The Evolutionary Track of H/He Envelopes of the Observed Population of Sub-Neptunes and Super-Earths
Tipo
Artigo
Data de publicação
2020
Periódico
Astrophysical Journal
Citações (Scopus)
7
Autores
Estrela R.
Swain M.R.
Gupta A.
Sotin C.
Valio A.
Swain M.R.
Gupta A.
Sotin C.
Valio A.
Orientador
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
© 2020. The American Astronomical Society. All rights reserved..The observational detection of a localized reduction in the small planet occurrence rate, sometimes termed a "gap,"is an exciting discovery because of the implications for planet evolutionary history. This gap appears to define a transition region in which sub-Neptune planets are believed to have lost their H/He envelopes, potentially by photoevaporation or core powered mass loss, and have thus been transformed into bare core terrestrial planets. Here we investigate the transition between sub-Neptunes and super-Earths using a real sample of observed small close-in planets and applying envelope evolution models of the H/He envelope together with the mass-radius diagram and a photoevaporation model. We find that photoevaporation can explain the H/He envelope loss of most super-Earths in 100 Myr, although an additional loss mechanism appears necessary in some planets. We explore the possibility that these planets' families have different core masses and find a continuum in the primordial population of the strongly irradiated super-Earths and the sub-Neptunes. Our analysis also shows that close-orbiting sub-Neptunes with R < 3.5 R ⊕ typically lose ∼30% of their primordial envelope.