KELT-16b: A highly irradiated, ultra-short period hot Jupiter nearing tidal disruption
Creators: name: Oberst, Thomas E.
name: Rodriguez, Joseph E.
name: Colón, Knicole D.
name: Angerhausen, Daniel
name: Bieryla, Allyson
name: Ngo, Henry
name: Stevens, Daniel J.
name: Stassun, Keivan G.
name: Gaudi, B. Scott
name: Pepper, Joshua
name: Penev, Kaloyan
name: Mawet, Dimitri
name: Latham, David W.
name: Heintz, Tyler M.
name: Osei, Baffour W.
name: Collins, Karen A.
name: Kielkopf, John F.
name: Visgaitis, Tiffany
name: Reed, Phillip A.
name: Escamilla, Alejandra
name: Yazdi, Sormeh
name: McLeod, Kim K.
name: Lunsford, Leanne T.
name: Spencer, Michelle
name: Joner, Michael D.
name: Gregorio, Joao
name: Gaillard, Clement
name: Matt, Kyle
name: Dumont, Mary Thea
name: Stephens, Denise C.
name: Cohen, David H.
name: Jensen, Eric L. N.
name: Novati, Sebastiano Calchi
name: Bozza, Valerio
name: Labadie-Bartz, Jonathan
name: Siverd, Robert J.
name: Lund, Michael B.
name: Beatty, Thomas G.
name: Eastman, Jason D.
name: Penny, Matthew T.
name: Manner, Mark
name: Zambelli, Roberto
name: Fulton, Benjamin J.
name: Stockdale, Christopher
name: DePoy, D. L.
name: Marshall, Jennifer L.
name: Pogge, Richard W.
name: Gould, Andrew
name: Trueblood, Mark
name: Trueblood, Patricia
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright ($V = 11.7$) star TYC 2688-1839-1. A global analysis of the system shows KELT-16 to be an F7V star with $T_\textrm{eff} = 6236\pm54$ K, $\log{g_\star} = 4.253_{-0.036}^{+0.031}$, [Fe/H] = -0.002$_{-0.085}^{+0.086}$, $M_\star = 1.211_{-0.046}^{+0.043} M_\odot$, and $R_\star = 1.360_{-0.053}^{+0.064} R_\odot$. The planet is a relatively high mass inflated gas giant with $M_\textrm{P} = 2.75_{-0.15}^{+0.16} M_\textrm{J}$, $R_\textrm{P} = 1.415_{-0.067}^{+0.084} R_\textrm{J}$, density $ρ_\textrm{P} = 1.20\pm0.18$ g cm$^{-3}$, surface gravity $\log{g_\textrm{P}} = 3.530_{-0.049}^{+0.042}$, and $T_\textrm{eq} = 2453_{-47}^{+55}$ K. The best-fitting linear ephemeris is $T_\textrm{C} = 2457247.24791\pm0.00019$ BJD$_{tdb}$ and $P = 0.9689951 \pm 0.0000024$ d. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with $P &lt; 1$ day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by HST, Spitzer, and eventually JWST. For example, as a hotter, higher mass analog of WASP-43b, KELT-16b may feature an atmospheric temperature-pressure inversion and day-to-night temperature swing extreme enough for TiO to rain out at the terminator. KELT-16b could also join WASP-43b in extending tests of the observed mass-metallicity relation of the Solar System gas giants to higher masses. KELT-16b currently orbits at a mere $\sim$ 1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few $\times 10^{5}$ years (for a stellar tidal quality factor of $Q_*' = 10^5$). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov oscillations played a role in driving KELT-16b inward to its current precarious orbit.
description: 16 pages, 18 Figures, 7 Tables, Accepted for publication in AJ