The Astronomical Journal (Jan 2023)
A Mini-Neptune Orbiting the Metal-poor K Dwarf BD+29 2654
- Fei Dai,
- Kevin C. Schlaufman,
- Henrique Reggiani,
- Luke Bouma,
- Andrew W. Howard,
- Ashley Chontos,
- Daria Pidhorodetska,
- Judah Van Zandt,
- Joseph M. Akana Murphy,
- Ryan A. Rubenzahl,
- Alex S. Polanski,
- Jack Lubin,
- Corey Beard,
- Steven Giacalone,
- Rae Holcomb,
- Natalie M. Batalha,
- Ian Crossfield,
- Courtney Dressing,
- Benjamin Fulton,
- Daniel Huber,
- Howard Isaacson,
- Stephen R. Kane,
- Erik A. Petigura,
- Paul Robertson,
- Lauren M. Weiss,
- Alexander A. Belinski,
- Andrew W. Boyle,
- Christopher J. Burke,
- Amadeo Castro-González,
- David R. Ciardi,
- Tansu Daylan,
- Akihiko Fukui,
- Holden Gill,
- Natalia M. Guerrero,
- Coel Hellier,
- Steve B. Howell,
- Jorge Lillo-Box,
- Felipe Murgas,
- Norio Narita,
- Enric Pallé,
- David R. Rodriguez,
- Arjun B. Savel,
- Avi Shporer,
- Keivan G. Stassun,
- Stephanie Striegel,
- Douglas A. Caldwell,
- Jon M. Jenkins,
- George R. Ricker,
- Sara Seager,
- Roland Vanderspek,
- Joshua N. Winn
Affiliations
- Fei Dai
- ORCiD
- Division of Geological and Planetary Sciences , 1200 E California Boulevard, Pasadena, CA 91125, USA ; [email protected]; Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Kevin C. Schlaufman
- ORCiD
- William H. Miller III Department of Physics and Astronomy, Johns Hopkins University , 3400 N Charles Street, Baltimore, MD 21218, USA
- Henrique Reggiani
- ORCiD
- The Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USA
- Luke Bouma
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Andrew W. Howard
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Ashley Chontos
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA; Institute for Astronomy, University of Hawai‘i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- Daria Pidhorodetska
- ORCiD
- Department of Earth and Planetary Sciences, University of California , Riverside, CA 92521, USA
- Judah Van Zandt
- ORCiD
- Department of Physics & Astronomy, University of California Los Angeles , Los Angeles, CA 90095, USA
- Joseph M. Akana Murphy
- ORCiD
- Department of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Ryan A. Rubenzahl
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Alex S. Polanski
- ORCiD
- Department of Physics and Astronomy, University of Kansas , Lawrence, KS 66045, USA
- Jack Lubin
- ORCiD
- Department of Physics & Astronomy, University of California Irvine , Irvine, CA 92697, USA
- Corey Beard
- ORCiD
- Department of Physics & Astronomy, University of California Irvine , Irvine, CA 92697, USA
- Steven Giacalone
- ORCiD
- Department of Astronomy, University of California Berkeley , Berkeley, CA 94720, USA
- Rae Holcomb
- ORCiD
- Department of Physics & Astronomy, University of California Irvine , Irvine, CA 92697, USA
- Natalie M. Batalha
- ORCiD
- Department of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95060, USA
- Ian Crossfield
- Department of Physics and Astronomy, University of Kansas , Lawrence, KS 66045, USA
- Courtney Dressing
- ORCiD
- 501 Campbell Hall, University of California at Berkeley , Berkeley, CA 94720, USA
- Benjamin Fulton
- ORCiD
- NASA Exoplanet Science Institute/Caltech-IPAC , MC 314-6, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Daniel Huber
- ORCiD
- Institute for Astronomy, University of Hawai‘i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA; Sydney Institute for Astronomy, School of Physics, University of Sydney NSW 2006 , Australia
- Howard Isaacson
- ORCiD
- 501 Campbell Hall, University of California at Berkeley , Berkeley, CA 94720, USA; Centre for Astrophysics, University of Southern Queensland , Toowoomba, QLD 4350, Australia
- Stephen R. Kane
- ORCiD
- Department of Earth and Planetary Sciences, University of California , Riverside, CA 92521, USA
- Erik A. Petigura
- ORCiD
- Department of Physics & Astronomy, University of California Los Angeles , Los Angeles, CA 90095, USA
- Paul Robertson
- ORCiD
- Department of Physics & Astronomy, University of California Irvine , Irvine, CA 92697, USA
- Lauren M. Weiss
- ORCiD
- Department of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA
- Alexander A. Belinski
- ORCiD
- Sternberg Astronomical Institute Lomonosov Moscow State University , Universitetskii prospekt, 119992, Moscow, Russia
- Andrew W. Boyle
- ORCiD
- Department of Astronomy, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- Christopher J. Burke
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Amadeo Castro-González
- ORCiD
- Centro de Astrobiología (CAB, CSIC-INTA), Depto. de Astrofísica, ESAC campus, E-28692, Villanueva de la Cañada (Madrid), Spain
- David R. Ciardi
- ORCiD
- Caltech/IPAC-NASA Exoplanet Science Institute , 770 S. Wilson Avenue, Pasadena, CA 91106, USA
- Tansu Daylan
- ORCiD
- Department of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USA
- Akihiko Fukui
- ORCiD
- Komaba Institute for Science, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain
- Holden Gill
- ORCiD
- Department of Astronomy, University of California Berkeley , Berkeley, CA 94720, USA
- Natalia M. Guerrero
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Astronomy, University of Florida , Gainesville, FL 32611, USA
- Coel Hellier
- ORCiD
- Astrophysics Group, Keele University , Staffordshire, ST5 5BG, UK
- Steve B. Howell
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Jorge Lillo-Box
- ORCiD
- Centro de Astrobiología (CAB, CSIC-INTA), Depto. de Astrofísica, ESAC campus, E-28692, Villanueva de la Cañada (Madrid), Spain
- Felipe Murgas
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206 La Laguna, Tenerife, Spain
- Norio Narita
- ORCiD
- Komaba Institute for Science, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain; Astrobiology Center , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Enric Pallé
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain
- David R. Rodriguez
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Arjun B. Savel
- ORCiD
- Department of Astronomy, University of Maryland , College Park, MD 20742, USA
- Avi Shporer
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Keivan G. Stassun
- ORCiD
- Department of Physics and Astronomy, Vanderbilt University , Nashville, TN 37235, USA
- Stephanie Striegel
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA; SETI Institute , 339 N Bernardo Ave Suite 200, Mountain View, CA 94043, USA
- Douglas A. Caldwell
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Jon M. Jenkins
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- George R. Ricker
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Sara Seager
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Aeronautics and Astronautics, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Roland Vanderspek
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USA
- DOI
- https://doi.org/10.3847/1538-3881/acdee8
- Journal volume & issue
-
Vol. 166,
no. 2
p. 49
Abstract
We report the discovery and Doppler mass measurement of a 7.4 days 2.3 R _⊕ mini-Neptune around a metal-poor K dwarf BD+29 2654 (TOI-2018). Based on a high-resolution Keck/HIRES spectrum, the Gaia parallax, and multiwavelength photometry from the UV to the mid-infrared, we found that the host star has ${T}_{\mathrm{eff}}={4174}_{-42}^{+34}$ K, $\mathrm{log}g={4.62}_{-0.03}^{+0.02}$ , [Fe/H] = − 0.58 ± 0.18, M _* = 0.57 ± 0.02 M _⊙ , and R _* = 0.62 ± 0.01 R _⊙ . Precise Doppler measurements with Keck/HIRES revealed a planetary mass of M _p = 9.2 ± 2.1 M _⊕ for TOI-2018 b. TOI-2018 b has a mass and radius that are consistent with an Earthlike core, with a ∼1%-by-mass hydrogen/helium envelope or an ice–rock mixture. The mass of TOI-2018 b is close to the threshold for runaway accretion and hence giant planet formation. Such a threshold is predicted to be around 10 M _⊕ or lower for a low-metallicity (low-opacity) environment. If TOI-2018 b is a planetary core that failed to undergo runaway accretion, it may underline the reason why giant planets are rare around low-metallicity host stars (one possibility is their shorter disk lifetimes). With a K -band magnitude of 7.1, TOI-2018 b may be a suitable target for transmission spectroscopy with the James Webb Space Telescope. The system is also amenable to metastable Helium observation; the detection of a Helium exosphere would help distinguish between a H/He-enveloped planet and a water world.
Keywords
