55 Cancri: stellar astrophysical parameters, a planet in the habitable zone, and implications for the radius of a transiting super-earth

von Braun, Kaspar and Boyajian, Tabetha S. and ten Brummelaar, Theo A. and Kane, Stephen R. and van Belle, Gerard T. and Ciardi, David R. and Raymond, Sean N. and Lopez-Morales, Mercedes and McAlister, Harold A. and Schaefer, Gail and Ridgway, Stephen T. and Sturmann, Laszlo and Sturmann, Judit and White, Russel and Turner, Nils H. and Farrington, Chris and Goldfinger, P. J. (2011) 55 Cancri: stellar astrophysical parameters, a planet in the habitable zone, and implications for the radius of a transiting super-earth. The Astrophysical Journal, 740 (1). pp. 49-54. ISSN 0004-637X

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Abstract

The bright star 55 Cancri is known to host five planets, including a transiting super-Earth. The study presented here yields directly determined values for 55Cnc's stellar astrophysical parameters based on improved interferometry: R = 0.943 ± 0.010 R ∞, T EFF = 5196 ± 24K. We use isochrone fitting to determine 55Cnc's age to be 10.2 ± 2.5Gyr, implying a stellar mass of 0.905 ± 0.015 M ∞. Our analysis of the location and extent of the system's habitable zone (HZ; 0.67-1.32AU) shows that planet f, with period 260days and Msin i = 0.155 M Jupiter, spends the majority of the duration of its elliptical orbit in the circumstellar HZ. Though planet f is too massive to harbor liquid water on any planetary surface, we elaborate on the potential of alternative low-mass objects in planet f's vicinity: a large moon and a low-mass planet on a dynamically stable orbit within the HZ. Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55Cnc e (∼2.05 ±0.15 R ⊕), which, depending on the planetary mass assumed, implies a bulk density of 0.76 ρ⊕ or 1.07 ρ⊕.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: No Faculty
Date Deposited: 08 Jun 2017 23:51
Last Modified: 27 Jun 2017 04:47
Uncontrolled Keywords: infrared stars; planetary systems; fundamental parameters; stars: stars; 55 Cnc; late-type stars; interferometric techniques
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1088/0004-637X/740/1/49
URI: http://eprints.usq.edu.au/id/eprint/32162

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