Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS

Details Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS

2009-07-29

arxiv.org/abs/0907.4991v1

Astronomy and Astrophysics

Astrophysics

Earth and Planetary Astrophysics

9 pages, 7 figures. Accepted for publication in A&A

Scientific paper

We present Hubble Space Telescope near-infrared transit photometry of the nearby hot-Jupiter HD189733b. The observations were taken with the NICMOS instrument during five transits, with three transits executed with a narrowband filter at 1.87 microns and two performed with a narrowband filter at 1.66 microns. Our observing strategy using narrowband filters is insensitive to the usual HST intra-orbit and orbit-to-orbit measurement of systematic errors, allowing us to accurately and robustly measure the near-IR wavelength dependance of the planetary radius. Our measurements fail to reproduce the Swain et al. absorption signature of atmospheric water below 2 microns at a 5-sigma confidence level. We measure a planet-to-star radius contrast of 0.15498+/-0.00035 at 1.66 microns and a contrast of 0.15517+/-0.00019 at 1.87 microns. Both of our near-IR planetary radii values are in excellent agreement with the levels expected from Rayleigh scattering by sub-micron haze particles, observed at optical wavelengths, indicating that upper-atmospheric haze still dominates the near-IR transmission spectra over the absorption from gaseous molecular species at least below 2 microns.

Affiliated with

Also associated with

No associations

Rating

Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-520882