A super-massive Neptune-sized planet

Luca Naponiello; Luigi Mancini; Alessandro Sozzetti; Aldo S Bonomo; Alessandro Morbidelli; Jingyao Dou; Li Zeng; Zoe M Leinhardt; Katia Biazzo; Patricio E Cubillos; Matteo Pinamonti; Daniele Locci; Antonio Maggio; Mario Damasso; Antonino F Lanza; Jack J Lissauer; Karen A Collins; Philip J Carter; Eric L N Jensen; Andrea Bignamini; Walter Boschin; Luke G Bouma; David R Ciardi; Rosario Cosentino; Ian Crossfield; Silvano Desidera; Xavier Dumusque; Aldo F M Fiorenzano; Akihiko Fukui; Paolo Giacobbe; Crystal L Gnilka; Adriano Ghedina; Gloria Guilluy; Avet Harutyunyan; Steve B Howell; Jon M Jenkins; Michael B Lund; John F Kielkopf; Katie V Lester; Luca Malavolta; Andrew W Mann; Rachel A Matson; Elisabeth C Matthews; Domenico Nardiello; Norio Narita; Emanuele Pace; Isabella Pagano; Enric Palle; Marco Pedani; Sara Seager; Joshua E Schlieder; Richard P Schwarz; Avi Shporer; Joseph D Twicken; Joshua N Winn; Carl Ziegler; Tiziano Zingales

doi:10.1038/s41586-023-06499-2

A super-massive Neptune-sized planet

Nature. 2023 Oct;622(7982):255-260. doi: 10.1038/s41586-023-06499-2. Epub 2023 Aug 30.

Authors

Luca Naponiello^{1

2

3

4}, Luigi Mancini^{5

6

7}, Alessandro Sozzetti⁶, Aldo S Bonomo⁶, Alessandro Morbidelli⁸, Jingyao Dou⁹, Li Zeng^{10

11}, Zoe M Leinhardt⁹, Katia Biazzo¹², Patricio E Cubillos^{6

13}, Matteo Pinamonti⁶, Daniele Locci¹⁴, Antonio Maggio¹⁴, Mario Damasso⁶, Antonino F Lanza¹⁵, Jack J Lissauer^{16

17}, Karen A Collins¹⁰, Philip J Carter⁹, Eric L N Jensen¹⁸, Andrea Bignamini¹⁹, Walter Boschin^{20

21

22}, Luke G Bouma²³, David R Ciardi²³, Rosario Cosentino²⁰, Ian Crossfield²⁴, Silvano Desidera²⁵, Xavier Dumusque²⁶, Aldo F M Fiorenzano²⁰, Akihiko Fukui^{21

27}, Paolo Giacobbe⁶, Crystal L Gnilka^{16

23}, Adriano Ghedina²⁰, Gloria Guilluy⁶, Avet Harutyunyan²⁰, Steve B Howell¹⁶, Jon M Jenkins¹⁶, Michael B Lund²³, John F Kielkopf²⁸, Katie V Lester¹⁶, Luca Malavolta^{25

29}, Andrew W Mann³⁰, Rachel A Matson³¹, Elisabeth C Matthews⁷, Domenico Nardiello²⁵, Norio Narita^{21

27

32}, Emanuele Pace³³, Isabella Pagano¹⁵, Enric Palle^{21

22}, Marco Pedani²⁰, Sara Seager^{11

34

35

36}, Joshua E Schlieder³⁷, Richard P Schwarz¹⁰, Avi Shporer^{34

36}, Joseph D Twicken^{16

38}, Joshua N Winn³⁹, Carl Ziegler⁴⁰, Tiziano Zingales^{25

29}

Affiliations

¹ Department of Physics, University of Rome "Tor Vergata", Rome, Italy. lnaponiello@roma2.infn.it.
² Department of Physics and Astronomy, University of Florence, Florence, Italy. lnaponiello@roma2.infn.it.
³ Department of Physics, Sapienza University of Rome, Rome, Italy. lnaponiello@roma2.infn.it.
⁴ INAF - Turin Astrophysical Observatory, Pino Torinese, Italy. lnaponiello@roma2.infn.it.
⁵ Department of Physics, University of Rome "Tor Vergata", Rome, Italy.
⁶ INAF - Turin Astrophysical Observatory, Pino Torinese, Italy.
⁷ Max Planck Institute for Astronomy, Heidelberg, Germany.
⁸ Laboratoire Lagrange, Université Cote d'Azur, CNRS, Observatoire de la Côte d'Azur, Nice, France.
⁹ School of Physics, H.H. Wills Physics Laboratory, University of Bristol, Bristol, UK.
¹⁰ Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA, USA.
¹¹ Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA.
¹² INAF - Rome Astronomical Observatory, Monte Porzio Catone, Italy.
¹³ Space Research Institute, Austrian Academy of Sciences, Graz, Austria.
¹⁴ INAF - Palermo Astronomical Observatory, Palermo, Italy.
¹⁵ INAF - Catania Astrophysical Observatory, Catania, Italy.
¹⁶ NASA Ames Research Center, Moffett Field, CA, USA.
¹⁷ Department of Earth and Planetary Sciences, Stanford University, Stanford, CA, USA.
¹⁸ Department of Physics & Astronomy, Swarthmore College, Swarthmore, PA, USA.
¹⁹ INAF - Trieste Astronomical Observatory, Trieste, Italy.
²⁰ Fundación Galileo Galilei - INAF, Tenerife, Spain.
²¹ Instituto de Astrofísica de Canarias (IAC), Tenerife, Spain.
²² Departamento de Astrofísica, Universidad de La Laguna (ULL), Tenerife, Spain.
²³ NASA Exoplanet Science Institute - Caltech/IPAC, Pasadena, CA, USA.
²⁴ Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA.
²⁵ INAF - Padova Astronomical Observatory, Padova, Italy.
²⁶ Observatoire de Genève, Université de Genève, Versoix, Switzerland.
²⁷ Komaba Institute for Science, The University of Tokyo, Tokyo, Japan.
²⁸ Department of Physics and Astronomy, University of Louisville, Louisville, KY, USA.
²⁹ Department of Physics and Astronomy, University of Padova, Padova, Italy.
³⁰ Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
³¹ United States Naval Observatory, Washington, DC, USA.
³² Astrobiology Center, Osawa, Mitaka, Japan.
³³ Department of Physics and Astronomy, University of Florence, Florence, Italy.
³⁴ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
³⁵ Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA.
³⁶ Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
³⁷ NASA Goddard Space Flight Center, Greenbelt, MD, USA.
³⁸ SETI Institute, Mountain View, CA, USA.
³⁹ Department of Astrophysical Sciences, Princeton University, Princeton, NJ, USA.
⁴⁰ Department of Physics, Engineering & Astronomy, Stephen F. Austin State University, Nacogdoches, TX, USA.

PMID: 37648866
DOI: 10.1038/s41586-023-06499-2

Abstract

Neptune-sized planets exhibit a wide range of compositions and densities, depending on factors related to their formation and evolution history, such as the distance from their host stars and atmospheric escape processes. They can vary from relatively low-density planets with thick hydrogen-helium atmospheres^1,2 to higher-density planets with a substantial amount of water or a rocky interior with a thinner atmosphere, such as HD 95338 b (ref. ³), TOI-849 b (ref. ⁴) and TOI-2196 b (ref. ⁵). The discovery of exoplanets in the hot-Neptune desert⁶, a region close to the host stars with a deficit of Neptune-sized planets, provides insights into the formation and evolution of planetary systems, including the existence of this region itself. Here we show observations of the transiting planet TOI-1853 b, which has a radius of 3.46 ± 0.08 Earth radii and orbits a dwarf star every 1.24 days. This planet has a mass of 73.2 ± 2.7 Earth masses, almost twice that of any other Neptune-sized planet known so far, and a density of 9.7 ± 0.8 grams per cubic centimetre. These values place TOI-1853 b in the middle of the Neptunian desert and imply that heavy elements dominate its mass. The properties of TOI-1853 b present a puzzle for conventional theories of planetary formation and evolution, and could be the result of several proto-planet collisions or the final state of an initially high-eccentricity planet that migrated closer to its parent star.