Section 1 Flashcards

1
Q

Do old or new stars emit more x-rays and why?

A

Young stars
Due to the magnetospheric accretion

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2
Q

Where do infrared ray get detected from?

A

Star forming regions which show the older stars around the younger stars and molecular clouds

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3
Q

What are darker regions in the space due to and why?

A

Molecular clouds
They obscure light from stars behind them due to extinction

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4
Q

What does stellar cluster radiation (UV light) do?

A

Strips away diffuse gas, leaving denser regions of molecular clouds -> sometimes leading to star formation

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5
Q

How many magnitudes does a molecular cloud decrease by when a star is formed?

A

6-7 magnitudes

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6
Q

What is turbulence?

A

When nebular gas moves faster than it should

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7
Q

What is turbulence caused by?

A

Stellar winds, supernova shocks and collisions with other clouds
It occurs in interstellar medium

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8
Q

Where does a star accrete gas and dust from?

A

The surrounding protoplanetary disc

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9
Q

Accretion of young stars can be caused from the surrounding disc, what else can it be caused by?

A

magnetic field lines

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10
Q

Is the accretion of jet set linear?

A

No (it is not homogenous)

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11
Q

Where do protostar’s brightness come from?

A

Gravitational collapse

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12
Q

What do jets cause?

A

When jets inject energy into ISM they generate turbulence

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13
Q

How does the circumstellar disc effect the magnetic field of a star?

A

It causes it to twist and become more concentrated around the star leading to jets and molecular clouds

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13
Q

When does spontaneous star formation occur?

A

When there is a drastic drop in temperature (cooling)

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14
Q

What is the HII region?

A

Region with ionised hydrogen occurring around hot massive stars

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14
Q

What does the HII region trigger?

A

Star formation as it exerts high pressure and causes wind blown bubbles

14
Q

In which wavelength can discs be seen?

A

Infrared but not in optical due to low temp of stars

15
Q

What do gaps in the discs seen in the infrared mean?

A

Star formation is underway

16
Q

How does planetary formation occur?

A

Through core accretion or gravitational collapse

17
Q

How do stars form?

A

Via the collapse of cold and dense molecular clouds in the interstellar medium of galaxies

18
Q

What do young hot and bright stars show?

A

Accretion is occurring

19
Q

What do magnetic fields govern>

A

The formation of discs, outflows and jets