# Questions tagged [spectral-type]

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### Has J been used by itself as a spectral type?

While answering the question "Why have brown dwarf classes been dubbed L, T and Y?" I noticed that in the paper Kirkpatrick et al. (1999) "Dwarfs Cooler than 'M': The Definition of Spectral Type 'L' ...
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### Do we know a star that is similar to the Sun when it would be a red giant?

In about 5 billion years the Sun is predicted to become a red giant and have more than 200 times its current size, reaching a radius of about 5 AU when largest. I wonder what spectral class the Sun ...
27 views

### How are Y-dwarf spectral subtypes defined?

It is often stated that the spectral subtype indicates the relative position between spectral types, e.g. G5 being halfway from the start of spectral type G to the beginning of spectral type F. Given ...
51 views

### Spectral Class Breakdown

Where can I get a more detailed breakdown of Spectral Classes. Wikipedia only has it at Letter level rather than sublevel. For example, https://en.wikipedia.org/wiki/Stellar_classification has B ...
48 views

### Examples of absorption lines for main sequence stars

Where might I find a detailed table or figure containing the absorption lines and their corresponding wavelengths for each type of main sequence star? I'm trying to get the chemical abundance of ...
62 views

### Compare this planet to Earth and determined its habitability (can humans live in this environment?) [closed]

I'm given this set of data and I need to describe the habitability. Would this not be habitable since the temperature of the albedo and the equilibrium is similar to Earth's or does the Spectral Type ...
45 views

### Can Jupiter's nightside be classified as spectral type Y?

As far as I am aware, the latest spectral types that have been assigned are around Y2, for objects like WISE 0855-0714 that have temperatures around 250 K or so. I've also seen several directly-imaged ...
79 views

### How a star's rotation affects a star in the main sequence?

I searched and have found that the questions mainly focus on neutron stars, white dwarves and black holes. This was not what I looked for. Basically, the bigger the star's mass is, the more intense ...
91 views

### Need help understanding stellar spectroscopy data from ESO

The European Southern Observatory webpage has a web page that has tabular spectrogram data from A. J. Pickles, University of Hawaii. There are over 130 .dat files there. Each one represents a ...
69 views

### Stellar electromagnetic signatures

By using only the electromagnetic signature of a star, could a star be distinguished with reliable accuracy from any other star? To elaborate a little, say we have a collection of about 200,000 stars. ...
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### Can someone explain this diagram showing the spectral type distribution of bright stars

Can someone explain this diagram? The text is in Dutch, free translation: "You are given a graph: a histogram of the 10 000 most apparent bright stars. Explain 1, 2 and 3." The fact that the number ...
812 views

### B-V to U-B colour index

Is there a formula to convert the B-V index to U-B index or are they totally different and separate observations and can't be convert like you can with Fahrenheit->Celsius? (Updated) I know F->C ...