CaltechAUTHORS
Published December 1, 2020 | Version Published + Accepted Version
Journal Article Open

SCExAO/CHARIS Direct Imaging Discovery of a 20 au Separation, Low-mass Ratio Brown Dwarf Companion to an Accelerating Sun-like Star

Creators

  • 1. ROR icon University of Hawaii at Hilo
  • 2. ROR icon Ames Research Center
  • 3. ROR icon Eureka Scientific
  • 4. ROR icon University of California, Santa Barbara
  • 5. ROR icon Astrobiology Center
  • 6. ROR icon National Astronomical Observatory of Japan
  • 7. ROR icon University of Notre Dame
  • 8. ROR icon University of Arizona
  • 9. ROR icon National Research Council Canada
  • 10. ROR icon University of Victoria
  • 11. ROR icon Goddard Space Flight Center
  • 12. ROR icon California Institute of Technology
  • 13. ROR icon Observatoire de la Côte d'Azur
  • 14. ROR icon Lagrange Laboratory
  • 15. ROR icon University of Edinburgh
  • 16. ROR icon Georgia Institute of Technology
  • 17. ROR icon European Space Research and Technology Centre
  • 18. ROR icon Stockholm University
  • 19. ROR icon Princeton University
  • 20. ROR icon Institute of Space and Astronautical Science
  • 21. ROR icon University of Oklahoma
  • 22. ROR icon Infrared Processing and Analysis Center
  • 23. ROR icon University of Tokyo

Abstract

We present the direct imaging discovery of a substellar companion to the nearby Sun-like star, HD 33632 Aa, at a projected separation of ~20 au, obtained with SCExAO/CHARIS integral field spectroscopy complemented by Keck/NIRC2 thermal infrared imaging. The companion, HD 33632 Ab, induces a 10.5σ astrometric acceleration on the star as detected with the Gaia and Hipparcos satellites. SCExAO/CHARIS JHK (1.1–2.4 μm) spectra and Keck/NIRC2 L_p (3.78 μm) photometry are best matched by a field L/T transition object: an older, higher-gravity, and less dusty counterpart to HR 8799 cde. Combining our astrometry with Gaia/Hipparcos data and archival Lick Observatory radial velocities, we measure a dynamical mass of 46.4 ± 8 M_J and an eccentricity of e < 0.46 at 95% confidence. HD 33632 Ab's mass and mass ratio (4.0% ± 0.7%) are comparable to the low-mass brown dwarf GJ 758 B and intermediate between the more massive brown dwarf HD 19467 B and the (near-)planet-mass companions to HR 2562 and GJ 504. Using Gaia to select for direct imaging observations with the newest extreme adaptive optics systems can reveal substellar or even planet-mass companions on solar system–like scales at an increased frequency compared to blind surveys.

Additional Information

© 2020. The American Astronomical Society. Received 2020 September 19; revised 2020 October 21; accepted 2020 October 30; published 2020 November 30. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. We thank Eric Mamajek and William Cochran for helpful comments regarding the HD 33632 system properties. The authors acknowledge the very significant cultural role and reverence that the summit of Maunakea holds within the Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We acknowledge the critical importance of the current and recent Subaru and Keck Observatory daycrew, technicians, support astronomers, telescope operators, computer support, and office staff employees, especially during the challenging times presented by the COVID-19 pandemic. Their expertise, ingenuity, and dedication is indispensable to the continued successful operation of these observatories. We thank the Subaru and NASA Keck Time Allocation Committees for their generous support of this program. T.C. was supported by a NASA Senior Postdoctoral Fellowship and NASA/Keck grant LK-2663-948181. T.B. gratefully acknowledges support from the Heising-Simons foundation and from NASA under grant #80NSSC18K0439. M.T. is supported by JSPS KAKENHI grant #18H05442. The development of SCExAO was supported by JSPS (Grant-in-Aid for Research #23340051, #26220704, and #23103002), Astrobiology Center of NINS, Japan, the Mt Cuba Foundation, and the director's contingency fund at Subaru Telescope. CHARIS was developed under the support by the Grant-in-Aid for Scientific Research on Innovative Areas #2302. Some of 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.

Attached Files

Published - Currie_2020_ApJL_904_L25.pdf

Accepted Version - 2011.08855.pdf

Files

2011.08855.pdf

Files (4.0 MB)

Name Size
md5:f12fd786bc89481974bf78671db8559b
2.1 MB Preview Download
md5:a6bff7d9ab39c3e2a89c6674b396b2b3
2.0 MB Preview Download

Additional details

Identifiers

Eprint ID
106912
Resolver ID
CaltechAUTHORS:20201204-110356649

Related works

Describes
https://arxiv.org/abs/2011.08855 (URL)

Funding

NASA Postdoctoral Program
NASA
LK-2663-948181
NASA
80NSSC18K0439
Japan Society for the Promotion of Science (JSPS)
18H05442
NASA Hubble Fellowship
NASA Sagan Fellowship
Japan Society for the Promotion of Science (JSPS)
23340051
Japan Society for the Promotion of Science (JSPS)
26220704
Japan Society for the Promotion of Science (JSPS)
23103002
National Institutes of Natural Sciences of Japan
Mt. Cuba Astronomical Foundation
Subaru Telescope
Japan Society for the Promotion of Science (JSPS)
2302
W. M. Keck Foundation
Heising-Simons Foundation

Dates

Created
2020-12-05
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)