INFRARED STUDIES OF EPSILON AURIGAE IN ECLIPSE

Journal Article · Tue Nov 15 00:00:00 EST 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/142/5/174· OSTI ID:22034356

Stencel, Robert E; Kloppenborg, Brian K; Wall, Randall E ^[1]; Hopkins, Jeffrey L ^[2]; Howell, Steve B ^[3]; Hoard, D W ^[4]; Rayner, John; Bus, Schelte; Tokunaga, Alan ^[5]; Sitko, Michael L; Bradford, Suellen ^[6]; Russell, Ray W; Lynch, David K ^[7]; Hammel, Heidi; Whitney, Barbara ^[8]; Orton, Glenn; Yanamandra-Fisher, Padma ^[9]; Hora, Joseph L ^[10]; Hinz, Philip; Hoffmann, William ^[11] ; others, and

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1. Department of Physics and Astronomy, University of Denver, Denver, CO 80208 (United States)
2. Hopkins Phoenix Observatory, Phoenix, AZ 85033 (United States)
3. National Optical Astronomy Observatories, Tucson, AZ 85719 (United States)
4. Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
5. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
6. Department of Physics, Cincinnati University, Cincinnati, OH (United States)
7. Aerospace Corporation, Los Angeles, CA 90009 (United States)
8. Space Science Institute, Boulder, CO 80301 (United States)
9. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
10. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
11. Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

We report here on a series of medium resolution spectro-photometric observations of the enigmatic long period eclipsing binary epsilon Aurigae, during its eclipse interval of 2009-2011, using near-infrared spectra obtained with SpeX on the Infrared Telescope Facility (IRTF), mid-infrared spectra obtained with BASS on AOES and IRTF, MIRSI on IRTF, and MIRAC4 on the MMT, along with mid-infrared photometry using MIRSI on IRTF and MIRAC4 on the MMT, plus 1995-2000 timeframe published photometry and data obtained with Denver's TNTCAM2 at WIRO. The goals of these observations included: (1) comparing eclipse depths with prior eclipse data, (2) confirming the re-appearance of CO absorption bands at and after mid-eclipse, associated with sublimation in the disk, (3) seeking evidence for any mid-infrared solid state spectral features from particles in the disk, and (4) providing evidence that the externally irradiated disk has azimuthal temperature differences. IR eclipse depths appear similar to those observed during the most recent (1983) eclipse, although evidence for post-mid-eclipse disk temperature increase is present, due to F star heated portions of the disk coming into view. Molecular CO absorption returned 57 days after nominal mid-eclipse, but was not detected at mid-eclipse plus 34 days, narrowing the association with differentially heated sub-regions in the disk. Transient He I 10830A absorption was detected at mid-eclipse, persisting for at least 90 days thereafter, providing a diagnostic for the hot central region. The lack of solid-state features in Spitzer Infrared Spectrograph, BASS, and MIRAC spectra to date suggests the dominance of large particles (micron-sized) in the disk. Based on these observations, mid-infrared studies out of eclipse can directly monitor and map the disk thermal changes, and better constrain disk opacity and thermal conductivity.

• OSTI ID: 22034356
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 142, Issue 5; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION SPECTROSCOPY
ASTRONOMY
ASTROPHYSICS
CARBON MONOXIDE
ECLIPSE
INFRARED SPECTRA
OPACITY
PHOTOMETRY
PROTOPLANETS
RESOLUTION
STARS
SUBLIMATION
TELESCOPES
THERMAL CONDUCTIVITY
TRANSIENTS