KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System

Johnson, Marshall C.; Rodriguez, Joseph E.; Zhou, George; Gonzales, Erica J.; Cargile, Phillip A.; Crepp, Justin R.; Penev, K.; Stassun, Keivan G.; Gaudi, B. Scott; Colón, Knicole D.; Stevens, Daniel J.; Strassmeier, K. G.; Ilyin, I.; Collins, Karen A.; Kielkopf, John F.; Oberst, Thomas E.; Maritch, Luke; Reed, Phillip A.; Gregorio, J.; Bozza, V.; Novati, S. Calchi; D’Ago, G.; Scarpetta, G.; Zambelli, Roberto; Latham, David W.; Bieryla, Allyson; Cochran, William D.; Endl, Michael; Tayar, Jamie; Serenelli, Aldo; Aguirre, V. Silva; Clarke, Seth; Martínez, Manuel Martínez; Spencer, M.; Trump, Jason B.; Joner, M. D.; Bugg, Adam G.; Hintz, E. G.; Stephens, Denise C.; Arredondo, Anicia; Benzaid, Anissa; Yazdi, Sormeh; McLeod, Kim K.; Jensen, Eric L. N.; Hancock, Daniel A.; Sorber, Rebecca L.; Kasper, David; Jang‐Condell, Hannah; Beatty, Thomas G.; Carroll, T. A.; Eastman, Jason D.; James, D. J.; Kuhn, Rudolf B.; Labadie-Bartz, Jonathan; Lund, Michael B.; Mallonn, M.; Pepper, Joshua; Siverd, Robert J.; Yao, Xinyu; Cohen, David H.; Curtis, Ivan A.; DePoy, D. L.; Fulton, Benjamin J.; Penny, Matthew T.; Relles, Howard M.; Stockdale, C. J.; Tan, Thiam Guan; Villanueva, Steven

doi:10.3847/1538-3881/aaa5af

Cited by 64 publications

(57 citation statements)

References 116 publications

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“…Based on our calculations (e.g., Figures 4 and 5) we predict that the spin period of WASP-12, upon consumption of this planet, may decrease by a factor of two (prograde orbit), or would be completely flipped (retrograde orbit). Additional planets that are estimated to be on decaying orbits have also been observed (e.g., Gaudi et al 2017;Johnson et al 2018;Labadie-Bartz et al 2019;Johns et al 2019;Rodriguez et al 2019).…”

Section: Discussionmentioning

confidence: 99%

Eating Planets for Lunch and Dinner: Signatures of Planet Consumption by Evolving Stars

Stephan

Naoz

Gaudi

et al. 2020

ApJ

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Exoplanets have been observed around stars at all stages of stellar evolution, in many cases orbiting in configurations that will eventually lead to the planets being engulfed or consumed by their host stars, such as Hot Jupiters or ultra-short period planets. Furthermore, objects such as polluted white dwarfs provide strong evidence that the consumption of planets by stars is a common phenomenon. This consumption causes several significant changes in the stellar properties, such as changes to the stellar spin, luminosity, chemical composition, or mass loss processes. Here, we explore this wide variety of effects for a comprehensive range of stellar and planetary masses and stages of stellar evolution, from the main sequence over red giants to the white dwarfs. We determine that planet consumption can cause transient luminosity features that last on the order of centuries to millennia, and that the post-consumption stellar spins can often reach break-up speeds. Furthermore, stellar moss loss can be caused by this spin-up, as well as through surface grazing interactions, leading to to the formation of unusual planetary nebula shapes or collimated stellar gas ejections. Our results highlight several observable stellar features by which the presence or previous existence of a planet around a given star can be deduced. This will provide future observational campaigns with the tools to better constrain exoplanet demographics, as well as planetary formation and evolution histories.

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Section: Discussionmentioning

confidence: 99%

Eating Planets for Lunch and Dinner: Signatures of Planet Consumption by Evolving Stars

Stephan

Naoz

Gaudi

et al. 2020

ApJ

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“…However, HR 5183 is younger and more metalrich than typical galactic halo objects (Carollo et al 2016), which led us to scrutinize this claim. To investigate HD 5183's galactic population membership, we performed a kinematic analysis of its galactic orbit, following Johnson et al (2018). We used the galpy 2 package (Bovy 2015) to compute 50 random realizations of galactic positions and U,V,W space velocities for HR 5183 consistent with its Gaia DR2 parameters (Gaia Collaboration et al 2018).…”

Section: Stellar Propertiesmentioning

confidence: 99%

Radial Velocity Discovery of an Eccentric Jovian World Orbiting at 18 au

Blunt

Endl

Weiss

et al. 2019

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Based on two decades of radial velocity (RV) observations using Keck/HIRES and McDonald/Tull, and more recent observations using the Automated Planet Finder, we found that the nearby star HR 5183 (HD 120066) hosts a 3M J minimum mass planet with an orbital period of 74 +43 −22 years. The orbit is highly eccentric (e 0.84), shuttling the planet from within the orbit of Jupiter to beyond the orbit of Neptune. Our careful survey design enabled high cadence observations before, during, and after the planet's periastron passage, yielding precise orbital parameter constraints. We searched for stellar or planetary companions that could have excited the planet's eccentricity, but found no candidates, potentially implying that the perturber was ejected from the system. We did identify a bound stellar companion more than 15,000 au from the primary, but reasoned that it is currently too widely separated to have an appreciable effect on HR 5183 b. Because HR 5183 b's wide orbit takes it more than 30 au (1") from its star, we also explored the potential of complimentary studies with direct imaging or stellar astrometry. We found that a Gaia detection is very likely, and that imaging at 10 µm is a promising avenue. This discovery highlights the value of long-baseline RV surveys for discovering and characterizing long-period, eccentric Jovian planets. This population may offer important insights into the dynamical evolution of planetary systems containing multiple massive planets.

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“…Although the number is still not many (∼20), planets around hot (T eff > 7000 K) stars have been discovered by transit surveys like WASP (Wide Angle Search for Planets, Collier Cameron et al 2007) and KELT (Kilodegree Extremely Little Telescope, Pepper et al 2007). Despite the small number, we have learned that they tend to have a wide range of projected spin-orbit obliquities (Johnson et al 2018). Because hot stars are generally rapidly-rotating, they make themselves more oblate, which makes their orbital nodal precessions faster.…”

Section: Introductionmentioning

confidence: 99%

Doppler tomographic measurement of the nodal precession of WASP-33b

Watanabe

Narita

Johnson

2020

Publications of the Astronomical Society of Japan

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WASP-33b is a retrograde hot Jupiter with a period of 1.2 days orbiting around a rapidly rotating and pulsating A-type star. A previous study found that the transit chord of WASP-33b had changed slightly from 2008 to 2014 based on Doppler tomographic measurements. They attributed the change to orbital precession caused by the non-zero oblateness of the host star and the misaligned orbit. We aim to confirm and more precisely model the precession behavior using additional Doppler tomographic data of WASP-33b obtained with the High Dispersion Spectrograph on the 8.2m Subaru telescope in 2011, as well as the datasets used in the previous study. Using equations of a long-term orbital precession, we constrain the stellar gravitational quadrupole moment J 2 = (9.14 ± 0.51) × 10 −5 and the angle between the stellar spin axis and the line of sight i ⋆ = 96 +10 −14 deg. These values update that the host star is more spherical and viewed more equator than the previous study. We also estimate that the precession period is ∼840 years. We also find that the precession amplitude of WASP-33b is ∼67 deg and WASP-33b transits in front of the host star for only ∼20% of the whole precession period.

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KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System

Cited by 64 publications

References 116 publications

Eating Planets for Lunch and Dinner: Signatures of Planet Consumption by Evolving Stars

Eating Planets for Lunch and Dinner: Signatures of Planet Consumption by Evolving Stars

Radial Velocity Discovery of an Eccentric Jovian World Orbiting at 18 au

Doppler tomographic measurement of the nodal precession of WASP-33b

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