Bipolar CO Outflow Research Articles

U-shaped outflow in the LYNDS 1221 dark cloud - an example of interaction of outflows with ambient molecular clouds

Molecular line observations of the dark cloud L1221 in the J = 1-0 transitions of CO, 13 CO, C 18 O, HCO + , HCN, and CS with angular resolutions of 17″-2.7' are presented. A bipolar CO outflow associated with IRAS 22266+6845 have been discovered. The outflow shows a remarkably bent U-shaped structure. The present observations show rather clear evidence for interaction of the outflow with the ambient molecular gas; the ambient gas shows density depression and velocity shift just toward the blue lobe of the outflow. This fact indicates the acceleration and exclusion of the ambient gas by the outflow.

The exciting source of the bipolar outflow in L1448

A fast (+ or - 70 km/s), highly collimated CO bipolar outflow has been recently detected in the L1448 molecular cloud. No optical or infrared object has been found near the center of the outflow, implying a bolometric luminosity less than 3 solar luminosities for the exciting source. The VLA detected, at 2-cm wavelength, a radio continuum source at the center of this outflow. This radio source may be the exciting source of the bipolar outflow. The spectral index of the main component is alpha of about 0.2, similar to that expected for a thermal jet. The second component has a spectral index of alpha of about 1.0, consistent with that of a partially thick H II region. 18 refs.

Jets and bullets in S140

view Abstract Citations (21) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Jets and Bullets in S140 Schwartz, P. R. Abstract High-resolution radio continuum maps of S140 in the vicinity of the embedded star cluster (IRS 1, 2 and 3) show evidence for intrinsic collimation of the outflow. The IRS 1 radio source consists of a core source with a jetlike appendage. The jet points to an extended radio source which may be a radio Herbig-Haro object. This suggests ejection of an interstellar bullet of material from IRS 1. The direction of ejection is approximately perpendicular to the CO bipolar outflow axis. Radio emission was also detected from IRS 2 and 3. Both objects are doubles with thermal spectra. Publication: The Astrophysical Journal Pub Date: March 1989 DOI: 10.1086/185392 Bibcode: 1989ApJ...338L..25S Keywords: Pre-Main Sequence Stars; Radio Jets (Astronomy); Stellar Winds; B Stars; Interstellar Matter; Radio Sources (Astronomy); RESEARCH AND SUPPORT FACILITIES (AIR); INFRARED: SOURCES; STARS: PRE--MAIN-SEQUENCE; STARS: RADIO RADIATION; STARS: WINDS full text sources ADS | data products SIMBAD (4)

Interferometric observations of the 1-0 transition of HCO(+) toward NGC 7538 IRS 1

Interferometric observations of the molecular cloud toward the compact H II region IRS 1 in NGC 7538 in the 1-0 line of HCO(+) are reported. Employing a resolution of 8.5 arcsec, a highly elongated molecular cloud oriented at position angle 52 deg is found, perpendicular to the axis of the bipolar CO outflow. In perfect alignment with the blueshifted lobe in CO, strong blueshifted line wings are detected in HCO(+). The origin of the flow is at the center of the HCO(+) cloud, 15 arcsec to the south of IRS 1, which is clearly not the source that powers this outflow. So far no other indication of star formation has been detected at this position. 8 references.

Neutral stellar winds that drive bipolar outflows in low-mass protostars

The Arecibo radio telescope at the 21-cm line of atomic hydrogen has been used to detect a neutral atomic wind in the bipolar flow source HH 7-11. An atomic mass of about 0.015 solar associated with the rapidly flowing gas is deduced. The stellar mass-loss rate is roughly 3 x 10 to the -6th solar mass/yr if the crossing time of the decelerating wind is 5000 yr. The excess emission in the H I line core gives a total duration of the outflow of about 70,000 yr. A detailed analysis of the H I line shape yields a reasonable deceleration rate for the atomic wind if the stellar wind continuously entrains ambient molecular gas as it propagates from the protostar. A stellar wind with the described characteristics and a terminal velocity of 170 km/s would be more than sufficient to drive the known extended CO bipolar outflow in HH 7-11.

An infrared study of the bipolar outflow region GGD 12-15

Infrared observations from 1 to 100 microns are presented for the region associated with a bipolar CO outflow source near the nebulous objects GGD 12 to 15. A luminous far-infrared source was found associated with a radio-continuum source in the area. This object appears to be a compact HII region around a nearly main-sequence BO star. A faint 20 micron source was also discovered at the position of an H2O maser 3O deg northwest of the HII region. This object appears to be associated with but not coincident with a 2 micron reflection nebula. This structure serves as evidence for a non-spherically symmetric, possibly disk-like dust distribution around the exciting star for the maser. This object probably powers the bi-polar CO outflow although its luminosity is less than 10% that of the star which excites the compact HII region. A number of other 2 micron sources found in the area are probably members of a recently formed cluster.

Detection of bipolar CO outflow in Orion

view Abstract Citations (121) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of bipolar CO outflow in Orion. Erickson, N. R. ; Goldsmith, P. F. ; Snell, R. L. ; Berson, R. L. ; Huguenin, G. R. ; Ulich, B. L. ; Lada, C. J. Abstract The Multiple Mirror Telescope was used as a phase coherent array to map the CO J = 3-2 emission from the central 1 arcmin region of the Orion molecular cloud. The angular resolution was 26 arcsec and the absolute pointing accuracy was better than 5 arcsec. The peak radiation temperature of the high-velocity gas is approximately 75 K, and the characteristic size of the emission region is 30-40 arcsec. The centroid of the high-velocity emission is located roughly 10 arcsec northeast of IRc2. The peaks in the emission strength of the redshifted and blueshifted high-velocity CO are offset with the redshifted emission peaking east and the blueshifted emission peaking north of IRc2. The axis of the high-velocity CO emission is aligned with the two maxima of the 2 micron H2 emission suggesting that the CO is participating in the same bipolar outflow. Publication: The Astrophysical Journal Pub Date: October 1982 DOI: 10.1086/183897 Bibcode: 1982ApJ...261L.103E Keywords: Astronomical Maps; Carbon Monoxide; Emission Spectra; Interstellar Gas; Molecular Clouds; Orion Nebula; Angular Resolution; Antenna Arrays; Astronomical Spectroscopy; Phase Coherence; Red Shift; Telescopes; Astrophysics full text sources ADS | data products SIMBAD (3)