High-mass star formation within the bright-rimmed cloud SFO 79

Abstract

We report Radio Recombination Line (RRL) and continuum observations toward the IRAS point source 16362--4845, embedded within the Bright-Rimmed Cloud (BRC) SFO 79, a small molecular cloud lying at the edge of the HII region RCW 108. High resolution observations of the H92alpha hydrogen recombination line and of the continuum emission (3.6 and 6 cm) confirm the presence of a resolved Ultra Compact (UC) HII region embedded within the molecular cloud. The integrated radio fluxes suggest the source of the ionisation to be an O9 Zero Age Main Sequence (ZAMS) star. Millimetre observations of 12CO, 13CO and C18O (J=1--0) molecular lines reveal the presence of a molecular condensation offset \~30 arcsec to the north of the IRAS position on the boundary of the UC HII region. Analysis of 2MASS data has led to the identification of a small IR cluster of Young Stellar Objects (YSOs) that are positionally coincident with the UC HII region, lying to the south east of the peak of the radio emission. Moreover, the UC HII region appears to be extended in the direction of the IR cluster, which suggests that the radio emission and the IR cluster are in some way related to each other. MSX 8.3 micron and 21.3 micron images have been used to trace the large scale structure of the BRC, revealing the presence of a Photo Dominated Region (PDR) and three embedded thermal sources within the molecular cloud. The alignment of the three thermal sources along a line parallel to the bright rim suggests that they could have been triggered by the propagation of a plane parallel shock through the cloud.

arXiv comment19 pages, 9 figures, the images in this version are low resolution. High resolution images are available on request from the lead author

References in corpus (5)

• Physical Conditions in Regions of Star Formation
• New infrared star clusters in the southern Milky Way with 2MASS
• Searching for signs of triggered star formation toward IC 1848
• Photodissociation regions and star formation in the Carina Nebula
• A Compact Array imaging survey of southern bright-rimmed clouds

Cited by in corpus (20)

• The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview
• Observational study of sites of triggered star formation: CO and mid-infrared observations
• The statistics of triggered star formation: an overdensity of massive YSOs around Spitzer bubbles
• The HI/OH/Recombination line survey of the inner Milky Way (THOR)
• Radio continuum and molecular line observations of four bright-rimmed clouds
• X-ray and IR Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 108
• A SCUBA survey of bright-rimmed clouds
• Star formation in RCW 108: triggered or spontaneous?
• Triggered star formation surrounding Wolf-Rayet star HD 211853
• Planck cold clumps in the $\lambda$ Orionis complex: I. Discovery of an extremely young Class 0 protostellar object and a proto-brown dwarf candidate in a bright rimmed clump PGCC G192.32-11.88
• Ammonia observations of bright-rimmed clouds: establishing a sample of triggered protostars
• Structural studies of eight bright rimmed clouds in the southern hemisphere
• Assessing molecular line diagnostics of triggered star formation using synthetic observations
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XIII. Ongoing triggered star formation within clump-fed scenario found in the massive ($\sim 1500$ ${\mathrm{M}}_{\odot }$) clump
• H${}_2$O maser emission from bright rimmed clouds in the northern hemisphere
• Star formation in the S233 region
• APEX CO observations towards the photodissociation region of RCW120
• SOAR-OSIRIS observations of the Sh 2-307 HII region: Triggered star formation beyond the solar circle
• Illuminating a tadpole's metamorphosis III: quantifying past and present environmental impact
• Astrophysics in 2005