55 Cancri: Stellar Astrophysical Parameters, a Planet in the...
- ️Invalid Date
Authors:Kaspar von Braun (1), Tabetha S. Boyajian (2,3), Theo A. ten Brummelaar (6), Stephen R. Kane (1), Gerard T. van Belle (4), David R. Ciardi (1), Sean N. Raymond (9,10), Mercedes Lopez-Morales (5,8), Harold A. McAlister (2), Gail Schaefer (6), Stephen T. Ridgway (7), Laszlo Sturmann (6), Judit Sturmann (6), Russel White (2), Nils H. Turner (6), Chris Farrington (6), P.J. Goldfinger (6) ((1) NASA Exoplanet Science Institute / Caltech, (2) Georgia State U., (3) Hubble Fellow, (4) ESO, (5) CSIC-IEEC, (6) CHARA, (7) NOAO, (8) Carnegie/DTM, (9) Universite de Bordeaux, (10) Laboratoire d'Astrophysique de Bordeaux)
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 55 Cnc's stellar astrophysical parameters based on improved interferometry: $R=0.943 \pm 0.010 R_{\odot}$, $T_{\rm EFF} = 5196 \pm 24$ K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 $\pm$ 2.5 Gyr, implying a stellar mass of $0.905 \pm 0.015 M_{\odot}$. Our analysis of the location and extent of the system's habitable zone (0.67--1.32 AU) shows that planet f, with period $\sim$ 260 days and $M \sin i = 0.155 M_{Jupiter}$, spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone. 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 habitable zone. 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 ($\sim 2.05 \pm 0.15 R_{\earth}$), which, depending on the planetary mass assumed, implies a bulk density of 0.76 $\rho_{\earth}$ or 1.07 $\rho_{\earth}$.
Submission history
From: Kaspar von Braun [view email]
[v1]
Mon, 6 Jun 2011 19:00:41 UTC (218 KB)
[v2]
Fri, 22 Jul 2011 23:59:32 UTC (329 KB)