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Title: HD 106906 b: A PLANETARY-MASS COMPANION OUTSIDE A MASSIVE DEBRIS DISK

We report the discovery of a planetary-mass companion, HD 106906 b, with the new Magellan Adaptive Optics (MagAO) + Clio2 system. The companion is detected with Clio2 in three bands: J, K{sub S} , and L', and lies at a projected separation of 7.''1 (650 AU). It is confirmed to be comoving with its 13 ± 2 Myr F5 host using Hubble Space Telescope Advanced Camera for Surveys astrometry over a time baseline of 8.3 yr. DUSTY and COND evolutionary models predict that the companion's luminosity corresponds to a mass of 11 ± 2 M {sub Jup}, making it one of the most widely separated planetary-mass companions known. We classify its Magellan/Folded-Port InfraRed Echellette J/H/K spectrum as L2.5 ± 1; the triangular H-band morphology suggests an intermediate surface gravity. HD 106906 A, a pre-main-sequence Lower Centaurus Crux member, was initially targeted because it hosts a massive debris disk detected via infrared excess emission in unresolved Spitzer imaging and spectroscopy. The disk emission is best fit by a single component at 95 K, corresponding to an inner edge of 15-20 AU and an outer edge of up to 120 AU. If the companion is on an eccentric (e > 0.65) orbit, it couldmore » be interacting with the outer edge of the disk. Close-in, planet-like formation followed by scattering to the current location would likely disrupt the disk and is disfavored. Furthermore, we find no additional companions, though we could detect similar-mass objects at projected separations >35 AU. In situ formation in a binary-star-like process is more probable, although the companion-to-primary mass ratio, at <1%, is unusually small.« less
Authors:
; ; ; ; ; ; ; ; ;  [1] ; ;  [2] ;  [3] ; ; ;  [4] ;  [5]
  1. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  2. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  3. Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States)
  4. Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy)
  5. Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Road NW, Washington, DC 20015 (United States)
Publication Date:
OSTI Identifier:
22364071
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BINARY STARS; CAMERAS; EMISSION; EMISSION SPECTROSCOPY; GRAVITATION; LUMINOSITY; MAIN SEQUENCE STARS; MASS; MORPHOLOGY; OPTICS; ORBITS; PLANETS; SPACE; SURFACES; TELESCOPES