TY - JOUR
T1 - TESS Spots a Super-puff
T2 - The Remarkably Low Density of TOI-1420b
AU - Yoshida, Stephanie
AU - Vissapragada, Shreyas
AU - Latham, David W.
AU - Bieryla, Allyson
AU - Thorngren, Daniel P.
AU - Eastman, Jason D.
AU - López-Morales, Mercedes
AU - Barkaoui, Khalid
AU - Beichman, Charles
AU - Berlind, Perry
AU - Buchave, Lars A.
AU - Calkins, Michael L.
AU - Ciardi, David R.
AU - Collins, Karen A.
AU - Cosentino, Rosario
AU - Crossfield, Ian J.M.
AU - Dai, Fei
AU - DiTomasso, Victoria
AU - Dowling, Nicholas
AU - Esquerdo, Gilbert A.
AU - Forés-Toribio, Raquel
AU - Ghedina, Adriano
AU - Goliguzova, Maria V.
AU - Golub, Eli
AU - Gonzales, Erica J.
AU - Horta, Ferran Grau
AU - Higuera, Jesus
AU - Hoch, Nora
AU - Horne, Keith
AU - Howell, Steve B.
AU - Jenkins, Jon M.
AU - Klusmeyer, Jessica
AU - Laloum, Didier
AU - Lissauer, Jack J.
AU - Logsdon, Sarah E.
AU - Malavolta, Luca
AU - Matson, Rachel A.
AU - Matthews, Elisabeth C.
AU - McLeod, Kim K.
AU - Medina, Jennifer V.
AU - Muñoz, Jose A.
AU - Osborn, Hugh P.
AU - Safonov, Boris
AU - Schlieder, Joshua
AU - Schmidt, Michael
AU - Schweiker, Heidi
AU - Seager, Sara
AU - Sozzetti, Alessandro
AU - Srdoc, Gregor
AU - Stefánsson, Guđmundur
AU - Strakhov, Ivan A.
AU - Striegel, Stephanie
AU - Villaseñor, Joel
AU - Winn, Joshua N.
N1 - Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/11/1
Y1 - 2023/11/1
N2 - We present the discovery of TOI-1420b, an exceptionally low-density (ρ = 0.08 ± 0.02 g cm−3) transiting planet in a P = 6.96 days orbit around a late G-dwarf star. Using transit observations from TESS, LCOGT, Observatoire Privé du Mont, Whitin, Wendelstein, OAUV, Ca l’Ou, and KeplerCam, along with radial velocity observations from HARPS-N and NEID, we find that the planet has a radius of R p = 11.9 ± 0.3R ⊕ and a mass of M p = 25.1 ± 3.8M ⊕. TOI-1420b is the largest known planet with a mass less than 50M ⊕, indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b’s envelope mass fraction to be f env = 82 − 6 + 7 % , suggesting that runaway gas accretion occurred when its core was at most four to five times the mass of the Earth. TOI-1420b is similar to the planet WASP-107b in mass, radius, density, and orbital period, so a comparison of these two systems may help reveal the origins of close-in low-density planets. With an atmospheric scale height of 1950 km, a transmission spectroscopy metric of 580, and a predicted Rossiter-McLaughlin amplitude of about 17 m s−1, TOI-1420b is an excellent target for future atmospheric and dynamical characterization.
AB - We present the discovery of TOI-1420b, an exceptionally low-density (ρ = 0.08 ± 0.02 g cm−3) transiting planet in a P = 6.96 days orbit around a late G-dwarf star. Using transit observations from TESS, LCOGT, Observatoire Privé du Mont, Whitin, Wendelstein, OAUV, Ca l’Ou, and KeplerCam, along with radial velocity observations from HARPS-N and NEID, we find that the planet has a radius of R p = 11.9 ± 0.3R ⊕ and a mass of M p = 25.1 ± 3.8M ⊕. TOI-1420b is the largest known planet with a mass less than 50M ⊕, indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b’s envelope mass fraction to be f env = 82 − 6 + 7 % , suggesting that runaway gas accretion occurred when its core was at most four to five times the mass of the Earth. TOI-1420b is similar to the planet WASP-107b in mass, radius, density, and orbital period, so a comparison of these two systems may help reveal the origins of close-in low-density planets. With an atmospheric scale height of 1950 km, a transmission spectroscopy metric of 580, and a predicted Rossiter-McLaughlin amplitude of about 17 m s−1, TOI-1420b is an excellent target for future atmospheric and dynamical characterization.
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U2 - 10.3847/1538-3881/acf858
DO - 10.3847/1538-3881/acf858
M3 - Article
AN - SCOPUS:85174388265
SN - 0004-6256
VL - 166
JO - Astronomical Journal
JF - Astronomical Journal
IS - 5
M1 - 181
ER -