# Interstellar Matter

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# General

This course is given by Laurentius Waters in the second semester. It is an obligatory course, given in 13 two hour lectures, some of which extend up to three hours for sake of exercises. The exam is closed book. There are no assignements, tasks, ... whatsoever during the year. The lectures notes are all that is needed to be known for the exam.

# Exams

## 15 June 2010

For scans; see:

Or in short, the wiki version:

Ten terms that needed explaining.

Interstellar Gas

• Describe the dominant heating and cooling processes for HI and HII regions
• Explain the cooling function for hydrogen gas. (the equation was given eq 3.30)
• Derive the equations for thermal instabilities in HI gas
• Wat is cooling coronal gas?

Molecular spectra

• Explain the virba-rotational diagram of H2
• Why has H2 no dipole transitions
• Would HD have dipole transitions?
• Can the exitation temperature of H2 best be determines from the pure rotational lines or from vibra rotational transitions? Why is the difference between the 2 found temperature that big?

Dust

• What is the dominant process to from H2 in the ISM?
• What would that process be in very high density regions?
• What drives the interstellar chemistry in clouds?
• Are the low CO rotational transitions a good tracer of a cold dense molecular cloud? Motivate your answer.
• Derive the accretion timescale for hydrogen on dust particles in a cloud with density ${\displaystyle 1000cm^{-3}}$ when the dust gas ratio is 1 to 100.
• Give a way to from water molecules in the inter stellar gas.