Lecture 21 - The Interstellar Medium and Star Formation

Question 1

How are stars formed?

Answer 1

By gravitational collapse in molecular clouds

Question 2

What are T-Tauri stars?

Answer 2

Young, not so massive stars with variable luminosity, IR excess and strong X-ray emission

Question 3

The spectral classification scheme of young stellar objects (YSOs) are class 0 - III. Which is the youngest?

Answer 3

class 0

Question 4

Speed of bipolar protostellar outflow

Answer 4

v>100 km/s

Question 5

What proportion of milky way galaxy stars are binaries?

Answer 5

About half

Question 6

Explain the Jeans swindle

Answer 6

Jeans analysis is only first order pertubation equations. The zeroth order implies rho_0=0 which is unphysical

Question 7

What is the magnetic field problem?

Answer 7

That the collapsing core must lose magnetic flux

Question 8

When do B-field stop collapse of stellar formation?

Answer 8

When M < Magnetically critical mass

Question 9

What is the angular momentum problem?

Answer 9

Clumps must be able to lose their angular momentum if star formation
is to take place