Aarhus University Seal / Aarhus Universitets segl

Anders Bo Justesen

A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisLetterForskningpeer review

DOI

  • Aldo S. Bonomo, Napoli Capodimonte
  • ,
  • Li Zeng, Harvard University
  • ,
  • Mario Damasso, Napoli Capodimonte
  • ,
  • Zoë M. Leinhardt, Bristol University
  • ,
  • Anders B. Justesen
  • Eric Lopez, NASA Goddard Space Flight Center
  • ,
  • Mikkel N. Lund
  • Luca Malavolta, Università degli Studi di Padova, INAF - Osservatorio Astronomico di Padova
  • ,
  • Victor Silva Aguirre
  • Lars A. Buchhave, Technical University of Denmark
  • ,
  • Enrico Corsaro, Osservatorio Astrofisico di Catania
  • ,
  • Thomas Denman, Bristol University
  • ,
  • Mercedes Lopez-Morales, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Sean M. Mills, California Institute of Technology
  • ,
  • Annelies Mortier, University of St. Andrews
  • ,
  • Ken Rice, University of Edinburgh, Institute for Astronomy
  • ,
  • Alessandro Sozzetti, Napoli Capodimonte
  • ,
  • Andrew Vanderburg, Harvard-Smithsonian Center for Astrophysics, University of Texas, Austin, Texas
  • ,
  • Laura Affer, INAF—Osservatorio Astronomico di Palermo
  • ,
  • Torben Arentoft
  • Mansour Benbakoura, Université Paris-Saclay, Université Paris—Denis Diderot
  • ,
  • François Bouchy, Université de Genève
  • ,
  • Jørgen Christensen-Dalsgaard
  • Andrew Collier Cameron, University of St. Andrews
  • ,
  • Rosario Cosentino, INAF—Fundación Galileo Galilei
  • ,
  • Courtney D. Dressing, UC Berkeley
  • ,
  • Xavier Dumusque, Université de Genève
  • ,
  • Pedro Figueira, European Southern Observatory Santiago, CAUP
  • ,
  • Aldo F.M. Fiorenzano, INAF—Fundación Galileo Galilei
  • ,
  • Rafael A. García, Université Paris-Saclay, Université Paris—Denis Diderot
  • ,
  • Rasmus Handberg
  • Avet Harutyunyan, INAF—Fundación Galileo Galilei
  • ,
  • John A. Johnson, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Hans Kjeldsen
  • David W. Latham, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Christophe Lovis, Université de Genève
  • ,
  • Mia S. Lundkvist
  • Savita Mathur, La Laguna University, Instituto de Astrofísica de Canarias
  • ,
  • Michel Mayor, Université de Genève
  • ,
  • Giusi Micela, INAF—Osservatorio Astronomico di Palermo
  • ,
  • Emilio Molinari, Osservatorio Astronomico di Cagliari
  • ,
  • Fatemeh Motalebi, Université de Genève
  • ,
  • Valerio Nascimbeni, Università degli Studi di Padova, INAF - Osservatorio Astronomico di Padova
  • ,
  • Chantanelle Nava, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Francesco Pepe, Université de Genève
  • ,
  • David F. Phillips, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Giampaolo Piotto, Università degli Studi di Padova, INAF - Osservatorio Astronomico di Padova
  • ,
  • Ennio Poretti, INAF—Fundación Galileo Galilei, Osservatorio Astronomico di Brera
  • ,
  • Dimitar Sasselov, Harvard-Smithsonian Center for Astrophysics
  • ,
  • Damien Ségransan, Université de Genève

Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii (R ) range from low-density sub-Neptunes containing volatile elements 1 to higher-density rocky planets with Earth-like 2 or iron-rich 3 (Mercury-like) compositions. Such astonishing diversity in observed small exoplanet compositions may be the product of different initial conditions of the planet-formation process or different evolutionary paths that altered the planetary properties after formation 4 . Planet evolution may be especially affected by either photoevaporative mass loss induced by high stellar X-ray and extreme ultraviolet (XUV) flux 5 or giant impacts 6 . Although there is some evidence for the former 7,8 , there are no unambiguous findings so far about the occurrence of giant impacts in an exoplanet system. Here, we characterize the two innermost planets of the compact and near-resonant system Kepler-107 (ref. 9 ). We show that they have nearly identical radii (about 1.5–1.6R ), but the outer planet Kepler-107 c is more than twice as dense (about 12.6 g cm –3 ) as the innermost Kepler-107 b (about 5.3 g cm −3 ). In consequence, Kepler-107 c must have a larger iron core fraction than Kepler-107 b. This imbalance cannot be explained by the stellar XUV irradiation, which would conversely make the more-irradiated and less-massive planet Kepler-107 b denser than Kepler-107 c. Instead, the dissimilar densities are consistent with a giant impact event on Kepler-107 c that would have stripped off part of its silicate mantle. This hypothesis is supported by theoretical predictions from collisional mantle stripping 10 , which match the mass and radius of Kepler-107 c.

OriginalsprogEngelsk
TidsskriftNature Astronomy
Vol/bind3
Nummer5
Sider (fra-til)416-423
Antal sider8
DOI
StatusUdgivet - 1 maj 2019

Se relationer på Aarhus Universitet Citationsformater

ID: 154134509