Near-infrared spectroscopy of young stellar objects

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5470289

Carr, J S

Near-infrared spectroscopic observations of young stellar objects are presented. Spectra were obtained of the first overtone bands of CO, the hydrogen Br {gamma} line, and the S(1) v = 1-0 line of H{sub 2}. The majority of objects observed have luminosities less than 1000 solar luminosities. The CO overtone bands were found in emission in 6 out of 31 objects. This result, when combined with published data, shows that approximately 20 to 25% of young stellar objects with outflows have CO vibrational band emission. The CO emission requires a neutral gas with CO excitation temperatures of 2500-4000 K. The CO is most likely excited by collisions in gas with densities {ge}10{sup 10} cm{sup {minus}3}. Two models are discussed for producing the CO emission. First, models are calculated for steady-state accretion disks. The radial distribution of temperature in the disk was calculated by balancing the heating and cooling in the disk. The second model considered is a spherical, stellar wind with velocities of 100 to 300 km s{sup {minus}1}. The gas temperature in the wind is assumed to be 3000 K to maximize the CO emission. Thirty objects were measured for Br {gamma} emission. Also reported are four new detections of H{sub 2} emission in young stars. It was verified that the proportionality between hydrogen recombination line strength and stellar luminosity extends down to 1 solar luminosity objects.

• Research Organization: Texas Univ., Austin, TX (USA)
• OSTI ID: 5470289
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
HYDROGEN
INFRARED SPECTRA
LUMINOSITY
MATHEMATICAL MODELS
NONMETALS
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SPECTRA
STAR MODELS
STARS
STELLAR ACTIVITY
STELLAR WINDS
VERY HIGH TEMPERATURE