Protostars in the Elephant Trunk Nebula
Abstract
The optically-dark globule IC 1396A is revealed using Spitzer images at 3.6, 4.5, 5.8, 8, and 24 microns to be infrared-bright and to contain a set of previously unknown protostars. The mid-infrared colors of the 24 microns detected sources indicate several very young (Class I or 0) protostars and a dozen Class II stars. Three of the new sources (IC 1396A: gamma, delta, and epsilon) emit over 90% of their bolometric luminosities at wavelengths greater than 3 microns, and they are located within ~0.02 pc of the ionization front at the edge of the globule. Many of the sources have spectra that are still rising at 24 microns. The two previously-known young stars LkHa 349 a and c are both detected, with component c harboring a massive disk and component a being bare. Of order 5% of the mass of material in the globule is presently in the form of protostars in the 10^5 to 10^6 yr age range. This high star formation rate was likely triggered by radiation from a nearby O star.
Keywords
Cite
@article{arxiv.astro-ph/0406308,
title = {Protostars in the Elephant Trunk Nebula},
author = {William T. Reach and Jeonghee Rho and Erick Young and James Muzerolle and Sergio Fajardo-Acosta and Lee Hartmann and Aurora Sicilia-Aguilar and Lori Allen and Sean Carey and Jean-Charles Cuillandre and Thomas H. Jarrett and Patrick Lowrance and Anthony Marston and Alberto Noriega-Crespo and Robert L. Hurt},
journal= {arXiv preprint arXiv:astro-ph/0406308},
year = {2008}
}
Comments
Spitzer first ApJS special issue (in press)