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dc.contributor.authorWang, Jason J.
dc.contributor.authorGraham, James R.
dc.contributor.authorPueyo, Laurent
dc.contributor.authorKalas, Paul
dc.contributor.authorMillar-Blanchaer, Maxwell A.
dc.contributor.authorRuffio, Jean-Baptiste
dc.contributor.authorDe Rosa, Robert J.
dc.contributor.authorAmmons, S. Mark
dc.contributor.authorArriaga, Pauline
dc.contributor.authorBailey, Vanessa P.
dc.contributor.authorBarman, Travis S.
dc.contributor.authorBulger, Joanna
dc.contributor.authorBurrows, Adam
dc.contributor.authorCardwell, Andrew
dc.contributor.authorChen, Christine H.
dc.contributor.authorChilcote, Jeffrey
dc.contributor.authorCotten, Tara
dc.contributor.authorFitzgerald, Michael P.
dc.contributor.authorFollette, Katherine B.
dc.contributor.authorDoyon, René
dc.contributor.authorDuchêne, Gaspard
dc.contributor.authorGreenbaum, Alexandra Z.
dc.contributor.authorHibon, Pascale
dc.contributor.authorHung, Li-Wei
dc.contributor.authorIngraham, Patrick
dc.contributor.authorKonopacky, Quinn
dc.contributor.authorLarkin, James E.
dc.contributor.authorMacintosh, Bruce
dc.contributor.authorMaire, Jérôme
dc.contributor.authorMarchis, Franck
dc.contributor.authorMarley, Mark S.
dc.contributor.authorMarois, Christian
dc.contributor.authorMetchev, Stanimir A.
dc.contributor.authorNielsen, Eric L.
dc.contributor.authorOppenheimer, Rebecca
dc.contributor.authorPalmer, David W.
dc.contributor.authorPatel, Rahul I.
dc.contributor.authorPatience, Jenny
dc.contributor.authorPerrin, Marshall
dc.contributor.authorPoyneer, Lisa A.
dc.contributor.authorRajan, Abhijith
dc.contributor.authorRameau, Julien
dc.contributor.authorRantakyrö, Fredrik T.
dc.contributor.authorSavransky, Dmitry
dc.contributor.authorSivaramakrishnan, Anand
dc.contributor.authorSong, Inseok
dc.contributor.authorSoummer, Remi
dc.contributor.authorThomas, Sandrine
dc.contributor.authorVasisht, Gautam
dc.contributor.authorVega, David
dc.contributor.authorWallace, J. Kent
dc.contributor.authorWard-Duong, Kimberly
dc.contributor.authorWiktorowicz, Sloane
dc.contributor.authorWolff, Schuyler
dc.date.accessioned2017-07-17T16:46:57Z
dc.date.available2017-07-17T16:46:57Z
dc.date.issued2016-10-03
dc.identifier.citationTHE ORBIT AND TRANSIT PROSPECTS FOR β PICTORIS b CONSTRAINED WITH ONE MILLIARCSECOND ASTROMETRY 2016, 152 (4):97 The Astronomical Journalen
dc.identifier.issn1538-3881
dc.identifier.doi10.3847/0004-6256/152/4/97
dc.identifier.urihttp://hdl.handle.net/10150/624735
dc.description.abstractA 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-Loeve 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 beta Pic b, this technique, which we call Bayesian KLIP-FM Astrometry (BKA), outperforms previous techniques and yields 1 sigma 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 beta Pic b firmly rule out the possibility of a transit of the planet at 10-sigma significance. However, we confirm that the Hill sphere of beta 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.
dc.description.sponsorshipGemini Observatory; National Science Foundation [NSF AST-1518332]; NASA [NNX15AC89G, NNX15AD95G]; U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]en
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/1538-3881/152/i=4/a=97?key=crossref.43f4f9761b39650337dce49f68ff54aeen
dc.rights© 2016. The American Astronomical Society. All rights reserved.en
dc.subjectastrometryen
dc.subjectplanets and satellites: individual (beta Pictoris b)en
dc.subjecttechniques: image processingen
dc.titleTHE ORBIT AND TRANSIT PROSPECTS FOR β PICTORIS b CONSTRAINED WITH ONE MILLIARCSECOND ASTROMETRYen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Lunar & Planetary Laben
dc.identifier.journalThe Astronomical Journalen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-08-13T21:00:56Z
html.description.abstractA 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-Loeve 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 beta Pic b, this technique, which we call Bayesian KLIP-FM Astrometry (BKA), outperforms previous techniques and yields 1 sigma 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 beta Pic b firmly rule out the possibility of a transit of the planet at 10-sigma significance. However, we confirm that the Hill sphere of beta 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.


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