| Autor: |
Yoshida, Stephanie, Vissapragada, Shreyas, Latham, David W., Bieryla, Allyson, Thorngren, Daniel P., Eastman, Jason D., López-Morales, Mercedes, Barkaoui, Khalid, Beichmam, Charles, Berlind, Perry, Buchave, Lars A., Calkins, Michael L., Ciardi, David R., Collins, Karen A., Cosentino, Rosario, Crossfield, Ian J. M., Dai, Fei, DiTomasso, Victoria, Dowling, Nicholas, Esquerdo, Gilbert A., Forés-Toribio, Raquel, Ghedina, Adriano, Goliguzova, Maria V., Golub, Eli, Gonzales, Erica J., Horta, Ferran Grau, Higuera, Jesus, Hoch, Nora, Horne, Keith, Howell, Steve B., Jenkins, Jon M., Klusmeyer, Jessica, Laloum, Didier, Lissauer, Jack J., Logsdon, Sarah E., Malavolta, Luca, Matson, Rachel A., Matthews, Elisabeth C., McLeod, Kim K., Medina, Jennifer V., Muñoz, Jose A., Osborn, Hugh P., Safonov, Boris, Schlieder, Joshua, Schmidt, Michael, Schweiker, Heidi, Seager, Sara, Sozzetti, Alessandro, Srdoc, Gregor, Stefánsson, Guđmundur, Strakhov, Ivan A., Striegel, Stephanie, Villaseñor, Joel, Winn, Joshua N. |
| Rok vydání: |
2023 |
| Předmět: |
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| Druh dokumentu: |
Working Paper |
| Popis: |
We present the discovery of TOI-1420b, an exceptionally low-density ($\rho = 0.08\pm0.02$ g cm$^{-3}$) transiting planet in a $P = 6.96$ day orbit around a late G dwarf star. Using transit observations from TESS, LCOGT, OPM, 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 $\pm$ 0.3 $R_\Earth$ and a mass of $M_p$ = 25.1 $\pm$ 3.8 $M_\Earth$. TOI-1420b is the largest-known planet with a mass less than $50M_\Earth$, indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b's envelope mass fraction to be $f_{env} = 82^{+7}_{-6}\%$, suggesting that runaway gas accretion occurred when its core was at most $4-5\times$ 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. |
| Databáze: |
arXiv |
| Externí odkaz: |
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