The HR 4796A Debris System: Discovery of Extensive Exo-ring Dust Material

Glenn Schneider, John H. Debes, Carol A. Grady, Andras Gáspár, Thomas Henning, Dean C. Hines, Marc J. Kuchner, Marshall Perrin, John P. Wisniewski

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The optically and IR-bright and starlight-scattering HR 4796A ringlike debris disk is one of the most- (and best-) studied exoplanetary debris systems. The presence of a yet-undetected planet has been inferred (or suggested) from the narrow width and inner/outer truncation radii of its r = 1.″05 (77 au) debris ring. We present new, highly sensitive Hubble Space Telescope (HST) visible-light images of the HR 4796A circumstellar debris system and its environment over a very wide range of stellocentric angles from 0.″32 (23 au) to ≈15″ (1100 au). These very high-contrast images were obtained with the Space Telescope Imaging Spectrograph (STIS) using six-roll PSF template-subtracted coronagraphy suppressing the primary light of HR 4796A, with three image-plane occulters, and simultaneously subtracting the background light from its close angular proximity M2.5V companion. The resulting images unambiguously reveal the debris ring embedded within a much larger, morphologically complex, and biaxially asymmetric exo-ring scattering structure. These images at visible wavelengths are sensitive to and map the spatial distribution, brightness, and radial surface density of micron-size particles over 5 dex in surface brightness. These particles in the exo-ring environment may be unbound from the system and interacting with the local ISM. Herein, we present a new morphological and photometric view of the larger-than-prior-seen HR 4796A exoplanetary debris system with sensitivity to small particles at stellocentric distances an order of magnitude greater than has previously been observed.

Original languageEnglish (US)
Article number77
JournalAstronomical Journal
Volume155
Issue number2
DOIs
StatePublished - Feb 2018
Externally publishedYes

Keywords

  • ISM: general
  • methods: observational
  • stars: individual: HR 4796A

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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