infrared studies of massive star formation
DESCRIPTION
Infrared Studies of Massive Star Formation. by Claudia Knez. Outline. What is star formation? Why study the star formation using infrared radiation and not visible light? Why SOFIA is important for our observations?. Star Formation. - PowerPoint PPT PresentationTRANSCRIPT
by
Claudia Knez
Outline
• What is star formation?
• Why study the star formation using infrared radiation and not visible light?
• Why SOFIA is important for our
observations?
Star Formation• Large clouds of cold, dense gas
(molecular clouds) collapse to form stars.
• Cold gas means temperature T~10–50 K
0 oC = 273 K• Stars of different masses form in
these regions.• Massive stars do not form in
isolation. • As the clouds collapse and stars
begin to form, the temperature of the gas and dust rises.
From Stars to Planets
• Chemical studies in star forming regions reveal the composition of the gas.
• Planets form from gas around stars.• Comets have similar composition as
the interstellar medium.
•Are organic molecules common in star forming regions?
Dust
• At low temperatures, the gas freezes onto dust grains.
• Chemical reactions occurs on the surface of grains.
• As gas is heated by protostars, the ice is evaporated from the dust grains.
Gas
• Newly evaporated molecules such as acetylene, C2H2, and methane, CH4, are observed.
• These and other complex organic molecules are seen towards protostars.
• The molecules necessary for life seem to be COMMON!
Why Study Protostars in the Infrared?
• Gas around forming stars is dense and it traps light from protostars.
• The gas and dust heat up and re-emit the light at longer wavelength (infrared and radio).
• Molecules along the line of sight absorb the light and create an absorption spectrum.
• Visible light does not get through the cloud!
Absorption SpectrumAbsorption spectrum
Continuum spectrum Emission spectrum
Challenge of Infrared Astronomy
EARTH’S
ATMOSPHERE ! !
Infrared Water Vapor Image
Hurricane in Infrared
Earth’s atmosphere at 16.7 microns
Earth’s Atmosphere at 11.9 microns
Absorbers in Atmosphere
• Main absorbers in the atmosphere are:– Water– Carbon dioxide– Ozone
• Other absorbers include:– Methane
Ground telescope
SOFIA
Space Observatory
SOFIA
• SOFIA will fly above most of the troposphere
• Absorption by most atmospheric molecules will be decreased.
• The study of molecules such as water and methane will be possible!
Telescope