IMAGES OF THE EXTENDED OUTER REGIONS OF THE DEBRIS RING AROUND HR 4796 A

Journal Article · Sat Dec 10 00:00:00 EST 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/743/1/L6· OSTI ID:22047311

Thalmann, C; Dominik, C ^[1]; Janson, M ^[2]; Buenzli, E ^[3]; Brandt, T D ^[4]; Wisniewski, J P ^[5]; Moro-Martin, A ^[6]; Usuda, T; Egner, S; Golota, T; Guyon, O ^[7]; Schneider, G ^[8]; Carson, J ^[9]; McElwain, M W; Grady, C A ^[10]; Goto, M; Brandner, W; Feldt, M ^[11]; Abe, L ^[12]; Fukue, T ^[13] ; others, and

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1. Anton Pannekoek Astronomical Institute, University of Amsterdam, Amsterdam (Netherlands)
2. Department of Astronomy and Astrophysics, University of Toronto, Toronto (Canada)
3. Institute for Astronomy, ETH Zurich, Zurich (Switzerland)
4. Department of Astrophysical Sciences, Princeton University, Princeton, NJ (United States)
5. Department of Astronomy, University of Washington, Seattle, WA (United States)
6. Department of Astrophysics, CAB-CSIC/INTA, Madrid (Spain)
7. Subaru Telescope, Hilo, HI (United States)
8. Steward Observatory, The University of Arizona, Tucson, AZ (United States)
9. College of Charleston, Charleston, SC (United States)
10. Goddard Space Flight Center, Greenbelt, MD (United States)
11. Max Planck Institute for Astronomy, Heidelberg (Germany)
12. Laboratoire Hippolyte Fizeau, Nice (France)
13. National Astronomical Observatory of Japan, Tokyo (Japan)

We present high-contrast images of HR 4796 A taken with Subaru/HiCIAO in the H band, resolving the debris disk in scattered light. The application of specialized angular differential imaging methods allows us to trace the inner edge of the disk with high precision and reveals a pair of 'streamers' extending radially outward from the ansae. Using a simple disk model with a power-law surface brightness profile, we demonstrate that the observed streamers can be understood as part of the smoothly tapered outer boundary of the debris disk, which is most visible at the ansae. Our observations are consistent with the expected result of a narrow planetesimal ring being ground up in a collisional cascade, yielding dust with a wide range of grain sizes. Radiation forces leave large grains in the ring and push smaller grains onto elliptical or even hyperbolic trajectories. We measure and characterize the disk's surface brightness profile, and confirm the previously suspected offset of the disk's center from the star's position along the ring's major axis. Furthermore, we present first evidence for an offset along the minor axis. Such offsets are commonly viewed as signposts for the presence of unseen planets within a disk's cavity. Our images also offer new constraints on the presence of companions down to the planetary mass regime ({approx}9 M{sub Jup} at 0.''5, {approx}3 M{sub Jup} at 1'').

• OSTI ID: 22047311
• Journal Information: Astrophysical Journal Letters, Vol. 743, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCURACY
ASTROPHYSICS
BRIGHTNESS
COSMIC DUST
GRAIN SIZE
IMAGES
MASS
PLANETS
RESOLUTION
STARS
SURFACES
TRAJECTORIES
VISIBLE RADIATION