100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Introduction to Astrophysics Exam Paper £4.49   Add to cart

Exam (elaborations)

Introduction to Astrophysics Exam Paper

 4 views  0 purchase

Introduction to Astrophysics Exam Paper

Preview 2 out of 10  pages

  • December 10, 2023
  • 10
  • 2019/2020
  • Exam (elaborations)
  • Only questions
avatar-seller
astroboy
PHY104




PHY472

Data Provided:
Formula sheet and physical constants
Data Provided:
A formula sheet and table of physical constants is attached to this paper.


DEPARTMENT OF PHYSICS & Autumn Semester 2009-2010
ASTRONOMY

DEPARTMENT OF PHYSICS AND ASTRONOMY
ADVANCED QUANTUM MECHANICS 2 hours
Spring 2020


AnswerIntroduction to Astrophysics
question ONE (Compulsory) and TWO other questions, one each from3 hours
section A and section B.
Instructions:
All questions are
Answer all marked
FOUR out offrom
questions ten.Section
The breakdown
A and ONE on the right-hand
question side
from Section B. of the
paper is meant as a guide to the marks that can be obtained from each part.
Answering the exam questions should take no more than NINETY minutes, but you will have
THREE hours in a 24-hour window to complete the exam and upload your answers to Black-
board.

Section A is worth 20 marks in total and all questions in section B are worth 15 marks each.
The breakdown on the right-hand side of the paper is meant as a guide to the marks that can
be obtained from each part.

Cross through any work that you do not wish to be examined.




PHY104 TURN OVER

1



PHY472 TURN OVER

, PHY104


SECTION A

1. A star has an absolute visual magnitude of 4.0. What is the apparent visual magnitude
of an unresolved star cluster, if it consists of 500 of these stars, is located at a distance
of 2.0 kpc, and has a colour excess of E(B-V) = 0.30 mag? [5]

Note: You may assume that the ratio of visual extinction to colour excess is 3.0



2. For a galaxy cluster in spherical equilibrium, the virial theorem can be used to derive
a statistical estimate of the total mass of the cluster:
5Rc hvr2 i
Mc = ,
G
where Mc is the mass of the cluster, Rc is the radius of the cluster, and hvr i is the
mean radial velocity of galaxies within the cluster. Estimate the total mass of a rich
cluster, which sits at an average distance of 19 Mpc, has an angular diameter of 2.6◦ ,
and whose galaxies have a mean radial velocity relative to each other of 375 km s−1 . If
the cluster is host to 200 major galaxies, with 90% of the cluster mass attributed to
intra-cluster medium, what is the average mass of each galaxy in Solar masses? [5]



3. A binary system has an apparent V-band magnitude of 6.7 mag. If the system has
a parallax of 2.4 milli-arcsec, and the primary is 0.8 magnitudes brighter than the
secondary in the V-band, what are the absolute V-band magnitudes of the two compo-
nents? Estimate the spectral types of the components if B−V = –0.15 for both stars.
[5]



4. Runaway stars are usually defined as having peculiar space velocities in excess of
30 km s−1 . A bright star in the Small Magellanic Cloud (distance 60 kpc) has an
anomalous proper motion of 0.10 ± 0.05 milli-arcsec per year as measured by the
GAIA satellite. In addition, it has an observed radial velocity of 150 ± 5 km s−1 ,
versus an average of 135 km s−1 for neighbouring stars. Is the star a runaway? Show
your working to justify your answer. How would its radial velocity be measured in
practice? [5]




PHY104 CONTINUED

2

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller astroboy. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £4.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

73216 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now

Start selling
£4.49
  • (0)
  Add to cart