be brighter than about G=2.38 (if the star was closer than 300 pc, or more luminous, then of course it would be brighter). NB: I have however ignored extinction, but this should be a small effect within 300 pc.

So you go to the Gaia catalogue and request all stars *brighter than* G=2.38 and with a parallax greater than 3.333 milli-arcsec. From these few stars you can choose the ones in the colour/temperature range that you want.

Unfortunately you will probably find that data for extremely bright stars (G<3) is missing from the Gaia catalogue. The stars are too bright to be recorded and measured properly.

You probably would do better by search the [Yale Bright Star Catalogue](http://tdc-www.harvard.edu/catalogs/bsc5.html) for objects with V<2.38 and a colour redder than some threshold (the catalogue also has spectral types, so you could just strip out the class I luminosity sources using this). You will then have to individually search for distance information to those stars (their parallaxes will not be very good).

You might find [Messineo & Brown (2019)](https://iopscience.iop.org/article/10.3847/1538-3881/ab1cbd) of interest. They produce a catalogue of red supergiants using the Gaia DR2 data (which still has the bright star problem).

> **Comments:**
> **username_0**: Thanks. But i have some questions. 5logd−5=7.38 this calculation is for at 300 pc. But i want 300 or closer ones so what am i suppose to do? When I take 1 parsec 5 * log1 - 5 = -5. So what doest it mean? Do I need to take G mag between 7.28 and -5? Also in gaia catalog there is no absolute magnitude but apparent magnitude. I guess you offer to use that variable? At last, why G=2.38 rather than G=7.38?  
> **username_1**: Any star that is closer, or is more luminous, will of course be brighter than G=2.38. The Gaia catalogue does not contain absolute magnitude because you need to calculate it yourself using whatever assumptions you need to make about what the distance is (not necessarily just the reciprocal of parallax) and what the extinction is (I assumed it was negligible in my answer). @Aegean  
> **username_0**: thanks again totally understood well  
> **username_0**: But still with g=2.38 or smaller betelgeuse isn't in the list. Why is it?  
> **username_1**: I said why in my answer. @Aegean  
> **username_0**: Ah okay, I missed that part, now I see.  
> **username_2**: @ProfRob Are there any type 1a supernova candidates that are very close to the Chandrasekhar Limit of 1.4 solar masses?  I could post a separate question ...  

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