Infrared studies of epsilon Aurigae in eclipse

Robert E. Stencel, Brian K. Kloppenborg, Randall E. Wall, Jeffrey L. Hopkins, Steve B. Howell, D. W. Hoard, John Rayner, Schelte Bus, Alan Tokunaga, Michael L. Sitko, Suellen Bradford, Ray W. Russell, David K. Lynch, Heidi Hammel, Barbara Whitney, Glenn Orton, Padma Yanamandra-Fisher, Joseph L. Hora, Philip Hinz, William HoffmannAndrew Skemer

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


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 57days after nominal mid-eclipse, but was not detected at mid-eclipse plus 34days, 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 90days 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.

Original languageEnglish (US)
Article number174
JournalAstronomical Journal
Issue number5
StatePublished - Nov 2011


  • binaries: eclipsing
  • protoplanetary disks
  • stars: individual (epsilon Aurigae)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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