KELT-19Ab: A P ∼ 4.6-day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion

Siverd, Robert J. and Collins, Karen A. and Zhou, George ORCID: https://orcid.org/0000-0002-4891-3517 and Quinn, Samuel N. and Gaudi, B. Scott and Stassun, Keivan G. and Johnson, Marshall C. and Bieryla, Allyson and Latham, David W. and Ciardi, David R. and Rodriguez, Joseph E. and Penev, Kaloyan and Pinsonneault, Marc and Pepper, Joshua and Eastman, Jason D. and Relles, Howard and Kielkopf, John F. and Gregorio, Joao and Oberst, Thomas E. and Aldi, Giulio Francesco and Esquerdo, Gilbert A. and Calkins, Michael L. and Berlind, Perry and Dressing, Courtney D. and Patel, Rahul and Stevens, Daniel J. and Beatty, Thomas G. and Lund, Michael B. and Labadie-Bartz, Jonathan and Kuhn, Rudolf B. and Colon, Knicole D. and James, David and Yao, Xinyu and Johnson, John A. and Wright, Jason T. and McCrady, Nate and Wittenmyer, Robert A. and Johnson, Samson A. and Sliski, David H. and Jensen, Eric L. N. and Cohen, David H. and McLeod, Kim K. and Penny, Matthew T. and Joner, Michael D. and Stephens, Denise C. and Villanueva, Steven, Jr. and Zambelli, Roberto and Stockdale, Christopher and Evans, Phil and Tan, Thiam-Guan and Curtis, Ivan A. and Reed, Phillip A. and Trueblood, Mark and Trueblood, Patricia (2017) KELT-19Ab: A P ∼ 4.6-day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion. The Astronomical Journal, 155 (1):35. pp. 1-18. ISSN 0004-6256

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Abstract

We present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V ∼ 9.9) A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of radial velocities, which limit the mass to ≳4.1 MJ (3s), and a clear Doppler tomography signal, which indicates a retrograde projected spin-orbit misalignment of λ = -179.7-3.8 +3.7 degrees. Global modeling indicates that the Teff = 7500 ±110 K host star has M M = 1.62+0.20 -0.25 and R = 1.83 0.10 R. The planet has a radius of RP = 1.91 0.11 RJ and receives a stellar insolation flux of ∼ 3.2 10 erg s-1 cm-2, leading to an inferred equilibrium temperature of Teq ∼ 1935 K assuming zero albedo and complete heat redistribution. With a v I sin 84.8 ±2.0 km s = -1, the host is relatively slowly rotating compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic elements but deficient in calcium, suggesting that it is likely an Am star. KELT-19A would be the first detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late-G9V/early-K1V spectral type at a projected separation of »160 au. Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary. However, it may have emplaced the transiting planetary companion via the Kozai-Lidov mechanism.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 08 Feb 2022 04:07
Last Modified: 14 Feb 2022 00:20
Uncontrolled Keywords: methods: observational; planets and satellites: detection; planets; and satellites: gaseous planets; techniques: photometric; techniques:; radial velocities; techniques: spectroscopic; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.3847/1538-3881/aa9e4d
URI: http://eprints.usq.edu.au/id/eprint/45029

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