Enstatite-rich warm debris dust around HD165014

Hideaki Fujiwara, Takashi Onaka, Daisuke Ishihara, Takuya Yamashita, Misato Fukagawa, Takao Nakagawa, Hirokazu Kataza, Takafumi Ootsubo, Hiroshi Murakami

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

We present the Spitzer/Infrared Spectrograph spectrum of the main-sequence star HD165014, which is a warm (≳200K) debris disk candidate discovered by the AKARI All-Sky Survey. The star possesses extremely large excess emission at wavelengths longer than 5 μm. The detected flux densities at 10 and 20 μm are ∼ 10 and 30 times larger than the predicted photospheric emission, respectively. The excess emission is attributable to the presence of circumstellar warm dust. The dust temperature is estimated as 300-750K, corresponding to the distance of 0.7-4.4AU from the central star. Significant fine-structured features are seen in the spectrum and the peak positions are in good agreement with those of crystalline enstatite. Features of crystalline forsterite are not significantly seen. HD165014 is the first debris disk sample that has enstatite as a dominant form of crystalline silicate rather than forsterite. Possible formation of enstatite dust from differentiated parent bodies is suggested according to the solar system analog. The detection of an enstatite-rich debris disk in the current study suggests the presence of large bodies and a variety of silicate dust processing in warm debris disks.

Original languageEnglish
Pages (from-to)L152-L156
JournalAstrophysical Journal Letters
Volume714
Issue number1 PART 2
DOIs
Publication statusPublished - 2010

Keywords

  • Circumstellar matter
  • Infrared: stars
  • Planetary systems
  • Stars: individual (HD165014)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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