The absolute magnitude of a star in the Andromeda galaxy (distance 690 kpc) is M = 5. It explodes as a supernova, becoming onebillion (10 9 ) times brighter. What is its apparent magnitude?

Calculate the absolute magnitude of a star at a distance of 6 pc with an apparent magnitude of 3.

An object was discovered on Feb. 24.37 UT (position R.A. = 5h35m.8, Decl. = -69 18'), obtained m = 4.8 on Feb. 24.454 UT. This object proved to be the most famous supernova (SN) in the 20th Century and the brightest visible from Earth since 1604. It is classified as a SN of the type Il in the Large Magellanic Cloud (SN1987A). Its brightness peaked in May 1987, with an apparent magnitude of m = 2.8. a) Find the absolute magnitude M of the SN1987A at maximum. Distance of the LMC is 51,400 pc. b) The progenitor (before SN explosion) star was a blue supergiant of the apparent magnitude m = 12.8. How much brighter (in terms of flux density) this SN was at maximum compared to the progenitor star. Find the ratio FSN/ Ebetore

Calculate the size of a star if its surface temperature is 6000 K and has a power output of 5.6 x 1026 W.

What is the lifetime on the main sequence of a star whose surface temperature is 6500° K and whose radius is 2 X 109 m ? ( LS=3.826 X 1026 J/s)

"H-R" Diagram pg. 118, question 7 Stars of the same spectral type have the same: absolute magnitude number temperature luminosity

International Astronomical Union reported on 24 Feb 1987: An object was discovered on Feb. 24.37 UT (position R.A. = 5h35m.8, Decl. = -69 18'), obtained m = 4.8 on Feb. 24.454 UT. This object proved to be the most famous supernova (SN) in the 20th Century and the brightest visible from Earth since 1604. It is classified as a SN of the type Il in the Large Magellanic Cloud (SN1987A). Its brightness peaked in May 1987, with an apparent magnitude of m = 2.8. a) Find the absolute magnitude M of the SN1987A at maximum. Distance of the LMC is 51,400 pc. b) The progenitor (before SN explosion) star was a blue supergiant of the apparent magnitude m = 12.8. How much brighter (in terms of flux density) this SN was at maximum compared to the progenitor star. Find the ratio FSN / Ebefore

You measure a star to have a parallax angle of 0.12 arc-seconds What is the distance to this star in parsecs? 8.33 Hint: d = 1/p What is the parallax angle of a different star that is twice as far away as the star from the previous problems? [answer in arc-seconds without including the unit]

A star has a distance of 40 pc. What is the parallax of the star?

15: A star has a parallax angle of 0.0270 arcseconds and an apparent magnitude of 4.641. What is the distance to this star?  Answer: 37 16: What is the absolute magnitude of this star? Answer:1.8 17: Is this star more or less luminous than the Sun? Answer "M" for More luminous or "L" for Less luminous. (HINT: the absolute magnitude of the Sun is 4.8) Answer: M  18: What is the luminosity of this star? (HINT: The luminosity of the Sun is 3.85×1026 W.) Please answer question #18, #15-17 are correct, the photos provide the work for them.