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Title: THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Max Planck Institute for Astronomy Königstuhl 17, Heidelberg D-69117 (Germany)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  3. Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States)
  4. Natinal Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
  5. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  6. Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands)
  7. CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States)
  8. Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest (Hungary)
Publication Date:
OSTI Identifier:
22365640
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 789; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; CAMERAS; FAR INFRARED RADIATION; FREQUENCY DEPENDENCE; IMAGES; INFRARED SPECTRA; PERIODICITY; PHOTOMETRY; PROTOSTARS; SPECTROMETERS; STAR ACCRETION; STARS; VISIBLE RADIATION; WAVELENGTHS