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Speckle Imaging Characterization of Radial Velocity Exoplanet Systems

Dalba, Paul A. and Kane, Stephen R. and Howell, Steve B. and Horch, Elliott P. and Li, Zhexing and Hirsch, Lea A. and Burt, Jennifer and Brandt, Timothy D. and Močnik, Teo and Henry, Gregory W. and Everett, Mark E. and Rosenthal, Lee J. and Howard, Andrew W. (2021) Speckle Imaging Characterization of Radial Velocity Exoplanet Systems. Astronomical Journal, 161 (3). Art. No. 123. ISSN 0004-6256. doi:10.3847/1538-3881/abd6ed.

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We conducted speckle imaging observations of 53 stellar systems that were members of long-term radial velocity (RV) monitoring campaigns and exhibited substantial accelerations indicative of planetary or stellar companions in wide orbits. Our observations were made with blue and red filters using the Differential Speckle Survey Instrument at Gemini-South and the NN-Explore Exoplanet Stellar Speckle Imager at the WIYN telescope. The speckle imaging identifies eight luminous companions within 2'' of the primary stars. In three of these systems—HD 1388, HD 87359, and HD 104304—the properties of the imaged companion are consistent with the RV measurements, suggesting that these companions may be associated with the primary and the cause of the RV variation. For all 53 stellar systems, we derive differential magnitude limits (i.e., contrast curves) from the imaging. We extend this analysis to include upper limits on companion mass in systems without imaging detections. In 25 systems, we rule out companions with masses greater than 0.2 M⊙, suggesting that the observed RV signals are caused by late-M dwarfs or substellar (potentially planetary) objects. On the other hand, the joint RV and imaging analysis almost entirely rules out planetary explanations of the RV signal for HD 19522 and suggests that the companion must have an angular separation below a few tenths of an arcsecond. This work highlights the importance of combined RV and imaging observations for characterizing the outer regions of nearby planetary systems.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Dalba, Paul A.0000-0002-4297-5506
Kane, Stephen R.0000-0002-7084-0529
Howell, Steve B.0000-0002-2532-2853
Horch, Elliott P.0000-0003-2159-1463
Li, Zhexing0000-0002-4860-7667
Hirsch, Lea A.0000-0001-8058-7443
Burt, Jennifer0000-0002-0040-6815
Brandt, Timothy D.0000-0003-2630-8073
Močnik, Teo0000-0003-4603-556X
Henry, Gregory W.0000-0003-4155-8513
Everett, Mark E.0000-0002-0885-7215
Rosenthal, Lee J.0000-0001-8391-5182
Howard, Andrew W.0000-0001-8638-0320
Additional Information:© 2021 The American Astronomical Society. Received 2020 November 3; revised 2020 December 23; accepted 2020 December 26; published 2021 February 16. The authors thank the anonymous referee for the thoughtful comments that improved the quality and clarity of this work. P.D. acknowledges support from a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1903811. G.W.H. acknowledges long-term support from NASA, NSF, Tennessee State University, and the State of Tennessee through its Centers of Excellence program. A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Based on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the observations in the paper made use of the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI). NESSI was funded by the NASA Exoplanet Exploration Program and the NASA Ames Research Center. NESSI was built at the Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Facilities: Keck:I (HIRES) - , WIYN (NESSI) - , Gemini:South (DSSI) - .
Group:Astronomy Department
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST-1903811
Tennessee State UniversityUNSPECIFIED
State of Tennessee Centers of Excellence programUNSPECIFIED
Subject Keywords:Exoplanets; Radial velocity; Direct imaging; Binary stars
Issue or Number:3
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanets (498); Radial velocity (1332); Direct imaging (387); Binary stars (154)
Record Number:CaltechAUTHORS:20210219-113451409
Persistent URL:
Official Citation:Paul A. Dalba et al 2021 AJ 161 123
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108121
Deposited By: Tony Diaz
Deposited On:19 Feb 2021 20:42
Last Modified:16 Nov 2021 19:09

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