The Kepler-454 system: A small, not-rocky inner planet, a Jovian World, and a distant companion

Journal Article · Sun Jan 10 00:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/816/2/95· OSTI ID:22882300

Gettel, Sara; Charbonneau, David; Dressing, Courtney D.; Buchhave, Lars A.; Dumusque, Xavier; Vanderburg, Andrew; Latham, David W. ^[1]; Bonomo, Aldo S. ^[2]; Malavolta, Luca ^[3]; Pepe, Francesco; Udry, Stéphane ^[4]; Cameron, Andrew Collier ^[5]; Marcy, Geoffrey W.; Isaacson, Howard ^[6]; Howard, Andrew W. ^[7]; Davies, Guy R. ^[8]; Aguirre, Victor Silva; Kjeldsen, Hans; Bedding, Timothy R. ^[9]; Lopez, Eric ^[10] ; others, and

---

1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. INAF—Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy)
3. Dipartimento di Fisica e Astronomia “Galileo Galilei,” Universita’di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy)
4. Observatoire Astronomique de l’Université de Genève, 51 ch. des Maillettes, 1290 Versoix (Switzerland)
5. SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews Fife, KY16 9SS (United Kingdom)
6. University of California, Berkeley, CA, 94720 (United States)
7. Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
8. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)
9. Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)
10. SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH93HJ (United Kingdom)

Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin i < 2.4 km s{sup −1}. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be 1.028{sub −0.03}{sup +0.04}M{sub ⊙}, the radius to be 1.066 ± 0.012 R{sub ⊙}, and the age to be 5.25{sub −1.39}{sup +1.41} Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R{sub ⊕}. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M{sub ⊕}. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 M{sub J} in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 M{sub J}. The 12 exoplanets with radii <2.7 R{sub ⊕} and precise mass measurements appear to fall into two populations, with those <1.6 R{sub ⊕} following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm{sup −3}, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.

• OSTI ID: 22882300
• Journal Information: Astrophysical Journal, Vol. 816, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
MASS
METALLICITY
ORBITS
PLANETS
RADIAL VELOCITY
SATELLITES
SPECTROSCOPY
STARS