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Deep Orbital Search for Additional Planets in the HR 8799 System

Thompson, William and Marois, Christian and Do Ó, Clarissa R. and Konopacky, Quinn and Ruffio, Jean-Baptiste and Wang, Jason and Skemer, Andy J. and de Rosa, Robert J. and Macintosh, Bruce (2023) Deep Orbital Search for Additional Planets in the HR 8799 System. Astronomical Journal, 165 (1). Art. No. 29. ISSN 0004-6256. doi:10.3847/1538-3881/aca1af.

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The HR 8799 system hosts four massive planets orbiting 15 and 80 au. Studies of the system's orbital stability and its outer debris disk open the possibility of additional planets, both interior to and exterior to the known system. Reaching a sufficient sensitivity to search for interior planets is very challenging due to the combination of bright quasi-static speckle noise close to the stellar diffraction core and relatively fast orbital motion. In this work, we present a deep L-band imaging campaign using NIRC2 at Keck comprising 14 observing sequences. We further re-reduce archival data for a total of 16.75 hr, one of the largest uniform data sets of a single direct imaging target. Using a Bayesian modeling technique for detecting planets in images while compensating for plausible orbital motion, we then present deep limits on the existence of additional planets in the HR 8799 system. The final combination shows a tentative candidate, consistent with 4–7 M_jup at 4–5 au, detected with an equivalent false-alarm probability better than 3σ. This analysis technique is widely applicable to archival data and to new observations from upcoming missions that revisit targets at multiple epochs.

Item Type:Article
Related URLs:
URLURL TypeDescription
Thompson, William0000-0001-5684-4593
Marois, Christian0000-0002-4164-4182
Do Ó, Clarissa R.0000-0001-5173-2947
Konopacky, Quinn0000-0002-9936-6285
Ruffio, Jean-Baptiste0000-0003-2233-4821
Wang, Jason0000-0003-0774-6502
Skemer, Andy J.0000-0001-6098-3924
de Rosa, Robert J.0000-0002-4918-0247
Macintosh, Bruce0000-0003-1212-7538
Additional Information:The authors thank Dori Blakely, Thayne Curry, and the anonymous referee for providing feedback that greatly improved this work. W.T. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), 466479467. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agency. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. This work has made use of data from the European Space Agency (ESA) mission Gaia ( Gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)466479467
National Research Council of CanadaUNSPECIFIED
Canadian Space Agency (CSA)UNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20230117-370770100.25
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118830
Deposited By: Research Services Depository
Deposited On:10 Feb 2023 20:51
Last Modified:10 Feb 2023 20:51

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