55 CANCRI: STELLAR ASTROPHYSICAL PARAMETERS, A PLANET IN THE HABITABLE ZONE, AND IMPLICATIONS FOR THE RADIUS OF A TRANSITING SUPER-EARTH

Journal Article · Mon Oct 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/740/1/49; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587411

Von Braun, Kaspar; Kane, Stephen R; Ciardi, David R ^[1]; Tabetha, S Boyajian; McAlister, Harold A; White, Russel ^[2]; Ten Brummelaar, Theo A; Schaefer, Gail; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H; Farrington, Chris; Goldfinger, P J ^[3]; Van Belle, Gerard T ^[4]; Raymond, Sean N ^[5]; Lopez-Morales, Mercedes ^[6]

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1. NASA Exoplanet Science Institute, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States)
2. Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P. O. Box 4106, Atlanta, GA 30302-4106 (United States)
3. The CHARA Array, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States)
4. European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany)
5. Universite de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, 2 rue de l'Observatoire, BP 89, F-33271 Floirac Cedex (France)
6. Institut de Ciencies de L'Espai (CSIC-IEEC), Campus UAB, Facultat Ciencies, Torre C5 parell 2, 08193 Bellaterra, Barcelona (Spain)

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 55 Cnc's stellar astrophysical parameters based on improved interferometry: R = 0.943 {+-} 0.010 R{sub sun}, T{sub EFF} = 5196 {+-} 24 K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 {+-} 2.5 Gyr, implying a stellar mass of 0.905 {+-} 0.015 M{sub sun}. Our analysis of the location and extent of the system's habitable zone (HZ; 0.67-1.32 AU) shows that planet f, with period {approx}260 days and Msin i = 0.155 M{sub 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 55 Cnc e ({approx}2.05 {+-} 0.15 R{sub +}), which, depending on the planetary mass assumed, implies a bulk density of 0.76 {rho}{sub +} or 1.07 {rho}{sub +}.

• OSTI ID: 21587411
• Journal Information: Astrophysical Journal, Vol. 740, Issue 1; Other Information: DOI: 10.1088/0004-637X/740/1/49; 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
ASTROPHYSICS
INTERFEROMETRY
PLANETS
STARS
PHYSICS