ASM510-Dreamworks Training Consulting Company Case Study - IT Computer Science Assignment Help
- Subject Code :
ASM510
- Country :
Malaysia
1.
Choose the most reasonable of the given alternatives for the following (do not give a motivation):
|
(a) Surface pressure at Mars (Earth = 1): |
A) 100, |
B) 5, |
C) 0.5, D) 0.01 |
|
(b) Material in Mercury’s core: |
A) C+N+O, |
B) Rock, |
C) Fe+Ni, D) H+He |
|
(c) Typical orbit radius of asteroids: |
A) 0.3 AU |
B) 3 AU |
C) 50 AU D) 104 AU |
|
(d) Temperature of Galactic coronal gas: |
A) 2.8 K, |
B) 80 K, |
C) 6000 K, D) 106 K |
|
(e) Disc galaxy without spiral arms: |
A) S0, |
B) Sa, |
C) SBc, D) E7 |
|
(f) Source of the “21 cm line”: |
A) CMBR, |
B) H2, |
C) HII, D) HI |
- Two stars with apparent magnitudes 8 and 9, resp., form a binary system. What is the total apparent magnitude for the binary? A) 1, B) 6, C) 9.4, D) 17
- Ingredient in modern theory for the formation of the planets in the Solar system:
- gravitational waves
- tidal forces from spiral arms
- planetary migration
- accretion of material from the ISM (4 p)
2.
The textbook describes an important result concerning radiative transfer in stellar atmospheres as follows:
“… the specific intensity of radiation at a frequency ? coming out of a stellar atmosphere is approximately equal to the Planck function at a depth of the atmosphere where the optical depth for that frequency ? equals unity.”
Use this result to explain the formation of stellar absorption lines. Under what circumstance can instead emission lines be seen in a stellar spectrum? (2 p)
3.
Assume that you have discovered a planetary system where the most massive planet is a Saturn-sized planet in circular orbit (radius 8 AU) around a Sun-like star.
a.) What is the maximum Doppler shift of the Calcium H line (396.847 nm)?
b.) How far from the centre of the star is the centre of mass of the system?
c.) What is a "hot Jupiter" and explain why there seem to be so many of them?
4.
A 5 solar mass star has moved off the main sequence and is on the “subgiant branch” on its way to the giant branch. Estimate the Kelvin-Helmholtz (KH) timescale for the star (Tfinal = 5010 K, L = 1000 LSun). Compare the KH time scale to the time (350 000 yr) the star spends on the subgiant branch. Why is there a discrepancy with the KH time?
5.The figures below show Hertzsprung-Russell diagrams for the brightest stars and the nearest stars, resp.
a.) Which of the diagrams shows the nearest stars, A or B? Which quantities are given on the two axes (same for both diagrams)?
b.) Explain why one of the diagrams contains mainly main sequence stars, while the other diagram contains only a few main sequence stars. (2 p)
6.This question is about white dwarfs. The relativistic equation of state for a degenerate electron gas can be written ???? = ????????4/3, where the constant ???? ? 1010 if we use SI units.
a.) Use this equation of state, and one or several stellar structure equations, to make a rough
estimate of the mass of a star composed of this type of matter. (2 p) b.) What is this type of stars called? What is the mass you calculated called (your result may differ from the result of detailed calculations)? How has this type of stars indirectly been very important for modern cosmology? (2 p)
7.In certain active galaxies, changes in the position of substructures may be detected over intervals as short as a year. For a quasar at a redshift of z = 0.2, one component is seen to move away from the nucleus with an apparent angular velocity of 1.74 milliarcseconds per year.
a.) What is the corresponding apparent, projected linear velocity of this component?
b.) What is the minimum matter ejection velocity required in order to produce the apparent superluminal speed observed in a.)?
8.a.) Express the critical density of the Universe as a function of the Hubble constant H. (1 p) b.) For a matter dominated flat Universe with ? = 1 and ???????? = 0, calculate age of the Universe as a fraction of the present age (i.e., ????/????0) corresponding to a redshift of ???? = 1. (You may make a reasonable assumption of how the density depends on the scale factor). (3 p) c.) Very early in the history of the Universe ????(????) was proportional to ????1/2. Show that at these very early times, the density parameter ? = ????/???????? was very close to 1. (You may not assume that ???? = 0.) (3 p)
