Millimeter continuum observations of a massive protostellar core in Sagittarius B2

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/167111· OSTI ID:6394718

Carlstrom, J E; Vogel, S N

The Hat Creek interferometer has been used to map 3.4 mm continuum emission from Sgr B2 with 4.5 x 2 arcsec resolution. The fluxes of two of the detected sources are substantially higher at 3.4 mm than at 1.3 cm; both sources are coincident with centroids of water maser clusters to less than 1 arcsec. In one, the flux can be attributed to free emission with a turnover frequency greater than 23 GHz; in the other, 3.4 mm emission comes mainly from hot dust grains in a dense protostellar core containing two embedded ultracompact H II regions. The amount of molecular material within 0.1 pc of the embedded protostars is at least one order of magnitude greater than within 0.1 pc of any of the other dozen ultracompact H II regions in Sgr B2. The observations indicate that ultracompact H II regions are much more common than the dense cores from which they presumably form, and that they survive long after most of the surrounding gas has been dispersed by outflow. 21 references.

• Research Organization: California Univ., Berkeley (USA); Rensselaer Polytechnic Institute, Troy, NY (USA)
• OSTI ID: 6394718
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 337; ISSN ASJOA
• 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
AMPLIFIERS
COSMIC DUST
COSMIC RADIO SOURCES
DUSTS
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUID FLOW
GAS FLOW
H2 REGIONS
HYDROGEN COMPOUNDS
MAPS
MASERS
MASS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MICROWAVE RADIATION
MOLECULES
OXYGEN COMPOUNDS
PROTOSTARS
RADIATION FLUX
RADIATIONS
STAR EVOLUTION
WATER