Molecular outflows and mass loss in pre-main-sequence stars

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5525521

Levreault, R M

A survey was conducted for molecular outflows toward 1 pre-main-sequence stars using the J = 2 ..-->.. 1 transition of CO. Outflows were detected toward 21 of these objects. The outflow sources range in mass from 0.5 to 30 M/sub sun/, in luminosity from 4 to 1.1 x 10/sup 5/ L/sub sun/, and in age from <10/sup 4/ to approx.10/sup 6/ years. In the H-R diagram the outflow sources form a distinct band running across the top of the diagram. In addition to the CO (J = 2 ..-->.. 1) data, we have obtained CO(J = 1 ..-->.. 0) and /sup 13/CO(J = 1 ..-->.. 0) observations which enable us to estimate the excitation temperature and optical depth in each outflow, leading to the derivation of outflow masses. The observed outflows range in age from approx.10/sup 3/ to 5 x 10/sup 5/ years old, and have masses from 0.01 to 56 M/sub sun/. Simple momentum conservation arguments are then used to deduce the mass loss necessary to produce the observed outflows; the results range from 9 x 10/sup -9/ to 8 x 10/sup -4/ M/sub sun/ yr/sup -1/. The observed pre-main-sequence winds could have important consequences for planetary formation, particularly of the terrestrial planets. Quantitative tests of self-regulated low-mass star formation suggest that this mechanism can support a 100 M/sub sun/ molecular cloud against collapse for 50 million years. Such a lifetime can explain the observed age spread in nearby star forming regions.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 5525521
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics &amp; Cosmology-- Stars &amp; Quasi-Stellar
Radio &amp; X-Ray Sources
640107 -- Astrophysics &amp; Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
LOSSES
LUMINOSITY
MASS
MOLECULES
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLANET-SYSTEM ACCRETION
STAR EVOLUTION
STARS