Near-infrared spectroscopic search for the close orbiting planet HD 75289b

J. R. Barnes, C. J. Leigh, H. R. A. Jones, T. S. Barman, D. J. Pinfield, Andrew Collier Cameron, J. S. Jenkins

Research output: Contribution to journalArticlepeer-review

Abstract

We present a search for the near-infrared spectroscopic signature of the close orbiting extrasolar giant planet HD 75289b. We obtained ∼230 spectra in the wavelength range 2.18–2.19 μm using the Phoenix spectrograph at Gemini South. By considering the direct spectrum, derived from irradiated model atmospheres, we search for the absorption profile signature present in the combined star and planet light. Since the planetary spectrum is separated from the stellar spectrum at most phases, we apply a phase-dependent orbital model and tomographic techniques to search for absorption signatures.

Because the absorption signature lies buried in the noise of a single exposure we apply a multiline deconvolution to the spectral lines available in order to boost the effective signal-to-noise ratio (S/N) of the data. The wavelength coverage of 80 Å is expected to contain ∼100 planetary lines, enabling a mean line with S/N of 800 to be achieved after deconvolution. We are nevertheless unable to detect the presence of the planet in the data and carry out further simulations to show that broader wavelength coverage should enable a planet like HD 75289b to be detected with 99.9 per cent confidence. We investigate the sensitivity of our method and estimate detection tolerances for mismatches between observed and model planetary atmospheres.
Original languageEnglish
Pages (from-to)1097-1107
JournalMonthly Notices of the Royal Astronomical Society
Volume379
Issue number3
DOIs
Publication statusPublished - Aug 2007

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