CHARACTERIZING the ATMOSPHERES of the HR8799 PLANETS with HST/WFC3

Abhijith Rajan, Travis S Barman, Rémi Soummer, J. Brendan Hagan, Jennifer Patience, Laurent Pueyo, Élodie Choquet, Quinn Konopacky, Bruce Macintosh, Christian Marois

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We present results from a Hubble Space Telescope (HST) program characterizing the atmospheres of the outer two planets in the HR8799 system. The images were taken over 15 orbits in three near-infrared (near-IR) medium-band filters - F098M, F127M, and F139M - using the Wide Field Camera 3. One of the three filters is sensitive to a water absorption band inaccessible from ground-based observations, providing a unique probe of the thermal emission from the atmospheres of these young giant planets. The observations were taken at 30 different spacecraft rolls to enable angular differential imaging (ADI), and the full data set was analyzed with the Karhunen-Loéve Image Projection routine, an advanced image processing algorithm adapted to work with HST data. To achieve the required high contrast at subarcsecond resolution, we utilized the pointing accuracy of HST in combination with an improved pipeline designed to combine the dithered ADI data with an algorithm designed to both improve the image resolution and accurately measure the photometry. The results include F127M (J) detections of the outer planets, HR8799b and c, and the first detection of HR8799b in the water-band (F139M) filter. The F127M photometry for HR8799c agrees well with fitted atmospheric models, resolving the longstanding difficulty in consistently modeling the near-IR flux of the planet.

Original languageEnglish (US)
Article numberL33
JournalAstrophysical Journal Letters
Volume809
Issue number2
DOIs
StatePublished - Aug 20 2015

Keywords

  • brown dwarfs
  • planetary systems
  • stars: atmospheres
  • stars: low-mass

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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    Rajan, A., Barman, T. S., Soummer, R., Hagan, J. B., Patience, J., Pueyo, L., Choquet, É., Konopacky, Q., Macintosh, B., & Marois, C. (2015). CHARACTERIZING the ATMOSPHERES of the HR8799 PLANETS with HST/WFC3. Astrophysical Journal Letters, 809(2), [L33]. https://doi.org/10.1088/2041-8205/809/2/L33