How to estimate star's mass without gravitation constant?

In summary, the question being discussed is about determining the spectral class and mass of a main sequence star based on its color and absolute luminosity. The conversation also touches on the use of G (gravitational constant) in estimating the mass of a star. The person asking the question, smm, is asked to clarify their question for better understanding.
  • #1
smm
31
0
hi! title tells all
 
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  • #2
smm said:
hi! title tells all

Hey!

If it is a main sequence star, you can tell what spectral class it belongs to by looking at its color. Every class has certain features, among them mass.
 
  • #3
Using absolute luminosity, and the surface temperature(represented by spectral class), you could calculate the total Mass.
 
  • #4
Welcome to Physics Forums smm! (and a belated welcome to orange as well).

I'm not sure I understand smm's question ... no matter how you arrive at an estimate of the mass of a star, somewhere in the chain of observation and logic, you will use G.

For example, if you estimate its mass from its absolute luminosity, you are relying indirectly on G, because theories which lead to an understanding of the mass-luminosity relationship have gravity (and hence G) as a key element. Similarly, if you use a mass-luminosity relationship as a purely observational device (i.e. you've observed enough stars to plot the relationship, even if you have no idea of why it should be like that), you'll find that observations which established the mass of stars in your empirical relationship depended on G.

Perhaps you could clarify your question a bit for us please smm?
 

1. How do scientists estimate the mass of a star without using the gravitational constant?

Scientists use a variety of methods to estimate the mass of a star without relying on the gravitational constant. These methods include studying the star's luminosity, temperature, and spectral type, as well as observing its orbit and interactions with other celestial bodies.

2. Why is it important to be able to estimate a star's mass without using the gravitational constant?

While the gravitational constant is a fundamental constant in physics, it can be challenging to accurately measure and can introduce uncertainties in calculations. By using alternative methods to estimate a star's mass, scientists can obtain more precise and reliable results.

3. What is the relationship between a star's mass and its luminosity?

There is a direct relationship between a star's mass and its luminosity. Generally, the more massive a star is, the brighter it will be. However, other factors such as temperature and chemical composition can also affect a star's luminosity.

4. How does a star's spectral type help in estimating its mass?

A star's spectral type, determined by its surface temperature and chemical composition, can provide valuable information about its mass. By comparing a star's spectral type to known standards, scientists can estimate its mass based on its position on the Hertzsprung-Russell diagram.

5. Can a star's mass be accurately estimated without directly observing it?

Yes, scientists can estimate a star's mass without directly observing it. This is possible through various indirect methods, such as analyzing the gravitational effects of the star on its surrounding objects or studying its pulsation patterns. However, direct observations, such as through interferometry or gravitational lensing, can also provide precise measurements of a star's mass.

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