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Astron. Astrophys. 364, L13-L18 (2000)

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Letter to the Editor

VLT-detection of two edge-on Circumstellar Disks in the [FORMULA] Oph dark cloud *

W. Brandner 1, S. Sheppard 1, H. Zinnecker 2, L. Close 3, F. Iwamuro 4, A. Krabbe **  5, T. Maihara 4, K. Motohara 6, D.L. Padgett 7 and A. Tokunaga 1

1 University of Hawaii, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA (brandner@ifa.hawaii.edu, sheppard@ifa.hawaii.edu, tokunaga@ifa.hawaii.edu)
2 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany (hzinnecker@aip.de)
3 European Southern Observatory, Karl-Schwarzschild Strasse 2, 85748 Garching, Germany (lclose@eso.org)
4 Kyoto University, Department of Physics, Kitashirakawa, Kyoto 606-8502, Japan (iwamuro@cr.scphys.kyoto-u.ac.jp, maihara@cr.scphys.kyoto-u.ac.jp
5 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Weltraumsensorik und Planetenerkundung, Rutherfordstrasse 2, 12489 Berlin, Germany (krabbe@dlr.de)
6 Subaru Telescope, National Astronomical Observatory of Japan, 650 North A`ohoku Place, Hilo, HI 96720, USA (motohara@subaru.naoj.org)
7 Jet Propulsion Laboratory, IPAC 100-22, California Institute of Technology, Pasadena, CA 91125, USA (dlp@ipac.caltech.edu)

Received 10 August 2000 / Accepted 7 September 2000


Observations of the [FORMULA] Ophiuchi star forming region with VLT ANTU and ISAAC under [FORMULA] seeing conditions reveal two bipolar reflection nebulosities intersected by central dust lanes. The sources (OphE-MM3 and CRBR 2422.8-3423) can be identified as spatially resolved circumstellar disks viewed close to edge-on, similar to edge-on disk sources discovered previously in the Taurus and Orion star forming regions. Millimeter continuum fluxes yield disk masses of the order of 0.01 [FORMULA], i.e. about the mass deemed necessary for the minimum solar nebula. Follow-up spectroscopic observations with SUBARU and CISCO show that both disk sources exhibit featureless continua in the K-band. No accretion or outflow signatures were detected. The slightly less edge-on orientation of the disk around CRBR 2422.8-3423 compared to HH 30 leads to a dramatic difference in the flux seen in the ISOCAM 4.5 µm to 12 µm bands. The observations confirm theoretical predictions on the effect of disk geometry and inclination angle on the spectral energy distribution of young stellar objects with circumstellar disks.

Key words: stars: circumstellar matter – stars: formation – stars: pre-main sequence – Galaxy: open clusters and associations: individual: rho Ophiuchi dark cloud

* Based on observations at the European Southern Observatory, Paranal (ESO Prop ID 63.I-0691), the NAOJ SUBARU telescope at Mauna Kea, Hawai`i, the ESA Infrared Space Observatory, and the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under the NASA contract NAS5-26555.
** new address: University of California at Berkeley, Department of Physics, 366 LeConte Hall #7300, Berkeley, CA 94720-7300, USA

© European Southern Observatory (ESO) 2000

Online publication: December 15, 2000