* Astronomy

Title: The Spitzer c2d Survey of Nearby Dense Cores: III: Low Mass Star Formation in a Small Group, L1251B
Authors: Jeong-Eun Lee, James Di Francesco, Shih-Ping Lai, Tyler L. Bourke, Neal J. Evans II, Bill Spiesman, Philip C. Myers, Lori E. Allen, Timothy Y. Brooke, Alicia Porras, Zahed Wahhaj

Researchers present a comprehensive study of a low-mass star-forming region, L1251B, at wavelengths from the near-infrared to the millimetre. L1251B, where only one protostar, IRAS 22376+7455, was known previously, is confirmed to be a small group of protostars based on observations with the Spitzer Space Telescope.
The most luminous source of L1251B is located 5" north of the IRAS position. A near-infrared bipolar nebula, which is not associated with the brightest object and is located at the southeast corner of L1251B, has been detected in the IRAC bands. OVRO and SMA interferometric observations indicate that the brightest source and the bipolar nebula source in the IRAC bands are deeply embedded disk sources.
Submillimeter continuum observations with single-dish telescopes and the SMA interferometric observations suggest two possible prestellar objects with very high column densities. Outside of the small group, many young stellar object candidates have been detected over a larger region of 12' x 12'. Extended emission to the east of L1251B has been detected at 850 micron; this "east core" may be a site for future star formation since no point source has been detected with IRAC or MIPS.
This region is therefore a possible example of low-mass cluster formation, where a small group of pre- and protostellar objects (L1251B) is currently forming, alongside a large starless core (the east core).


The Digitised Sky Survey (DSS) R-band image of L1251E.
The box indicates the field of view of the image below and the circles indicate Ha stars from Kun & Prusti (1993).


Position(2000): RA 39:00:00.0 Dec 75:10:00.0
Three-colour composite SST image of L1251E. The IRAC 3.6, 4.5, and 8.0 µm data are presented respectively as blue, green, and red. The small box represents the position of IRAS 22376+7455 and the large box includes the Herbig-Haro (HH) object, HH 373. The circles denote the same Ha stars shown above. The H star with the black box seems consistent with IRS3 (Figure 9). The red spiral galaxy located at (22h40m54.6s, +75.09'52.5'') is UGC 12160 (Cotton et al. 1999). The white line, which is in the direction of SE-NW and centred around IRSA 22376+7455, indicates a jet-like feature, 0.3 pc long.


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-- Edited by Blobrana at 02:43, 2006-05-23