Letter to the Editor

Hier ist wahrhaftig ein Loch im Himmel ^*,**,***

The NGC 1999 dark globule is not a globule

¹ ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany e-mail: tstanke@eso.org
² Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
³ Department of Astronomy and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
⁴ Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
⁵ NASA Herschel Science Center, California Institute of Technology, 770 South Wilson Ave, Pasadena, CA91125, USA
⁶ Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
⁷ National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719, USA
⁸ Department of Physics and Astronomy, University of Victoria, PO Box 355, STN CSC, Victoria BC, V8W 3P6, Canada
⁹ National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria BC, V9E 2E7, Canada
¹⁰ JPL, California Institute of Technology, Mail Stop 264767, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
¹¹ Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA
¹² Laboratoire d'Astrophysique de Grenoble, Université Joseph Fourier, CNRS, UMR 571, BP 53, 38041 Grenoble, France
¹³ Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA
¹⁴ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹⁵ Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
¹⁶ Instituto de Astrofisica de Andalucia, CSIC, Camino Bajo de Huetor 50, 18008, Granada, Spain
¹⁷ Division of Geological and Planetary Sciences 150-21, California Institute of Technology, Pasadena, CA 91125, USA

Received: 31 March 2010
Accepted: 3 May 2010

Abstract

The NGC 1999 reflection nebula features a dark patch with a size of ~10 000 AU, which has been interpreted as a small, dense foreground globule and possible site of imminent star formation. We present Herschel PACS far-infrared 70 and 160 μm maps, which reveal a flux deficit at the location of the globule. We estimate the globule mass needed to produce such an absorption feature to be a few tenths to a few . Inspired by this Herschel observation, we obtained APEX LABOCA and SABOCA submillimeter continuum maps, and Magellan PANIC near-infrared images of the region. We do not detect a submillimer source at the location of the Herschel flux decrement; furthermore our observations place an upper limit on the mass of the globule of ~2.4×10^-2 . Indeed, the submillimeter maps appear to show a flux depression as well. Furthermore, the near–infrared images detect faint background stars that are less affected by extinction inside the dark patch than in its surroundings. We suggest that the dark patch is in fact a hole or cavity in the material producing the NGC 1999 reflection nebula, excavated by protostellar jets from the V 380 Ori multiple system.