Gandolfi, Davide; Fossati, Luca; Livingston, John H.; Stassun, Keivan G.; Grziwa, Sascha; Barragán, Oscar; Fridlund, Malcolm; Kubyshkina, Daria; Persson, Carina M.; Dai, Fei; Lam, Kristine W. F.; Albrecht, Simon; Batalha, Natalie; Beck, Paul G.; Justesen, Anders Bo; Cabrera, Juan; Cartwright, Scott; Cochran, William D.; Csizmadia, Szilard; Davies, Misty D.; Deeg, Hans J.; Eigmüller, Philipp; Endl, Michael; Erikson, Anders; Esposito, Massimiliano; García, Rafael A.; Goeke, Robert; González-Cuesta, Lucía; Guenther, Eike W.; Hatzes, Artie P.; Hidalgo, Diego; Hirano, Teruyuki; Hjorth, Maria; Kabath, Petr; Knudstrup, Emil; Korth, Judith; Li, Jie; Luque, Rafael; Mathur, Savita; Montañes Rodríguez, Pilar; Narita, Norio; Nespral, David; Niraula, Prajwal; Nowak, Grzegorz; Palle, Enric; Pätzold, Martin; Prieto-Arranz, Jorge; Rauer, Heike; Redfield, Seth; Ribas, Ignasi; Skarka, Marek; Smith, Alexis M. S.; Rowden, Pamela; Torres, Guillermo; Van Eylen, Vincent; Vezie, Michael L.
Bibliographical reference
The Astrophysical Journal Letters, Volume 876, Issue 2, article id. L24, 12 pp. (2019).
Description
We report the discovery of a super-Earth and a sub-Neptune transiting
the star HD 15337 (TOI-402, TIC 120896927), a bright (V = 9) K1 dwarf
observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors
3 and 4. We combine the TESS photometry with archival High Accuracy
Radial velocity Planet Searcher spectra to confirm the planetary nature
of the transit signals and derive the masses of the two transiting
planets. With an orbital period of 4.8 days, a mass of
{7.51}-1.01+1.09 {M}\oplus and a
radius of 1.64 ± 0.06 R ⊕, HD 15337 b joins the
growing group of short-period super-Earths known to have a rocky
terrestrial composition. The sub-Neptune HD 15337 c has an orbital
period of 17.2 days, a mass of {8.11}-1.69+1.82
{{{M}}}\oplus , and a radius of 2.39 ± 0.12 R
⊕, suggesting that the planet might be surrounded by a
thick atmospheric envelope. The two planets have similar masses and lie
on opposite sides of the radius gap, and are thus an excellent testbed
for planet formation and evolution theories. Assuming that HD 15337 c
hosts a hydrogen-dominated envelope, we employ a recently developed
planet atmospheric evolution algorithm in a Bayesian framework to
estimate the history of the high-energy (extreme ultraviolet and X-ray)
emission of the host star. We find that at an age of 150 Myr, the star
possessed on average between 3.7 and 127 times the high-energy
luminosity of the current Sun.
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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
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
