Astronomy | Astrophysics Answers

Show the horizon coordinates of a star X on a celestial sphere for a location at latitude 60°N . would these coordinates be same at the latitude 30° N.

obtain an expression for the radial velocity of objects in the galaxy as a function of their galactic longitude . for 5marks

The mean free path of photon stars is is of the order of 0.2 centimetre. Show that the time taken for a Photon to reach the surface of a star of radius 4R is of the order of 1 million year.

Can someone please explain to me what physically carries and thus produces the current in the Heliospheric Current Sheet. My understanding is that the charge carrier is the ions of the plasma within the interplanetary medium. Are these not the same ions that make up the out-flowing Solar Wind? What physically creates the two currents in the sheet? Is the current simply a relative difference between the number of outflowing positive versus negative charged particles, as a result of the magnetic field polarity? Thank you in advance.

An electron is moving with a speed of 0.97c in a magnetic field of strength 10 to the power 8
G.
Calculate the peak frequency at which the electron will radiate.

I need help with an early step in the derivation of the parker solar wind formula. My question is regarding the sign of dP/dr right here: density • dv/dt = -dP/dr - GM(sun)•density/r^2. Why is the sign of dP/dr negative. This is the first step in developing the radially symmetric outflow. Regarding the forces involved, the left side of the equation represents the force driving the wind and the right side is the overall outward force due to pressure minus the force of gravity. IE. residual outward force, equals total outward force minus inward force. Why isn’t dP/dr positive? Thank you.

A white drawf star has a mass 10^30 kg. It's luminosity is 10^24j/s. Calculate how long it can survive with its present luminosity if it's internal temperature is 10^7k .

Would the relationship between weight and mass on Our Planet relationship change on Mercury? Explain your answer. *

A main sequence star has mass 2×1031 kg and radius 3×109
m. Obtain an estimate of the
average temperature throughout the star. Examine if Newton’s theory would be adequate
for the study of this star.

Calculate the ratio of temp of stars1 wih absolute magnitude_3and radius_72and star 2 with magnitude 8and radius 6