@article{42670023f1764f2b8f75cee2d7f12feb,
title = "HD 56414 b: A Warm Neptune Transiting an A-type Star",
abstract = "We report the discovery in TESS data and validation of HD 56414 b (a.k.a. TOI-1228 b), a Neptune-size (R p = 3.71 ± 0.20 R ⊕) planet with a 29 day orbital period transiting a young (age = 420 ± 140 Myr) A-type star in the TESS southern continuous-viewing zone. HD 56414 is one of the hottest stars (T eff = 8500 ± 150 K) to host a known sub-Jovian planet. HD 56414 b lies on the boundary of the hot Neptune desert in the planet radius-bolometric insolation flux space, suggesting that the planet may be experiencing mass loss. To explore this, we apply a photoevaporation model that incorporates the high near-ultraviolet continuum emission of A-type stars. We find that the planet can retain most of its atmosphere over the typical 1 Gyr main-sequence lifetime of an A-type star if its mass is ≥8 M ⊕. Our model also predicts that close-in Neptune-size planets with masses <14 M ⊕ are susceptible to total atmospheric stripping over 1 Gyr, hinting that the hot Neptune desert, which has been previously observed around FGKM-type stars, likely extends to A-type stars.",
author = "Steven Giacalone and Dressing, {Courtney D.} and Mu{\~n}oz, {A. Garc{\'i}a} and Hooton, {Matthew J.} and Stassun, {Keivan G.} and Quinn, {Samuel N.} and George Zhou and Carl Ziegler and Roland Vanderspek and Latham, {David W.} and S. Seager and Winn, {Joshua N.} and Jenkins, {Jon M.} and C{\'e}sar Brice{\~n}o and Huang, {Chelsea X.} and Rodriguez, {David R.} and Avi Shporer and Mann, {Andrew W.} and David Watanabe and Bill Wohler",
note = "Funding Information: We thank Eugene Chiang for the constructive conversations that led to the analyses in this paper. This work is supported by NASA FINESST award 80NSSC20K1549 (FI: Giacalone, PI: Dressing). C.D.D. also acknowledges support provided by the David and Lucile Packard Foundation via grant 2019-69648. S.Q. acknowledges support from the TESS GI Program under award 80NSSC21K1056. G.Z. thanks the support of the ARC DECRA program DE210101893. Based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Minist{\'e}rio da Ci{\^e}ncia, Tecnologia e Inova{\c c}{\~o}es (MCTI/LNA) do Brasil, the US National Science Foundation{\textquoteright}s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. The TESS data utilized in this paper were collected thanks to the following TESS GI Programs: G03278 (PI: Mayo), G03255 (PI: Huber), G03068 (PI: Kipping), and G03252 (PI: Hambleton). Funding Information: We thank Eugene Chiang for the constructive conversations that led to the analyses in this paper. This work is supported by NASA FINESST award 80NSSC20K1549 (FI: Giacalone, PI: Dressing). C.D.D. also acknowledges support provided by the David and Lucile Packard Foundation via grant 2019-69648. S.Q. acknowledges support from the TESS GI Program under award 80NSSC21K1056. G.Z. thanks the support of the ARC DECRA program DE210101893. Based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Minist{\'e}rio da Ci{\^e}ncia, Tecnologia e Inova{\c c}{\~o}es (MCTI/LNA) do Brasil, the US National Science Foundation{\textquoteright}s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. The TESS data utilized in this paper were collected thanks to the following TESS GI Programs: G03278 (PI: Mayo), G03255 (PI: Huber), G03068 (PI: Kipping), and G03252 (PI: Hambleton). Publisher Copyright: {\textcopyright} 2022. The Author(s). Published by the American Astronomical Society.",
year = "2022",
month = aug,
day = "1",
doi = "10.3847/2041-8213/ac80f4",
language = "English (US)",
volume = "935",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",
}