Bibcode
Cloutier, Ryan; Charbonneau, David; Stassun, Keivan G.; Murgas, Felipe; Mortier, Annelies; Massey, Robert; Lissauer, Jack J.; Latham, David W.; Irwin, Jonathan; Haywood, Raphaëlle D.; Guerra, Pere; Girardin, Eric; Giacalone, Steven A.; Bosch-Cabot, Pau; Bieryla, Allyson; Winn, Joshua; Watson, Christopher A.; Vanderspek, Roland; Udry, Stéphane; Tamura, Motohide; Sozzetti, Alessandro; Shporer, Avi; Ségransan, Damien; Seager, Sara; Savel, Arjun B.; Sasselov, Dimitar; Rose, Mark; Ricker, George; Rice, Ken; Quintana, Elisa V.; Quinn, Samuel N.; Piotto, Giampaolo; Phillips, David; Pepe, Francesco; Pedani, Marco; Parviainen, Hannu; Palle, Enric; Narita, Norio; Molinari, Emilio; Micela, Giuseppina; McDermott, Scott; Mayor, Michel; Matson, Rachel A.; Martinez Fiorenzano, Aldo F.; Lovis, Christophe; López-Morales, Mercedes; Kusakabe, Nobuhiko; Jensen, Eric L. N.; Jenkins, Jon M.; Huang, Chelsea X.; Howell, Steve B.; Harutyunyan, Avet; Fűrész, Gábor; Fukui, Akihiko; Esquerdo, Gilbert A.; Esparza-Borges, Emma; Dumusque, Xavier; Dressing, Courtney D.; Fabrizio, Luca Di; Collins, Karen A.; Cameron, Andrew Collier; Christiansen, Jessie L.; Cecconi, Massimo; Buchhave, Lars A.; Boschin, Walter; Andreuzzi, Gloria
Bibliographical reference
The Astronomical Journal
Advertised on:
8
2021
Citations
28
Refereed citations
27
Description
Studies of close-in planets orbiting M dwarfs have suggested that the M-dwarf radius valley may be well explained by distinct formation timescales between enveloped terrestrials and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally driven mass-loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M-dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short-period planet TOI-1634 b (P = 0.989 days, <?CDATA $F=121{F}_{\oplus }$?> , <?CDATA ${r}_{p}={1.790}_{-0.081}^{+0.080}$?> R⊕) orbiting a nearby M2 dwarf (Ks = 8.7, Rs = 0.450 R⊙, Ms = 0.502 M⊙) and whose size and orbital period sit within the M-dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of <?CDATA ${4.91}_{-0.70}^{+0.68}$?> M⊕, which makes TOI-1634 b inconsistent with an Earth-like composition at <?CDATA $5.9\sigma $?> and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky composition that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of Earth supports the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with <?CDATA ${M}_{s}\lesssim 0.5$?> M⊙.
Related projects
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Enric
Pallé Bago