MAGELLAN ADAPTIVE OPTICS FIRST-LIGHT OBSERVATIONS OF THE EXOPLANET beta PIC b. I. DIRECT IMAGING IN THE FAR-RED OPTICAL WITH MagAO plus VisAO AND IN THE NEAR-IR WITH NICI

Jared R. Males*, Laird M. Close, Katie M. Morzinski, Zahed Wahhaj, Michael C. Liu, Andrew J. Skemer, Derek Kopon, Katherine B. Follette, Alfio Puglisi, Simone Esposito, Armando Riccardi, Enrico Pinna, Marco Xompero, Runa Briguglio, Beth A. Biller, Eric L. Nielsen, Philip M. Hinz, Timothy J. Rodigas, Thomas L. Hayward, Mark ChunChrist Ftaclas, Douglas W. Toomey, Ya-Lin wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present the first ground-based CCD (lambda <1 mu m) image of an extrasolar planet. Using the Magellan Adaptive Optics system's VisAO camera, we detected the extrasolar giant planet beta Pictoris b in Y-short (Y-S, 0.985 mu m), at a separation of 0.470 +/- 0 ''.010 and a contrast of (1.63 +/- 0.49) Chi 10(-5). This detection has a signal-to-noise ratio of 4.1 with an empirically estimated upper limit on false alarm probability of 1.0%. We also present new photometry from the Gemini Near-Infrared Coronagraphic Imager instrument on the Gemini South telescope, in CH4S, 1% (1.58 mu m), K-S (2.18 mu m), and K-cont (2.27 mu m). A thorough analysis of our photometry combined with previous measurements yields an estimated near-IR spectral type of L2.5 +/- 1.5, consistent with previous estimates. We estimate log(L-bol/L-circle dot) = -3.86 +/- 0.04, which is consistent with prior estimates for beta Pic b and with field early-L brown dwarfs (BDs). This yields a hot-start mass estimate of 11.9 +/- 0.7 M-Jup for an age of 21 +/- 4Myr, with an upper limit below the deuterium burning mass. Our L-bol-based hot-start estimate for temperature is T-eff = 1643 +/- 32 K (not including model-dependent uncertainty). Due to the large corresponding model-derived radius of R = 1.43 +/- 0.02 R-Jup, this T-eff is similar to 250 K cooler than would be expected for a field L2.5 BD. Other young, low-gravity (large-radius), ultracool dwarfs and directly imaged EGPs also have lower effective temperatures than are implied by their spectral types. However, such objects tend to be anomalously red in the near-IR compared to field BDs. In contrast, beta Pic b has near-IR colors more typical of an early-L dwarf despite its lower inferred temperature.

Original languageEnglish
Article number32
Number of pages22
JournalAstrophysical Journal
Volume786
Issue number1
DOIs
Publication statusPublished - 1 May 2014

Keywords

  • brown dwarfs
  • instrumentation: adaptive optics
  • planetary systems
  • planets and satellites: detection
  • planets and satellites: individual (beta Pictoris b)
  • stars: individual (beta Pictoris)
  • PLANET-FINDING CAMPAIGN
  • LOW-MASS STARS
  • EXTRASOLAR GIANT PLANETS
  • PICTORIS MOVING GROUP
  • ORION TRAPEZIUM CLUSTER
  • DIRECTLY IMAGED PLANET
  • L DWARF COMPANION
  • ORBITING HR 8799
  • EDGE-ON DISK
  • MID-T DWARFS

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