Confrontation of the ISO spectra with model atmospheres of M-type stars: Dwarfs, giants, and supergiants

T. Tsuji, W. Aoki, K. Ohnaka

Research output: Contribution to journalArticlepeer-review

Abstract

After a brief survey on model atmospheres of M-type stars from dwarfs to supergiants, initial attempts on the confrontation between the predicted spectra based on our models and observed ones by KAO and ISO will be reported. First, a well calibrated spectrum of β Peg by KAO appears to show significant disagreements with the predicted one, especially at the region of H2O bands. A higher resolution spectrum by the ISO SWS clearly shows the presence of H2O bands in this early M giant star, but this can never be explained by the model atmosphere. This fact does not necessarily imply some flaws in the model atmosphere, but H2O bands in β Peg may be nonphotospheric in origin. In such a case, model atmosphere cannot be used for calibration purpose. Second, the overall SEDs of M giants are well consistent with the predictions by our model atmospheres, but the H2O bands appear to be too strong as compared with those predicted. Third, SEDs of M supergiants are also consistent with our model predictions (except for S Per), but early M supergiants show H2O bands that can never be explained by our models as in β Peg. Finally, M dwarfs observed by PHT-S are still in preliminary stage of data reduction, but spectrum of the late M dwarf LHS1070, for example, agrees rather well with the predicted one based on our dusty model rather than on non-dusty model.

Original languageEnglish
Pages (from-to)219-222
Number of pages4
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number419
Publication statusPublished - 1997
Externally publishedYes

Keywords

  • Calibration by model atmosphere
  • Dust in M dwarfs
  • Intensity anomalies of CO, SiO, HO, & CO bands in M giants
  • Origin of HO in early M (super)giants

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

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