The Astronomical Journal (Jan 2025)
Gaia-4b and 5b: Radial Velocity Confirmation of Gaia Astrometric Orbital Solutions Reveal a Massive Planet and a Brown Dwarf Orbiting Low-mass Stars
- Gudmundur Stefánsson,
- Suvrath Mahadevan,
- Joshua N. Winn,
- Marcus L. Marcussen,
- Shubham Kanodia,
- Simon Albrecht,
- Evan Fitzmaurice,
- Onė Mikulskytė,
- Caleb I. Cañas,
- Juan I. Espinoza-Retamal,
- Yiri Zwart,
- Daniel M. Krolikowski,
- Andrew Hotnisky,
- Paul Robertson,
- Jaime A. Alvarado-Montes,
- Chad F. Bender,
- Cullen H. Blake,
- J. R. Callingham,
- William D. Cochran,
- Megan Delamer,
- Scott A. Diddams,
- Jiayin Dong,
- Rachel B. Fernandes,
- Mark R. Giovinazzi,
- Samuel Halverson,
- Jessica Libby-Roberts,
- Sarah E. Logsdon,
- Michael W. McElwain,
- Joe P. Ninan,
- Jayadev Rajagopal,
- Varghese Reji,
- Arpita Roy,
- Christian Schwab,
- Jason T. Wright
Affiliations
- Gudmundur Stefánsson
- ORCiD
- Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
- Suvrath Mahadevan
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Astrobiology Research Center, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
- Marcus L. Marcussen
- ORCiD
- Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, 8000 Aarhus C, Denmark
- Shubham Kanodia
- ORCiD
- Earth and Planets Laboratory , Carnegie Institution for Science, 5241 Broad Branch Road, NW, WA, DC 20015, USA
- Simon Albrecht
- ORCiD
- Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, 8000 Aarhus C, Denmark
- Evan Fitzmaurice
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Institute for Computational and Data Sciences, The Pennsylvania State University , University Park, PA 16802, USA
- Onė Mikulskytė
- Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
- Caleb I. Cañas
- ORCiD
- NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Juan I. Espinoza-Retamal
- ORCiD
- Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands; Instituto de Astrofísica , Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile; Millennium Institute for Astrophysics , Santiago, Chile
- Yiri Zwart
- ORCiD
- Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
- Daniel M. Krolikowski
- ORCiD
- Steward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721, USA
- Andrew Hotnisky
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Paul Robertson
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, Irvine, CA 92697, USA
- Jaime A. Alvarado-Montes
- ORCiD
- School of Mathematical and Physical Sciences, Macquarie University , Balaclava Road, North Ryde, NSW 2109, Australia; The Macquarie University Astrophysics and Space Technologies Research Centre, Macquarie University , Balaclava Road, North Ryde, NSW 2109, Australia
- Chad F. Bender
- ORCiD
- Steward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721, USA
- Cullen H. Blake
- ORCiD
- Department of Physics and Astronomy, University of Pennsylvania , 209 S 33rd Street, Philadelphia, PA 19104, USA
- J. R. Callingham
- ORCiD
- Leiden Observatory, Leiden University , PO Box 9513, 2300 RA, Leiden, The Netherlands; ASTRON, Netherlands Institute for Radio Astronomy , Oude Hoogeveensedijk 4, Dwingeloo, 7991 PD, The Netherlands
- William D. Cochran
- ORCiD
- McDonald Observatory and Department of Astronomy, The University of Texas at Austin , 2515 Speedway, Austin, TX 78712, USA; Center for Planetary Systems Habitability, The University of Texas at Austin , 2515 Speedway, Austin, TX 78712, USA
- Megan Delamer
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Scott A. Diddams
- ORCiD
- Electrical Computer and Energy Engineering, UCB 425, University of Colorado , Boulder, CO 80309, USA; Department of Physics, 390 UCB, University of Colorado , Boulder, CO 80309, USA
- Jiayin Dong
- ORCiD
- Center for Computational Astrophysics , Flatiron Institute, 162 Fifth Avenue, New York, NY 10010, USA; Department of Astronomy, University of Illinois at Urbana-Champaign , Urbana, IL 61801, USA
- Rachel B. Fernandes
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Mark R. Giovinazzi
- ORCiD
- Department of Physics and Astronomy , Amherst College, Amherst, MA 01002, USA
- Samuel Halverson
- ORCiD
- Jet Propulsion Laboratory , California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Jessica Libby-Roberts
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Sarah E. Logsdon
- ORCiD
- NSF National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Michael W. McElwain
- ORCiD
- Exoplanets and Stellar Astrophysics Laboratory , NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Joe P. Ninan
- ORCiD
- Department of Astronomy and Astrophysics , Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
- Jayadev Rajagopal
- ORCiD
- NSF National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Varghese Reji
- ORCiD
- Department of Astronomy and Astrophysics , Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
- Arpita Roy
- ORCiD
- Astrophysics & Space Institute , Schmidt Sciences, NY 10011, USA
- Christian Schwab
- ORCiD
- School of Mathematical and Physical Sciences, Macquarie University , Balaclava Road, North Ryde, NSW 2109, Australia
- Jason T. Wright
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Penn State Extraterrestrial Intelligence Center, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- DOI
- https://doi.org/10.3847/1538-3881/ada9e1
- Journal volume & issue
-
Vol. 169,
no. 2
p. 107
Abstract
Gaia astrometry of nearby stars is precise enough to detect the tiny displacements induced by substellar companions, but radial velocity (RV) data are needed for definitive confirmation. Here we present RV follow-up observations of 28 M and K stars with candidate astrometric substellar companions, which led to the confirmation of two systems, Gaia-4b and Gaia-5b, identification of five systems that are single lined but require additional data to confirm as substellar companions, and the refutation of 21 systems as stellar binaries. Gaia-4b is a massive planet ( M = 11.8 ± 0.7 M _J ) in a P = 571.3 ± 1.4 day orbit with a projected semimajor axis a _0 = 0.312 ± 0.040 mas orbiting a 0.644 ± 0.02 M _⊙ star. Gaia-5b is a brown dwarf ( M = 20.9 ± 0.5 M _J ) in a P = 358.62 ± 0.20 days eccentric e = 0.6423 ± 0.0026 orbit with a projected angular semimajor axis of a _0 = 0.947 ± 0.038 mas around a 0.34 ± 0.03 M _⊙ star. Gaia-4b is one of the first exoplanets discovered via the astrometric technique, and is one of the most massive planets known to orbit a low-mass star.
Keywords
- Astrometric exoplanet detection
- Exoplanet detection methods
- Astrometry
- Radial velocity
- Exoplanets
- Exoplanet systems
