  # Astronomy Homework

Topics: Star, Sun / Pages: 4 (1028 words) / Published: Oct 2nd, 2014
1. The parallax of the star 75 Leo is 0.10 and its apparent visual magnitude is +5.18. The absolute visual magnitude of 75 Leo is +5.14. 2. A G2 I star is larger in diameter and more luminous than the sun. 3. spectroscopic parallax can be used to determine the distance to a star when the spectrum of the star can be used to determine its spectral type and luminosity class. 4. Luminosity class IV objects are known as sub giants. 5. For stars on the main sequence, the luminosity can be estimated by the formula L = M3.5. 6. The masses and diameters of each star in the binary can be determined from eclipsing binaries. 7. If we divide the mass of a star by its volume we calculate the star's average density. 8. Most stars on the H-R diagram are on the lower right. 9. The largest of the red stars are the super giant stars. Essay 10. Why would parallaxes be easier to observe if Earth were farther from the sun?
If Earth had a further orbit it would have a larger scale to measure distance to other planets/stars. Earth's current orbit cannot measure distances to far out stars because their distance is too great. But if Earths orbit was larger the stars much further out could be more accurately measured. 11. How does absolute visual magnitude tell us the intrinsic brightness of a star?
Absolute visual magnitude is a calculation with no relative varying distance, as opposed to something like visual magnitude which is comparing the stars brightness in relation to its distance from earth. Absolute magnitude is comparing all stars at a distance from 10 pc from that star. Essentially lining up all stars right next to each other. This more standard based measurement can help us determine to intrinsic brightness of the star, in another measurement based on all stars. 12. How do absolute visual magnitude