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Title: YSOVAR: Mid-infrared variability in the star-forming region Lynds 1688

The emission from young stellar objects (YSOs) in the mid-infrared (mid-IR) is dominated by the inner rim of their circumstellar disks. We present IR data from the Young Stellar Object VARiability (YSOVAR) survey of ∼800 objects in the direction of the Lynds 1688 (L1688) star-forming region over four visibility windows spanning 1.6 yr using the Spitzer Space Telescope in its warm mission phase. Among all light curves, 57 sources are cluster members identified based on their spectral energy distribution and X-ray emission. Almost all cluster members show significant variability. The amplitude of the variability is larger in more embedded YSOs. Ten out of 57 cluster members have periodic variations in the light curves with periods typically between three and seven days, but even for those sources, significant variability in addition to the periodic signal can be seen. No period is stable over 1.6 yr. Nonperiodic light curves often still show a preferred timescale of variability that is longer for more embedded sources. About half of all sources exhibit redder colors in a fainter state. This is compatible with time-variable absorption toward the YSO. The other half becomes bluer when fainter. These colors can only be explained with significant changes inmore » the structure of the inner disk. No relation between mid-IR variability and stellar effective temperature or X-ray spectrum is found.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
  3. Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
  4. Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
  5. NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)
  6. Spitzer Science Center/Caltech, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  7. National Optical Astronomy Observatories, Tucson, AZ 85719 (United States)
  8. Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
  9. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  10. Infrared Processing and Analysis Center, California Institute of Technology, MC 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)
  11. Centro de Astrobiología (INTA-CSIC), ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Canada (Spain)
  12. Department of Physics and Astronomy, Georgia State University, 25 Park Place South, Atlanta, GA 30303 (United States)
  13. Physics and Astronomy Department, University of Georgia, Athens, GA 30602-2451 (United States)
Publication Date:
OSTI Identifier:
22342205
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; AMPLITUDES; EMISSION; ENERGY SPECTRA; INFRARED RADIATION; INTERMEDIATE INFRARED RADIATION; PERIODICITY; PROTOSTARS; RESONANCE IONIZATION MASS SPECTROSCOPY; SPACE; STARS; TELESCOPES; VISIBILITY; VISIBLE RADIATION; X RADIATION; X-RAY SPECTRA