Section 1 Flashcards
Do old or new stars emit more x-rays and why?
Young stars
Due to the magnetospheric accretion
Where do infrared ray get detected from?
Star forming regions which show the older stars around the younger stars and molecular clouds
What are darker regions in the space due to and why?
Molecular clouds
They obscure light from stars behind them due to extinction
What does stellar cluster radiation (UV light) do?
Strips away diffuse gas, leaving denser regions of molecular clouds -> sometimes leading to star formation
How many magnitudes does a molecular cloud decrease by when a star is formed?
6-7 magnitudes
What is turbulence?
When nebular gas moves faster than it should
What is turbulence caused by?
Stellar winds, supernova shocks and collisions with other clouds
It occurs in interstellar medium
Where does a star accrete gas and dust from?
The surrounding protoplanetary disc
Accretion of young stars can be caused from the surrounding disc, what else can it be caused by?
magnetic field lines
Is the accretion of jet set linear?
No (it is not homogenous)
Where do protostar’s brightness come from?
Gravitational collapse
What do jets cause?
When jets inject energy into ISM they generate turbulence
How does the circumstellar disc effect the magnetic field of a star?
It causes it to twist and become more concentrated around the star leading to jets and molecular clouds
When does spontaneous star formation occur?
When there is a drastic drop in temperature (cooling)
What is the HII region?
Region with ionised hydrogen occurring around hot massive stars
What does the HII region trigger?
Star formation as it exerts high pressure and causes wind blown bubbles
In which wavelength can discs be seen?
Infrared but not in optical due to low temp of stars
What do gaps in the discs seen in the infrared mean?
Star formation is underway
How does planetary formation occur?
Through core accretion or gravitational collapse
How do stars form?
Via the collapse of cold and dense molecular clouds in the interstellar medium of galaxies
What do young hot and bright stars show?
Accretion is occurring
What do magnetic fields govern>
The formation of discs, outflows and jets
