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Journal Articles The Astronomical Journal Year : 2016

The Orbit and Transit Prospects for β Pictoris b Constrained with One Milliarcsecond Astrometry

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Jason J. Wang
  • Function : Author
James R. Graham
  • Function : Author
Laurent Pueyo
  • Function : Author
Paul Kalas
Maxwell A. Millar-Blanchaer
  • Function : Author
Jean-Baptiste Ruffio
  • Function : Author
Robert J. de Rosa
  • Function : Author
S. Mark Ammons
  • Function : Author
Pauline Arriaga
Vanessa P. Bailey
  • Function : Author
Travis S. Barman
  • Function : Author
Joanna Bulger
  • Function : Author
Adam S. Burrows
  • Function : Author
Andrew Cardwell
  • Function : Author
Christine H. Chen
  • Function : Author
Jeffrey K. Chilcote
  • Function : Author
Tara Cotten
  • Function : Author
Michael P. Fitzgerald
  • Function : Author
Katherine B. Follette
  • Function : Author
René Doyon
Alexandra Z. Greenbaum
  • Function : Author
Pascale Hibon
  • Function : Author
Li-Wei Hung
  • Function : Author
Patrick Ingraham
  • Function : Author
Quinn M. Konopacky
  • Function : Author
James E. Larkin
  • Function : Author
Bruce Macintosh
Jérôme Maire
  • Function : Author
Franck Marchis
Mark S. Marley
  • Function : Author
Christian Marois
Stanimir Metchev
  • Function : Author
Eric L. Nielsen
  • Function : Author
Rebecca Oppenheimer
  • Function : Author
David W. Palmer
  • Function : Author
Rahul Patel
  • Function : Author
Jenny Patience
  • Function : Author
Marshall D. Perrin
Lisa A. Poyneer
  • Function : Author
Abhijith Rajan
  • Function : Author
Julien Rameau
  • Function : Author
Fredrik T. Rantakyrö
  • Function : Author
Dmitry Savransky
  • Function : Author
Anand Sivaramakrishnan
  • Function : Author
Inseok Song
  • Function : Author
Remi Soummer
  • Function : Author
Sandrine Thomas
  • Function : Author
Gautam Vasisht
  • Function : Author
David Vega
  • Function : Author
J. Kent Wallace
  • Function : Author
Kimberly Ward-Duong
  • Function : Author
Sloane J. Wiktorowicz
  • Function : Author
Schuyler G. Wolff
  • Function : Author

Abstract

A principal scientific goal of the Gemini Planet Imager (GPI) is obtaining milliarcsecond astrometry to constrain exoplanet orbits. However, astrometry of directly imaged exoplanets is subject to biases, systematic errors, and speckle noise. Here, we describe an analytical procedure to forward model the signal of an exoplanet that accounts for both the observing strategy (angular and spectral differential imaging) and the data reduction method (Karhunen-Loève Image Projection algorithm). We use this forward model to measure the position of an exoplanet in a Bayesian framework employing Gaussian processes and Markov-chain Monte Carlo to account for correlated noise. In the case of GPI data on β Pic b, this technique, which we call Bayesian KLIP-FM Astrometry (BKA), outperforms previous techniques and yields 1σ errors at or below the one milliarcsecond level. We validate BKA by fitting a Keplerian orbit to 12 GPI observations along with previous astrometry from other instruments. The statistical properties of the residuals confirm that BKA is accurate and correctly estimates astrometric errors. Our constraints on the orbit of β Pic b firmly rule out the possibility of a transit of the planet at 10-σ significance. However, we confirm that the Hill sphere of β Pic b will transit, giving us a rare chance to probe the circumplanetary environment of a young, evolving exoplanet. We provide an ephemeris for photometric monitoring of the Hill sphere transit event, which will begin at the start of April in 2017 and finish at the end of January in 2018.

Dates and versions

insu-03691493 , version 1 (09-06-2022)

Identifiers

Cite

Jason J. Wang, James R. Graham, Laurent Pueyo, Paul Kalas, Maxwell A. Millar-Blanchaer, et al.. The Orbit and Transit Prospects for β Pictoris b Constrained with One Milliarcsecond Astrometry. The Astronomical Journal, 2016, 152, ⟨10.3847/0004-6256/152/4/97⟩. ⟨insu-03691493⟩
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