Questions tagged [stellar-classification]

Questions regarding the classification of stars based on temperature and luminosity.

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Any stellar entity named A1?

Is there a spatial entity (moon, planet, star, system, galaxy, cluster,..) that is identified with "A1" (or A{first_term})?
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Relationships between G magnitude, Johnson V magnitude, and spectral type of stars?

I'm simulating a population of binary stars for a summer research project. I'm adding uncertainties to my simulated observables such as angular position and radial (line of sight) velocity. I'm using ...
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Have all Wolf-Rayet stars evolved off the main-sequence?

From what I've read from various sources, Wolf-Rayet stars are massive, evolved stars that typically are the hottest, most luminous stars known. They experience high mass loss, taking their mass from $...
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Why is VX Sagittarii classified as spectral type M4-M10?

The largest and most luminous asymptotic-giant branch (AGB) star is VX Sagittarii. Wikipedia states that its spectral type is M4eIa-M10eIa (citing https://arxiv.org/pdf/astro-ph/0608438.pdf which in ...
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Stellar temperature ~ frequency relationship?

According to Wikipedia, 76% of all stars are of spectral type M, 12% are of K, 7.5% are of G, etc. (see this section on Stellar Classification). This is very helpful, but is too vague, as the ...
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Is there a formula to calculate any star mass from Luminosity, Radius, and/or Temperature (K)? [duplicate]

I know there is the Mass-Luminosity relationship, but I am wondering if there is a more accurate formula I can use based on the data points I have generated: Absolute Magnitude (based on class and ...
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How can I estimate how long will a main sequence star stay on the main sequence given its temperature?

I have a generic zero-age main sequence star. The only thing I know about it is its temperature. How can I estimate time time it spends on the main sequence (in millions of years)? I've seen equations ...
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75 views

Approximate spectral type and luminosity given apparent magnitude and distance

I am looking at the data acquired from the Gaia DR2 survey. I found that most of the stars had their distance and apparent magnitude catalogued, but not their spectral type and luminosity class. Is ...
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Eta Cassiopeiae star type; G0V? F9V? Both?

For a story I am looking into the star system of Eta Cassiopeiae, which is a binary with a main sequence star called Achird (very similar to the sun) and a K7V star. The issue I am running into is the ...
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1answer
173 views

Dataset for machine learning MK stellar classification

I would like to create program for automatic Morgan-Keenan stellar classification using machine learning. For that, I need dataset of stars with known absolute magnitude, temperature and luminosity ...
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Does “spectral type” and “stellar classification” refer to the same thing?

Should the tags stellar-classification and spectral-type be merged? has been asked in meta two weeks ago. It requires some careful consideration but so far no response has been forthcoming, so I'm ...
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334 views

How do we know that 2MASS J0523-1403 is a red dwarf?

I was reading about red dwarfs, and stumbled upon this article about the least massive red dwarf, and noticed several peculiarities: The spectral type is L2.5 The luminosity class is V The mass is 67....
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Is there a luminosity class for brown dwarfs?

I've been reading about brown dwarfs, and checking their spectral types, and I noticed that they do not have a luminosity class (V, VI, etc). So I am wondering, do brown dwarfs have a luminosity class,...
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Can red dwarf stars have a spectral type of L?

We have the "normal" main sequence stars, OBAFGKM. Below K and M are the brown dwarfs, L,T, and Y. Zooming into the area at the edges of M and L, we have spectral types M9, M9.5, L0, and L1. ...
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“Early” and “late” nomenclature regarding O, B & K, M stars

The Wikipedia article Stellar Classification has a subsection "Early" and "late" nomenclature. It says: Stars are often referred to as early or late types. "Early" is a ...
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Grammar of stellar classification

How to write G2V correctly (I mean space)? I saw in articles $ G\,2\,V$ and $G2\,V$, on the internet webside it is usually $ G2V$.