A search for Hα absorption in the exosphere of the transiting extrasolar planet HD 209458b

Joshua N. Winn, Yasushi Suto, Edwin L. Turner, Norio Narita, Brenda Louise Frye, Wako Aoki, Bun'ei Sato, Toru Yamada

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

There is evidence that the transiting planet HD 209458h has a large exosphere of neutral hydrogen, based on a 15% decrement in Lyman-α flux that was observed by Vidal-Madjar et al. during transits. Here we report upper limits on Hα absorption by the exosphere. The results are based on optical spectra of the parent star obtained with the Subaru High Dispersion Spectrograph. Comparison of the spectra taken inside and outside of transit reveals no exospheric Hα signal greater than 0.1% within a 5.1 Å band (chosen to have the same Δλ/λ as the 15% Lyα absorption). The corresponding limit on the column density of n = 2 neutral hydrogen is N2 ≲ 109cm-2. This limit constrains proposed models involving a hot (∼ 104K) and hydrodynamically escaping exosphere.

Original languageEnglish (US)
Pages (from-to)655-662
Number of pages8
JournalPublications of the Astronomical Society of Japan
Volume56
Issue number4
StatePublished - 2004
Externally publishedYes

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exosphere
extrasolar planets
planet
hydrogen
transit
high dispersion spectrographs
optical spectrum
planets
stars
comparison

Keywords

  • Planetary systems: individual (HD 209458b)
  • Techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Winn, J. N., Suto, Y., Turner, E. L., Narita, N., Frye, B. L., Aoki, W., ... Yamada, T. (2004). A search for Hα absorption in the exosphere of the transiting extrasolar planet HD 209458b. Publications of the Astronomical Society of Japan, 56(4), 655-662.

A search for Hα absorption in the exosphere of the transiting extrasolar planet HD 209458b. / Winn, Joshua N.; Suto, Yasushi; Turner, Edwin L.; Narita, Norio; Frye, Brenda Louise; Aoki, Wako; Sato, Bun'ei; Yamada, Toru.

In: Publications of the Astronomical Society of Japan, Vol. 56, No. 4, 2004, p. 655-662.

Research output: Contribution to journalArticle

Winn, JN, Suto, Y, Turner, EL, Narita, N, Frye, BL, Aoki, W, Sato, B & Yamada, T 2004, 'A search for Hα absorption in the exosphere of the transiting extrasolar planet HD 209458b', Publications of the Astronomical Society of Japan, vol. 56, no. 4, pp. 655-662.
Winn, Joshua N. ; Suto, Yasushi ; Turner, Edwin L. ; Narita, Norio ; Frye, Brenda Louise ; Aoki, Wako ; Sato, Bun'ei ; Yamada, Toru. / A search for Hα absorption in the exosphere of the transiting extrasolar planet HD 209458b. In: Publications of the Astronomical Society of Japan. 2004 ; Vol. 56, No. 4. pp. 655-662.
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AU - Suto, Yasushi

AU - Turner, Edwin L.

AU - Narita, Norio

AU - Frye, Brenda Louise

AU - Aoki, Wako

AU - Sato, Bun'ei

AU - Yamada, Toru

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