The stellar population and complex structure of the bright-rimmed cloud IC 1396N^*

¹ Universitat de Barcelona, Departament d'Astronomia i Meteorologia, Unitat Associada a CSIC, Martí i Franquès 1, 08028 Barcelona, Catalunya, Spain e-mail: mbeltran@am.ub.es
² INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
³ Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalunya, Spain
⁴ Institut de Ciències de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ciències, Torre C-5, 08193 Bellaterra, Catalunya, Spain

Received: 17 December 2008
Accepted: 23 February 2009

Abstract

Context. IC 1396N is a bright-rimmed cloud associated with an intermediate-mass star-forming region, where a number of Herbig-Haro objects, H₂ jet-like features, CO molecular outflows, and millimeter compact sources have been observed.

Aims. We study the complex structure of the IC 1396N core and the molecular outflows detected in the region in detail and reveal the presence of additional YSOs inside this globule.

Methods. We carried out a deep survey of the IC 1396N region in the broadband filters and deep high-angular resolution observations in the H₂ narrowband filter with NICS at the TNG telescope. The completeness limits in the 2MASS standard are , , and .

Results. A total of 736 sources have been detected in all three bands within the area where the JHK' images overlap. There are 128 sources detected only in HK', 67 detected only in K', and 79 detected only in JH. We found only a few objects exhibiting a near-infrared excess and no clear signs of clustering of sources towards the southern rim. In the case of triggered star formation in the southern rim of the globule, this could be very recent, because it is not shown through Near-Infrared imaging alone. The H₂ emission is complex and knotty and shows a large number of molecular hydrogen features spread over the region, testifying to recent star-formation activity throughout the whole globule. This emission is resolved into several chains or groups of knots that sometimes show a jet-like morphology. The shocked cloudlet model scenario previously proposed to explain the V-shaped morphology of the CO molecular outflow powered by the intermediate-mass YSO BIMA 2 seems to be confirmed by the presence of H₂ emission at the position of the deflecting western clump. New possible flows have been discovered in the globule, and some of them could be very long. In particular, the YSO BIMA 3 could be powering an old and poorly collimated outflow.