KELT-12b: A $P \sim 5$ Day, Highly Inflated Hot Jupiter Transiting a Mildly Evolved Hot Star
Daniel J. Stevens, Karen A. Collins, B. Scott Gaudi, Thomas G. Beatty, Robert J. Siverd, Allyson Bieryla, Benjamin J. Fulton, Justin R. Crepp, Erica J. Gonzales… 展开作者
Daniel J. Stevens, Karen A. Collins, B. Scott Gaudi, Thomas G. Beatty, Robert J. Siverd, Allyson Bieryla, Benjamin J. Fulton, Justin R. Crepp, Erica J. Gonzales, Carl T. Coker, Kaloyan Penev, Keivan G. Stassun, Eric L. N. Jensen, Andrew W. Howard, David W. Latham, Joseph E. Rodriguez, Roberto Zambelli, Valerio Bozza, Phillip A. Reed, Joao Gregorio, Lars A. Buchhave, Matthew T. Penny, Joshua Pepper, Perry Berlind, Sebastiano Calchi Novati, Michael L. Calkins, Giuseppe D'Ago, Jason D. Eastman, D. Bayliss, Knicole D. Colón, Ivan A. Curtis, D. L. DePoy, Gilbert A. Esquerdo, Andrew Gould, Michael D. Joner, John F. Kielkopf, Jonathan Labadie-Bartz, Michael B. Lund, Mark Manner, Jennifer L. Marshall, Kim K. McLeod, Thomas E. Oberst, Richard W. Pogge, Gaetano Scarpetta, Denise C. Stephens, Christopher Stockdale, T. G. Tan, Mark Trueblood, Patricia Trueblood
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16 pages, 14 figures, 6 tables. Submitted to AAS Journals
We report the discovery of KELT-12b, a highly inflated Jupiter-mass planet transiting a mildly evolved host star. We identified the initial transit signal in the KELT-North survey data and established the planetary nature of the companion through precise follow-up photometry, high-resolution spectroscopy, precise radial velocity measurements, and high-resolution adaptive optics imaging. Our preferred best-fit model indicates that the $V = 10.64$ host, TYC 2619-1057-1, has $T_{\rm eff} = 6278 \pm 51$ K, $\log{g_\star} = 3.89^{+0.054}_{-0.051}$, and [Fe/H] = $0.19^{+0.083}_{-0.085}$, with an inferred mass $M_{\star} = 1.59^{+0.071}_{-0.091} M_\odot$ and radius $R_\star = 2.37 \pm 0.18 R_\odot$. The planetary companion has $M_{\rm P} = 0.95 \pm 0.14 M_{\rm J}$, $R_{\rm P} = 1.79^{+0.18}_{-0.17} R_{\rm J}$, $\log{g_{\rm P}} = 2.87^{+0.097}_{-0.098}$, and density $ρ_{\rm P} = 0.21^{+0.075}_{-0.054}$ g cm$^{-3}$, making it one of the most inflated giant planets known. The time of inferior conjunction in ${\rm BJD_{TDB}}$ is $2457088.692055 \pm 0.0009$ and the period is $P = 5.0316144 \pm 0.0000306$ days. Despite the relatively large separation of $\sim0.07$ AU implied by its $\sim 5.03$-day orbital period, KELT-12b receives significant flux of $2.93^{+0.33}_{-0.30} \times 10^9$ erg s$^{-1}$ cm$^{-2}$ from its host. We compare the radii and insolations of transiting gas-giant planets around hot ($T_{\rm eff} \geq 6250$ K) and cool stars, noting that the observed paucity of known transiting giants around hot stars with low insolation is likely due to selection effects. We underscore the significance of long-term ground-based monitoring of hot stars and space-based targeting of hot stars with the Transiting Exoplanet Survey Satellite (TESS) to search for inflated giants in longer-period orbits.
KELT-6b: A P~7.9 d Hot Saturn Transiting a Metal-Poor Star with a Long-Period Companion
We report the discovery of KELT-6b, a mildly-inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V=10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T_eff=6102 \pm 43 K, log(g_*)=4.07_{-0.07}^{+0.04} and [Fe/H]…
