The Multiplanet System TOI-421

Carleo, Ilaria; Gandolfi, Davide; Barragán, Oscar; Livingston, John H.; Persson, Carina M.; Lam, Kristine W. F.; Vidotto, Aline; Lund, Michael B.; D'Angelo, Carolina Villarreal; Collins, Karen A.; Fossati, Luca; Howard, Andrew W.; Kubyshkina, Daria; Brahm, Rafael; Oklopčić, Antonija; Mollière, Paul; Redfield, Seth; Serrano, Luisa Maria; Dai, Fei; Fridlund, Malcolm; Borsa, Francesco; Korth, Judith; Esposito, Massimiliano; Díaz, Matías R.; Nielsen, Louise Dyregaard; Hellier, Coel; Mathur, Savita; Deeg, Hans J.; Hatzes, Artie P.; Benatti, Serena; Rodler, Florian; Alarcon, Javier; Spina, Lorenzo; Santos, Ângela R. G.; Georgieva, Iskra; García, Rafael A.; González-Cuesta, Lucía; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Albrecht, Simon; Batalha, Natalie M.; Beard, Corey; Boyd, Patricia T.; Bouchy, François; Burt, Jennifer A.; Butler, R. Paul; Cabrera, Juan; Chontos, Ashley; Ciardi, David R.; Cochran, William D.; Collins, Kevin I.; Crane, Jeffrey D.; Crossfield, Ian; Csizmadia, Szilard; Dragomir, Diana; Dressing, Courtney; Eigmüller, Philipp; Endl, Michael; Erikson, Anders; Espinoza, Nestor; Fausnaugh, Michael; Feng, Fabo; Flowers, Erin; Fulton, Benjamin; Gonzales, Erica J.; Grieves, Nolan; Grziwa, Sascha; Guenther, Eike W.; Guerrero, Natalia M.; Henning, Thomas; Hidalgo, Diego; Hirano, Teruyuki; Hjorth, Maria; Huber, Daniel; Isaacson, Howard; Jones, Matias; Jordán, Andrés; Kabáth, Petr; Kane, Stephen R.; Knudstrup, Emil; Lubin, Jack; Luque, Rafael; Mireles, Ismael; Narita, Norio; Nespral, David; Niraula, Prajwal; Nowak, Grzegorz; Palle, Enric; Pätzold, Martin; Petigura, Erik A.; Prieto-Arranz, Jorge; Rauer, Heike; Robertson, Paul; Rose, Mark E.; Roy, Arpita; Sarkis, Paula et al.
Referencia bibliográfica

The Astronomical Journal

Fecha de publicación:
9
2020
Número de autores
113
Número de autores del IAC
10
Número de citas
20
Número de citas referidas
18
Descripción
We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V = 9.9) G9 dwarf star in a visual binary system observed by the Transiting Exoplanet Survey Satellite (TESS) space mission in Sectors 5 and 6. We performed ground-based follow-up observations—comprised of Las Cumbres Observatory Global Telescope transit photometry, NIRC2 adaptive optics imaging, and FIbre-fed Echellé Spectrograph, CORALIE, High Accuracy Radial velocity Planet Searcher, High Resolution Échelle Spectrometer, and Planet Finder Spectrograph high-precision Doppler measurements—and confirmed the planetary nature of the 16 day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of five days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the inner mini-Neptune, TOI-421 b, has an orbital period of Pb = 5.19672 ± 0.00049 days, a mass of Mb = 7.17 ± 0.66 M⊕, and a radius of Rb = ${2.68}_{-0.18}^{+0.19}$ R⊕, whereas the outer warm Neptune, TOI-421 c, has a period of Pc = 16.06819 ± 0.00035 days, a mass of Mc = ${16.42}_{-1.04}^{+1.06}$ M⊕, a radius of Rc = ${5.09}_{-0.15}^{+0.16}$ R⊕, and a density of ρc = ${0.685}_{-0.072}^{+0.080}$ g cm-3. With its characteristics, the outer planet (ρc = ${0.685}_{-0.072}^{+0.080}$ g cm-3) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421 b and TOI-421 c are found to be well-suited for atmospheric characterization. Our atmospheric simulations predict significant Lyα transit absorption, due to strong hydrogen escape in both planets, as well as the presence of detectable CH4 in the atmosphere of TOI-421 c if equilibrium chemistry is assumed. * Based on observations made with ESO Telescopes at the La Silla Observatory under programs ID 1102.C-0923, 0103.C-0874, 0103.C-0759, 0103.C-0442, and 60.A-970. Based on observations obtained with the Nordic Optical Telescope (NOT), operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos (ORM) of the Instituto de Astrofísica de Canarias (IAC). This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This work makes use of observations from the LCOGT network.
Proyectos relacionados
Helio and Asteroseismologia
Sismología Solar y Estelar y Búsqueda de Exoplanetas

Los objetivos genéricos de este Proyecto son: 1) el estudio de la estructura y dinámica del interior solar, 2) la extensión de dicho estudio al caso de otras estrellas, 3) la búsqueda y caracterización de planetas extrasolares por métodos fotométricos (principalmente mediante el método de tránsitos) y espectroscópico (variaciones en la velocidad

Savita
Mathur
Image withthe projects' name
Exoplanetas y Astrobiología

La búsqueda de vida en el Universo se ha visto impulsada por los recientes descubrimientos de planetas alrededor de otras estrellas (los llamados exoplanetas), convirtiéndose en uno de los campos más activos dentro de la Astrofísica moderna. En los últimos años los descubrimientos cada vez más numerosos de nuevos exoplanetas y los últimos avances

Enric
Pallé Bago