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Title: THE BRIGHTENING OF Re50N: ACCRETION EVENT OR DUST CLEARING?

Abstract

The luminous Class I protostar HBC 494, embedded in the Orion A cloud, is associated with a pair of reflection nebulae, Re50 and Re50N, which appeared sometime between 1955 and 1979. We have found that a dramatic brightening of Re50N has taken place sometime between 2006 and 2014. This could result if the embedded source is undergoing a FUor eruption. However, the near-infrared spectrum shows a featureless very red continuum, in contrast to the strong CO bandhead absorption displayed by FUors. Such heavy veiling, and the high luminosity of the protostar, is indicative of strong accretion but seemingly not in the manner of typical FUors. We favor the alternative explanation that the major brightening of Re50N and the simultaneous fading of Re50 is caused by curtains of obscuring material that cast patterns of illumination and shadows across the surface of the molecular cloud. This is likely occurring as an outflow cavity surrounding the embedded protostar breaks through to the surface of the molecular cloud. Several Herbig–Haro objects are found in the region.

Authors:
; ;  [1];  [2];  [3];  [4];  [5];  [6]
  1. Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, HI 96720 (United States)
  2. Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States)
  3. Gemini Observatory, Casilla 603, La Serena (Chile)
  4. Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States)
  5. Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  6. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)
Publication Date:
OSTI Identifier:
22522398
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 805; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CARBON MONOXIDE; CLOUDS; ERUPTION; HERBIG-HARO OBJECTS; ILLUMINANCE; INFRARED SPECTRA; LUMINOSITY; MASS; NEAR INFRARED RADIATION; NEBULAE; PROTOSTARS; REFLECTION; STARS; SURFACES

Citation Formats

Chiang, Hsin-Fang, Reipurth, Bo, Connelley, Michael S., Walawender, Josh, Pessev, Peter, Geballe, T. R., Best, William M. J., and Paegert, Martin, E-mail: hchiang@ifa.hawaii.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: joshw@naoj.org, E-mail: pessev@gmail.com, E-mail: tgeballe@gemini.edu, E-mail: wbest@ifa.hawaii.edu, E-mail: martin.paegert@vanderbilt.edu. THE BRIGHTENING OF Re50N: ACCRETION EVENT OR DUST CLEARING?. United States: N. p., 2015. Web. doi:10.1088/0004-637X/805/1/54.
Chiang, Hsin-Fang, Reipurth, Bo, Connelley, Michael S., Walawender, Josh, Pessev, Peter, Geballe, T. R., Best, William M. J., & Paegert, Martin, E-mail: hchiang@ifa.hawaii.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: joshw@naoj.org, E-mail: pessev@gmail.com, E-mail: tgeballe@gemini.edu, E-mail: wbest@ifa.hawaii.edu, E-mail: martin.paegert@vanderbilt.edu. THE BRIGHTENING OF Re50N: ACCRETION EVENT OR DUST CLEARING?. United States. doi:10.1088/0004-637X/805/1/54.
Chiang, Hsin-Fang, Reipurth, Bo, Connelley, Michael S., Walawender, Josh, Pessev, Peter, Geballe, T. R., Best, William M. J., and Paegert, Martin, E-mail: hchiang@ifa.hawaii.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: joshw@naoj.org, E-mail: pessev@gmail.com, E-mail: tgeballe@gemini.edu, E-mail: wbest@ifa.hawaii.edu, E-mail: martin.paegert@vanderbilt.edu. Wed . "THE BRIGHTENING OF Re50N: ACCRETION EVENT OR DUST CLEARING?". United States. doi:10.1088/0004-637X/805/1/54.
@article{osti_22522398,
title = {THE BRIGHTENING OF Re50N: ACCRETION EVENT OR DUST CLEARING?},
author = {Chiang, Hsin-Fang and Reipurth, Bo and Connelley, Michael S. and Walawender, Josh and Pessev, Peter and Geballe, T. R. and Best, William M. J. and Paegert, Martin, E-mail: hchiang@ifa.hawaii.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: joshw@naoj.org, E-mail: pessev@gmail.com, E-mail: tgeballe@gemini.edu, E-mail: wbest@ifa.hawaii.edu, E-mail: martin.paegert@vanderbilt.edu},
abstractNote = {The luminous Class I protostar HBC 494, embedded in the Orion A cloud, is associated with a pair of reflection nebulae, Re50 and Re50N, which appeared sometime between 1955 and 1979. We have found that a dramatic brightening of Re50N has taken place sometime between 2006 and 2014. This could result if the embedded source is undergoing a FUor eruption. However, the near-infrared spectrum shows a featureless very red continuum, in contrast to the strong CO bandhead absorption displayed by FUors. Such heavy veiling, and the high luminosity of the protostar, is indicative of strong accretion but seemingly not in the manner of typical FUors. We favor the alternative explanation that the major brightening of Re50N and the simultaneous fading of Re50 is caused by curtains of obscuring material that cast patterns of illumination and shadows across the surface of the molecular cloud. This is likely occurring as an outflow cavity surrounding the embedded protostar breaks through to the surface of the molecular cloud. Several Herbig–Haro objects are found in the region.},
doi = {10.1088/0004-637X/805/1/54},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 805,
place = {United States},
year = {2015},
month = {5}
}