A supernova in a distant galaxy is observed to be having an absolute magnitude of -19 and an apparent magnitude of 17. Estimate the distance to the galaxy.

(a) The figure shows the three stars and their velocities. Which star has the largest proper motion? Which star has the smallest proper motion? A B Earth

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Problem Set on Binary Systems: 1.Consider two stars in orbit about a mutual center of mass. If a1 is the semimajor axis of the orbit of star of mass m, and a, is the semimajor axis of the orbit of star of mass m2, prove that the semimajor axis of the orbit of the reduced mass is given by a = a, + a2. points)

(Astronomy) PSR1913+16 Problem II. Using only the Figure, what are the maximum radial velocities as found from the redshift and blueshift, respectively? Note: redshifts have positive radial velocities values in the figure, whereas blueshifts have negative radial velocity values.  (Answer in km/s)

The star HD 69830's mass is 1.7 ✕ 1030 kg, its radius is 6.3 ✕ 105 km, and it has a rotational period of approximately 35 days. If HD 69830 should collapse into a white dwarf of radius 7.8 ✕ 103 km, what would its period (in s) be if no mass were ejected and a sphere of uniform density can model HD 69830 both before and after?

A star with a trigonometric parallax of .02 arcseconds has a distance of O2.0 light years. 50 pc. 4 kpc. 20 pc. O need more information (magnitudes)

31) Star Sirius has an apparent magnitude of -1.47 and an absolute magnitude of 1.41. Estimate the distance to Sirius.

Time left 1:45:56 A star has initially a radius of 680000000 m and a period of rotation about its axis of 33 days. Eventually it changes into a neutron star with a radius of only 45000 m and a period of 0.3 s. Assuming that the mass has not changed, find Assume a star has the shape of a sphere. (Suggestion: do it with formula first, then put the numbers in) [Recommended time : 5-8 minutes] (a) the ratio of initial to final angular momentum (Li/Lf) Oa. 2.17E+15 Ob. 24 Oc. 0.0416 Od. 4.61E-16 (b) the ratio of initial to final kinetic energy Oa. 4.85E-23 Ob. 396000 Oc. 2.53E-6 Od. 2.06E+22

38.  Many RR Lyrae stars are found in open clusters in the plane of the galaxy.     True     False