Questions tagged [stellar-classification]

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

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633 views

Why are type 1b and type 1c supernovae called type 1 rather than type 2; if they result from large exploding stars, rather than accreting dwarfs?

What similarities do types Ib and Ic supernovae have in common with type 1a? Are their spectra or their magnitudes more similar to accreting white dwarfs than the other supermassive, main sequence, ...
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2answers
83 views

Is there a way to convert a list of stellar fluxes to a star type?

If I look up a star on Simbad, (for instance this one), a list of fluxes in different bands might be given. Star classes (O, B, A, F, G, K or M) depend on the color of the star. The color of a star ...
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46 views

How far can a star's visual colour deviate from black body radiation?

The primary driver of a star's colour is its temperature, by way of black-body radiation. Black body radiation restricts stellar colour to a narrow slice of the full RGB spectrum. However, all stars ...
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2answers
90 views

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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31 views

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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1answer
64 views

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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40 views

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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42 views

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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1answer
340 views

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 ...
3
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1answer
80 views

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 ...
3
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1answer
139 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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2answers
67 views

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
292 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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1answer
77 views

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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1answer
421 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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1answer
71 views

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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1answer
121 views

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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1answer
84 views

"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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2answers
134 views

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$.