skip to main content

Title: THE K2-ESPRINT PROJECT. I. DISCOVERY OF THE DISINTEGRATING ROCKY PLANET K2-22b WITH A COMETARY HEAD AND LEADING TAIL

We present the discovery of a transiting exoplanet candidate in the K2 Field-1 with an orbital period of 9.1457 hr: K2-22b. The highly variable transit depths, ranging from ∼0% to 1.3%, are suggestive of a planet that is disintegrating via the emission of dusty effluents. We characterize the host star as an M-dwarf with T{sub eff} ≃ 3800 K. We have obtained ground-based transit measurements with several 1-m class telescopes and with the GTC. These observations (1) improve the transit ephemeris; (2) confirm the variable nature of the transit depths; (3) indicate variations in the transit shapes; and (4) demonstrate clearly that at least on one occasion the transit depths were significantly wavelength dependent. The latter three effects tend to indicate extinction of starlight by dust rather than by any combination of solid bodies. The K2 observations yield a folded light curve with lower time resolution but with substantially better statistical precision compared with the ground-based observations. We detect a significant “bump” just after the transit egress, and a less significant bump just prior to transit ingress. We interpret these bumps in the context of a planet that is not only likely streaming a dust tail behind it, but alsomore » has a more prominent leading dust trail that precedes it. This effect is modeled in terms of dust grains that can escape to beyond the planet's Hill sphere and effectively undergo “Roche lobe overflow,” even though the planet's surface is likely underfilling its Roche lobe by a factor of 2.« less
Authors:
 [1] ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] ;
  1. Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
  2. Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
  3. Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain)
  4. Institut d’Astrophysique et Géophysique, Université de Liège, allée du 6 Août 17, B-4000 Liège (Belgium)
  5. Visidyne, Inc., 111 South Bedford St., Suite 103, Burlington, MA 01803 (United States)
  6. Dipartimento di Fisica, Universitá di Torino, via P. Giuria 1, I-10125, Torino (Italy)
  7. Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan)
  8. Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, Facultat de Ciències, Torre C5, parell, 2a pl., E-08193 Bellaterra (Spain)
  9. Vanderbilt University, Nashville, TN 37235 (United States)
  10. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)
  11. Department of Geology and Geophysics, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822 (United States)
  12. Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38206 La Laguna, Tenerife (Spain)
  13. Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
Publication Date:
OSTI Identifier:
22518776
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 812; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; COMPARATIVE EVALUATIONS; COSMIC DUST; DETECTION; DIAGRAMS; EMISSION; PLANETS; ROCHE EQUIPOTENTIALS; SATELLITE ATMOSPHERES; SATELLITES; STARS; TELESCOPES; TIME RESOLUTION; VISIBLE RADIATION