M2K. II. A TRIPLE-PLANET SYSTEM ORBITING HIP 57274

Journal Article · Fri Jan 20 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/745/1/21· OSTI ID:22011984

Fischer, Debra A; Giguere, Matthew J; Moriarty, John; Brewer, John; Spronck, Julien F. P.; Schwab, Christian; Szymkowiak, Andrew ^[1]; Gaidos, Eric ^[2]; Howard, Andrew W; Marcy, Geoffrey W ^[3]; Johnson, John A ^[4]; Wright, Jason T ^[5]; Valenti, Jeff A ^[6]; Piskunov, Nikolai ^[7]; Clubb, Kelsey I; Isaacson, Howard ^[8]; Apps, Kevin ^[9]; Lepine, Sebastien ^[10]; Mann, Andrew ^[11]

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1. Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
2. Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822 (United States)
3. Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States)
4. Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
5. Center for Exoplanets and Habitable Worlds, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16803 (United States)
6. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
7. Department of Astronomy and Space Physics, Uppsala University, Box 515, 751 20 Uppsala (Sweden)
8. Pufendorf Institute for Advanced Studies, Lund University, Lund (Sweden)
9. 75B Cheyne Walk, Surrey RH6 7LR (United Kingdom)
10. American Museum of Natural History, New York, NY 10023 (United States)
11. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

Doppler observations from Keck Observatory have revealed a triple-planet system orbiting the nearby K4V star, HIP 57274. The inner planet, HIP 57274b, is a super-Earth with Msin i = 11.6 M{sub Circled-Plus} (0.036 M{sub Jup}), an orbital period of 8.135 {+-} 0.004 days, and slightly eccentric orbit e = 0.19 {+-} 0.1. We calculate a transit probability of 6.5% for the inner planet. The second planet has Msin i = 0.4 M{sub Jup} with an orbital period of 32.0 {+-} 0.02 days in a nearly circular orbit (e = 0.05 {+-} 0.03). The third planet has Msin i = 0.53 M{sub Jup} with an orbital period of 432 {+-} 8 days (1.18 years) and an eccentricity e = 0.23 {+-} 0.03. This discovery adds to the number of super-Earth mass planets with M sin i < 12 M{sub Circled-Plus} that have been detected with Doppler surveys. We find that 56% {+-} 18% of super-Earths are members of multi-planet systems. This is certainly a lower limit because of observational detectability limits, yet significantly higher than the fraction of Jupiter mass exoplanets, 20% {+-} 8%, that are members of Doppler-detected, multi-planet systems.

• OSTI ID: 22011984
• Journal Information: Astrophysical Journal, Vol. 745, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
JUPITER PLANET
MASS
ORBITS
PROBABILITY
STARS