Describe hubbles classification scheme for galaxies

Assignment Help Science

Reference no: EM131355943

1. a) The distance of planet Jupiter from the Sun is 5 AU. Express this distance in light year and parsec.

b) Calculate the ratio of the surface temperatures of the stars A and B from the following data:

Star	Absolute magnitude	Radius (RΘ)
A	2	62
B	6	4(5)

c) Show the horizon coordinates of a star X on a celestial sphere for a location at latitude 30° N.

d) Which telescope, optical or X-ray, would have higher resolving power for the same aperture? Calculate the magnitude of the faintest object that a 15 m optical telescope can detect.

e) The local time at Chennai is 9 p.m. Calculate the local time at Mumbai at that time.

2. a) Explain how we estimate the effective surface temperature of the Sun. A main sequence star has mass 2 × 1031 kg and radius 3 × 109 m. Obtain an estimate of the average temperature throughout the star.

b) Explain how sunspots survive for so long even though they are surrounded by hotter matter.

c) Derive an expression for the tidal force for the earth-moon system and show that its magnitude depends on the latitude. Explain tidal bulge on the basis of this expression.

3. a) Derive Jeans criteria for the stability of a gas cloud. A collapsing cloud is made only of neutral hydrogen (H1). If the temperature of the cloud is 50 K and its number density is 105 m^-3, calculate its Jeans mass.

b) Derive the expression for the mean temperature in a star:

<T> ∝ M^2/3 <Ρ>^1/3

c) The mean free path of photons in stars is of the order of 0.2 cm. Show that the time taken for a photon to reach the surface of a star of radius 4 RΘ is of the order of one million year.

d) Describe the composition of the interstellar medium. Explain how it has been possible to map the HI clouds.

4. a) Describe Hubble's Classification scheme for galaxies.

b) With the help of a diagram, explain the unified scheme for understanding active galactic nuclei.

c) What is cosmic background radiation? Explain why it is so important to the debate between evolving and a steady-state universe.

d) If the temperature of the background radiation today is 3 K, at what time after the birth of the universe was the temperature 10¹⁵ K. Take the age of the universe as 15 × 10⁹ years.

Reference no: EM131355943

Questions Cloud

Write a definition for representative volume element : Write a definition for Representative Volume Element. Draw a set of fibers in an hexagonal array: six fibers at the vertices of an hexagon plus one in the center, with the fibers touching each other.

Discretionary employee benefits : Analyze the various codes and acts regarding discretionary employee benefits discussed in Chapter 2 and determine which code or law has had the greatest impact on the largest number of organizations. Explain your rationale.

Compute the volume fraction vf : Compute the volume fraction Vf as a function of the fiber diameter df and the spacing between the centers of the fibers ax and ay in the two directions (center to center).

What manufacturing process would you recommend : What manufacturing process would you recommend to produce a large quantity of the following parts while minimizing cost?

Describe hubbles classification scheme for galaxies : Describe the composition of the interstellar medium. Explain how it has been possible to map the HI clouds - describe Hubble's Classification scheme for galaxies.

School curriculum that would help prepare students : What life skills would you add to the school curriculum that would help prepare students above and beyond what we've discussed here?

Analyze validity-constitutionality of officer jones actions : Officer Jones is a veteran officer with the Smithville police department. He received information that a citizen living in the local housing project was selling drugs. This information was conveyed to Officer Jones by an anonymous caller to the of..

Explain in your own words and in context of your situation : Explain in your own words and in the context of your situation, the answer to the question, "What is the probability of P(X = x | n, π )?

What manufacturing process would you recommend : What manufacturing process would you recommend to produce a large quantity of the following parts while minimizing cost?

User Account

All Pages