A sub-Neptune transiting the young field star HD 18599  at 40 pc. Issue 1 (27th March 2023)

• Record Type: Journal Article
• Authors: de Leon, J P; Livingston, J H; Jenkins, J S; Vines, J I; Wittenmyer, R A; Clark, J T; Winn, J I M; Addison, B; Ballard, S; Bayliss, D; Beichman, C; Benneke, B; Berardo, D A; Bowler, B P; Brown, T; Bryant, E M; Christiansen, J; Ciardi, D; Collins, K A; Collins, K I; Crossfield, I; Deming, D; Dragomir, D; Dressing, C D; Fukui, A; Gan, T; Giacalone, S; Gill, S; Gorjian, V; González Alvarez, E; Hesse, K; Horner, J; Howell, S B; Jenkins, J M; Kane, S R; Kendall, A; Kielkopf, J F; Kreidberg, L; Latham, D W; Liu, H; Lund, M B; Matson, R; Matthews, E; Mengel, M W; Morales, F; Mori, M; Narita, N; Nishiumi, T; Okumura, J; Plavchan, P; Quinn, S; Rabus, M; Ricker, G; Rudat, A; Schlieder, J; Schwarz, R P; Seager, S; Shporer, A; Smith, A M S; Stassun, K; Tamura, M; Tan, T G; Tinney, C; Vanderspek, R; Werner, M W; West, R G; Wright, D; Zhang, H; Zhou, G;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 522:Issue 1(2023)
• Page Start: 750
• Page End: 766
• Publication Date: 2023-03-27
• Subjects: techniques: radial velocities -- techniques: spectroscopic -- planets and satellites: detection -- stars: individual: TOI-179; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stad894
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of planet formation and evolution. However, to date only a handful of stars with age <1 Gyr have been found to host transiting exoplanets. Here we present the discovery and validation of a sub-Neptune around HD 18599 , a young (300 Myr), nearby ( d = 40 pc) K star. We validate the transiting planet candidate as a bona fide planet using data from the TESS , Spitzer , and Gaia missions, ground-based photometry from IRSF , LCO , PEST , and NGTS , speckle imaging from Gemini, and spectroscopy from CHIRON , NRES , FEROS , and Minerva -Australis . The planet has an orbital period of 4.13 d , and a radius of 2.7 R ⊕ . The RV data yields a 3-σ mass upper limit of 30.5 M ⊕ which is explained by either a massive companion or the large observed jitter typical for a young star. The brightness of the host star ( V ∼9 mag) makes it conducive to detailed characterization via Doppler mass measurement which will provide a rare view into the interior structure of young planets.