Stellar and molecular radii of a Mira star: First observations with the Keck Interferometer grism

J. A. Eisner, J. R. Graham, R. L. Akeson, E. R. Ligon, M. M. Colavita, G. Basri, K. Summers, S. Ragland, A. Booth

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Using a new grism at the Keck Interferometer, we obtained spectrally dispersed (R ∼ 230) interferometric measurements of the Mira star R Vir. These data show that the measured radius of the emission varies substantially from 2.0 to 2.4 μm. Simple models can reproduce these wavelength-dependent variations using extended molecular layers, which absorb stellar radiation and reemit it at longer wavelengths. Because we observe spectral regions with and without substantial molecular opacity, we determine the stellar photospheric radius, uncontaminated by molecular emission. We infer that most of the molecular opacity arises at approximately twice the radius of the stellar photosphere.

Original languageEnglish (US)
Pages (from-to)L77-L80
JournalAstrophysical Journal
Volume654
Issue number1 II
DOIs
StatePublished - Jan 1 2007

Keywords

  • Circumstellar matter
  • Instrumentation: interferometers
  • Stars: AGB and post-AGB
  • Stars: individual (R Virginis)
  • Techniques: interferometric
  • Techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Eisner, J. A., Graham, J. R., Akeson, R. L., Ligon, E. R., Colavita, M. M., Basri, G., Summers, K., Ragland, S., & Booth, A. (2007). Stellar and molecular radii of a Mira star: First observations with the Keck Interferometer grism. Astrophysical Journal, 654(1 II), L77-L80. https://doi.org/10.1086/510717