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/KELT-16. A global analysis of the system shows KELT-16 to be an F7V star with K and . The planet is a relatively high-mass inflated gas giant with density g cm-3, surface gravity , and K. The best-fitting linear ephemeris is and day. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with P < 1 day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by the Hubble Space Telescope, Spitzer, and eventually the James Webb Space Telescope. 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 ∼1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few ×105 years (for a stellar tidal quality factor of ). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov (KL) oscillations played a role in driving KELT-16b inward to its current precarious orbit.
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Oberst, T., Rodriguez, J., Colón, K., Angerhausen, D., Bieryla, A., Ngo, H., Stevens, D., Stassun, K., Gaudi, B., Pepper, J., Penev, K., Mawet, D., Latham, D., Heintz, T., Osei, B., Collins, K., Kielkopf, J., Visgaitis, T., Reed, P., Escamilla, A., Yazdi, S., McLeod, K., Lunsford, L., Spencer, M., Joner, M., Gregorio, J., Gaillard, C., Matt, K., Dumont, M., Stephens, D., Cohen, D., Jensen, E., & Novati, S. (2017). KELT-16b: A Highly Irradiated, Ultra-short Period Hot Jupiter Nearing Tidal Disruption. Astronomical Journal, 153 (3) https://doi.org/10.3847/1538-3881/153/3/97