Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. In its orbit around the Galaxy supermassive blackhole (Sgr A), the star S0-2

ID: 1837390 • Letter: 1

Question

1. In its orbit around the Galaxy supermassive blackhole (Sgr A), the star S0-2 passes within 100 AU of the 4 106 Mo black hole. How many times the black hole's Schwarzschild radius does this distance represent? Is this close to the so-called "last stable orbit" around the black hole? Which method do astronomers use to measure the distance to Vega (a star about 25 light-year away from the Sun), the Andromeda Galaxy (a nearby galaxy, 800 kpc away) and a distant quasar in the early Universe (i.e, billion of light years away), respectively? 2.

Explanation / Answer

Q1:
S0-2 passes with in 100AU= 1.496x10^13 m
we know that,
Mass of earth, Me= 5.97x10^24Kg= 3x10^-6 Mass of black hole
There fore
Mass of black hole= 1.99x10^30 Kg

Schwarchild radius Rs= 2GM/c^2  
       Rs= 2X (6.67X10^-11)X (1.99X10^30)/ (3X10^8)^2
       Rs= 2.94Km it is aprroximately 3 Km.

Now, the distance of 100 AU= 4.98 x10^9 of Schwarchild radius.

Q2:
Parallax method for Vega,
Standard Candles for Andromeda galaxy,

Cosmotic distance ladder method for distant quassar.