论文信息 - KELT-6b: A P ∼ 7.9 DAY HOT SATURN TRANSITING A METAL-POOR STAR WITH A LONG-PERIOD COMPANION - 字舞流文

KELT-6b: A P ∼ 7.9 DAY 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 ± 43 K,_log g_* =4.07_(-0.07)^(+0.04), and [Fe/H] = –0.28 ± 0.04, with an inferred mass M_* = 1.09 ± 0.04 M_☉ and radius R_* =1.58_(-0.09)^(+0.16) ,R_☉. The planetary companion has mass M_P = 0.43 ± 0.05 M_(Jup), radius R_p =1.19_(-0.08)^(+0.13),R_(Jup), surface gravity g_p = 2.86_(-0.08)^(+0.06), and density P_p = 0.31_(-0.08)^(+0.07), cm^(-3). The planet is on an orbit with semimajor axis ɑ = 0.079 ± 0.001 AU and eccentricity e = 0.22_(-0.10)^(+0.12), which is roughly consistent with circular, and has ephemeris of T_c(BJD_(TDB)) = 2456347.79679 ± 0.00036 and P = 7.845631 ± 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by ~4}-7}. KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images.

Keivan G. Stassun | Andrew Gould | B. Scott Gaudi | Debra A. Fischer | Jason D. Eastman | John Asher Johnson | Darren L. DePoy | Robert J. Siverd | Thomas G. Beatty | Eric L. N. Jensen | Justin R. Crepp | John F. Kielkopf | Richard W. Pogge | S. N. Mellon | Rachel A. Street | Sasha Hinkley | Patricia Trueblood | Benjamin J. Fulton | Ryan J. Oelkers | Andrew W. Howard | David W. Latham | Phillip Cargile | Joshua Pepper | Perry Berlind | Allyson Bieryla | Joao Gregorio | Kim K. McLeod | Thomas E. Oberst | Karen A. Collins | Mark Trueblood | Michael L. Calkins | Gilbert A. Esquerdo | Lars A. Buchhave | M. Penny | C. Mack | Qingqing Mao | J. Pepper | K. Stassun | J. Marshall | P. Cargile | B. Gaudi | A. Gould | R. Street | D. Depoy | P. Berlind | M. Calkins | S. Hinkley | J. Crepp | J. Eastman | R. Pogge | L. Buchhave | D. Latham | A. Howard | D. Fischer | J. Johnson | B. Fulton | A. Bieryla | G. Esquerdo | R. Stefanik | K. Collins | T. Beatty | R. Siverd | M. Trueblood | J. Kielkopf | R. Oelkers | T. Oberst | K. Penev | E. Jensen | J. Gregorio | M. Manner | K. McLeod | P. Trueblood | Kaloyan Penev | Qingqing Mao | Jennifer L. Marshall | Mark Manner | Claude E. Mack | Ryan L. Avril | Samuel N. Mellon | Matthew T. Penny | Robert P. Stefanik | Alexander J. W. Richert | R. Avril | C. E. Mack | J. Marshall | J. Johnson | S. Mellon | K. Mcleod

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