Volume 531, July 2011
|Number of page(s)||13|
|Section||Stellar structure and evolution|
|Published online||06 June 2011|
Sequential star formation in IRAS 06084-0611 (GGD 12-15)
Astronomical Institute Anton Pannekoek, University of Amsterdam, PO Box 94249, 1090 GE Amsterdam, The Netherlands
2 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
3 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
4 SRON-Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
5 Centro de Astrobiología (CSIC-INTA), 28850 Torrejón de Ardoz, Madrid, Spain
6 Instituut voor Sterrenkunde, Celestijnenlaan 200D, 3001 Leuven, Belgium
7 I.Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
Received: 17 February 2011
Accepted: 21 April 2011
Context. The formation and early evolution of high- and intermediate-mass stars towards the main sequence involves the interplay of stars in a clustered and highly complex environment. To obtain a full census of this interaction, the Formation and Early evolution of Massive Stars (FEMS) collaboration studies a well-selected sample of 10 high-mass star-forming regions.
Aims. In this study we examine the stellar content of the high-mass star-forming region centered on IRAS 06084-0611 in the Monoceros R2 cloud.
Methods. Using the near-infrared H- and K-band spectra from the VLT/SINFONI instrument on the ESO Very Large Telescope (VLT) and photometric near-infrared NTT/SOFI, 2MASS and Spitzer/IRAC data, we were able to determine the spectral types for the most luminous stars in the cluster.
Results. Two very young and reddened massive stars have been detected by SINFONI: a massive young stellar object (YSO) consistent with an early-B spectral type and a Herbig Be star. Furthermore, stars of spectral type G and K are detected while still in the Pre-Main Sequence (PMS) phase. We derive additional properties such as temperatures, extinctions, radii and masses. We present a Hertzsprung-Russell diagram and find most objects having intermediate masses between ~1.5–2.5 M⊙. For these stars we derive a median cluster age of ~4 Myr.
Conclusions. Using Spitzer/IRAC data we confirm earlier studies that the younger class 0/I objects are centrally located while the class II objects are spread out over a larger area, with rough scale size radii of ~0.5 pc and ~1.25 pc respectively. Moreover, the presence of a massive YSO, an ultracompact H ii region and highly reddened objects in the center of the cluster suggest a much younger age of <1 Myr. A possible scenario for this observation would be sequential star formation along the line of sight; from a cluster of intermediate-mass to high-mass stars.
Key words: infrared: stars / stars: early-type / stars: formation / stars: pre-main sequence / circumstellar matter
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.