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

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

关键词: ASYMMETRY;    BACKGROUND RADIATION;    BRIGHTNESS DISTRIBUTION;    CORONAGRAPHS;    DEBRIS;    HUBBLE SPACE TELESCOPE;    IMAGING TECHNIQUES;    MICROPARTICLES;    NEAR INFRARED RADIATION;    SCATTERING;    SPECTROGRAPHS;    STELLAR ENVELOPES;   

RP-ID  :  GSFC-E-DAA-TN64835

学科分类：天体物理学

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

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 = 1farcs05 (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 0farcs32 (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.