Astronomers us the P-Cygni line features in a spectrum of a supernova to... Select one alternative: ...measure the velocity of the supernova ejecta. ...to measure the rotation speed of the star that exploded. ...measure the composition of the supernova ejecta more accurately than with other lines. ●...to measure the mass of the neutron star or black hole formed in the supernova.

When observed from Earth, the wavelengths of light emitted by a star are shifted toward the red end of the electromagnetic spectrum. Why does this redshift occur? A The star is at rest relative to Earth. The star is moving toward Earth at decreasing speed. The star is moving toward Earth at increasing speed. D The star is moving away from Earth. DOOO

Please only type answer

Do it asap

!

A 1.4 M. neutron star and a 0.5 M. white dwarf have been found orbiting each other with a period of 16 minutes. What is their average separation? Convert your answer to units of the Sun's radius, which is 0.0047 AU. (Hints: Use the version of Kepler's third law for binary stars, MA + MB make sure you express quantities in units of AU, solar masses, and years. Note: a year is 3.2 x 1o' s.) %3D solar radii

Consideration of the total energy in a radio lobe of an AGN implies that the energy is distributed evenly between the particles in the lobes and the magnetic field. This implies that the magnetic field scales with observed luminosity L as Select one: a. [417 O b. is independent of L ○ c. 11/11 O d. 12/7 ○ e. L

For each statement concerning main sequence stars, select T True, F False, G Greater than, L Less than, or E Equal to. A) The surface temperature of a O type star is .... than a K type star. B) On the main sequence, the mass of a O type star is .... than a F type star. C) On the main sequence, a M type star's life is .... than a G type star. D) The surface temperature of our Sun is .... than the surface temperature of Sirius. E) When stars start hydrogen burning, thier mass determines where they are on the main sequence. F) Based on the relative lifes of M and G type stars we expect the number of M stars to be .... than the number of G type stars.

7. Let's characterize a typical neutron star. (a) Compute its luminosity in units of the solar luminosity. Consider that the neutron star has a surface effective temperature of 106 K and a radius of 7 km. (b) In which wavelength does the neutron star radiate most energy (in nm)? (c) In which region of the spectrum it will be easier to detect / observe such an object (look at Figure 2)? mmmmmm 0.0001 nm 0.01 nm Gamma rays 400 nm Increasing energy X-rays Increasing wavelength 10 nm 1000 nm 0.01 cm Ultra- violet Infrared Visible light 500 nm 600 nm Figure 2: Electromagnetic spectrum 1 cm 1m Radio waves Radar TV FM 700 nm 100 m AM

Indicate whether the following statements are true or false.   (Select T-True, F-False. If the first is T and the rest F, enter TFFFFF). A) White dwarfs are small dense objects about the size of the Earth.   B) White dwarfs are composed mostly of hydrogen.   C) A planetary nebula forms when a star violently explodes.   D) A planetary nebula is the remnant of the outer envelope of a star.   E) A white dwarf is the remnant of the star's core visible after the outer layers have been ejected.