Calculating Absolute Magnitude of a Star - Red's Help

In summary, the absolute magnitude of a star is calculated by adjusting its apparent magnitude to what it would be if it were 10 parsecs away. This allows for a comparison of the true brightness of different stars, regardless of their distance from Earth. There are several methods for determining a star's distance in order to calculate its absolute magnitude, and it is possible for the absolute magnitude to change over time due to changes in its physical properties. Finally, the spectral type of a star is related to its absolute magnitude, with hotter stars having a higher absolute magnitude than cooler stars.
  • #1
redbaldyhead
9
0
Can anyone help me get my head around this one?
A star with a parallax angle of pi = 10 millisecs and has apparent magnitude of V= 10.2
How can I determine absolute magnitude:
I have the formula M=v -5logd -5 +A which can be ignored.
d=1/pi but I am always determining d which is less than that of the sun's distance!
Thanks Red
 
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  • #2
10 m'' = .010" , [tex]d=\frac{1}{p''}[/tex], where d is the distance in parsecs. Solve for d. This should probably be in the homework section.
 
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1. How is the absolute magnitude of a star calculated?

The absolute magnitude of a star is calculated by measuring its apparent magnitude (how bright it appears to us on Earth) and its distance from Earth. Using the inverse square law, the apparent magnitude is adjusted to what it would be if the star were 10 parsecs (32.6 light years) away, which is known as the absolute magnitude.

2. What is the significance of calculating the absolute magnitude of a star?

Calculating the absolute magnitude of a star allows us to compare the true brightness of different stars, regardless of their distance from Earth. This is important in understanding the intrinsic properties of stars and their evolution.

3. How can I determine the distance of a star in order to calculate its absolute magnitude?

There are several methods for determining the distance of a star, including parallax measurements, spectroscopic parallax, and the period-luminosity relation for certain types of variable stars. These methods rely on observational data and mathematical equations.

4. Can the absolute magnitude of a star change over time?

Yes, the absolute magnitude of a star can change over time due to changes in its physical properties such as temperature, size, and luminosity. This is especially true for variable stars, which exhibit variations in their brightness over time.

5. How does the absolute magnitude of a star relate to its spectral type?

The spectral type of a star is determined by its surface temperature, which in turn affects its luminosity. Therefore, there is a correlation between a star's spectral type and its absolute magnitude. For example, hotter stars of spectral type O have a higher absolute magnitude than cooler stars of spectral type M.

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