J/A+A/619/A1 55 Cnc radial velocities and photometry (Bourrier+, 2018) ================================================================================ The 55 Cancri system reassessed. Bourrier V., Dumusque X., Dorn C., Henry G.W., Astudillo-Defru N., Rey J., Benneke B., Hebrard G., Lovis C., Demory B.O., Moutou C., Ehrenreich D. =2018A&A...619A...1B (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ; Photometry Keywords: stars: individual: 55 Cnc - planets and satellites: fundamental parameters - planets and satellites: interiors - stars: activity - techniques: radial velocities - techniques: photometric Abstract: Orbiting a bright, nearby star the 55 Cnc system offers a rare opportunity to study a multiplanet system that has a wide range of planetary masses and orbital distances. Using two decades of photometry and spectroscopy data, we have measured the rotation of the host star and its solar-like magnetic cycle. Accounting for this cycle in our velocimetric analysis of the system allows us to revise the properties of the outermost giant planet and its four planetary companions. The innermost planet 55 Cnc e is an unusually close-in super-Earth, whose transits have allowed for detailed follow-up studies. Recent observations favor the presence of a substantial atmosphere yet its composition, and the nature of the planet, remain unknown. We combined our derived planet mass (Mp=8.0+/-0.3M_{Earth}_) with refined measurement of its optical radius derived from HST/STIS observations (Rp=1.88+/-0.03R_{Earth}_ over 530-750nm) to revise the density of 55 Cnc e (rho=6.7+/-0.4g/cm^3^). Based on these revised properties we have characterized possible interiors of 55 Cnc e using a generalized Bayesian model. We confirm that the planet is likely surrounded by a heavyweight atmosphere, contributing a few percents of the planet radius. While we cannot exclude the presence of a water layer underneath the atmosphere, this scenario is unlikely given the observations of the planet across the entire spectrum and its strong irradiation. Follow-up observations of the system in photometry and in spectroscopy over different time-scales are needed to further investigate the nature and origin of this iconic super-Earth. Description: Radial velocities of 55 Cnc from 7 different instruments HARPS, HARPN, LICK, KECK, HRS, SOPHIE, TULL. Photometry of 55 Cnc from the T8 automatic photoelectric telescope (APT) at Fairborn Observatory, relative to comparison stars C2 and C3. The subscript by indicates the observations are in the (b+y)/2 "passband". Objects: -------------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------------- 08 52 35.81 +28 19 51.0 55 Cnc = * rho01 Cnc -------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file apt55cnc.dat 35 2243 Photometry of 55 Cnc rv55cnc.dat 60 783 Radial velocities of 55 Cnc with S index -------------------------------------------------------------------------------- See also: J/ApJ/759/19 : Precise radial velocities of {rho}^1^ Cancri (Endl+, 2012) J/ApJ/792/L31 : HARPS & HARPS-N 55 Cnc radial velocities (Lopez-Morales+, 2014) J/AJ/153/208 : LCES HIRES/Keck radial velocity Exoplanet Survey (Butler+ 2017) Byte-by-byte Description of file: apt55cnc.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 F10.4 d RJD Reduced Julian date (JD-2400000) 13- 18 F6.4 mag (P-C2)by Differential (b+y)/2 magnitude between 55 Cnc and star C2 21- 27 F7.4 mag (P-C3)by Differential (b+y)/2 magnitude between 55 Cnc and star C2 30- 35 F6.4 mag (C3-C2)by Differential (b+y)/2 magnitude between stars C3 and C2 -------------------------------------------------------------------------------- Byte-by-byte Description of file: rv55cnc.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 F13.7 d RJD Reduced Julian date (JD-2400000) 15- 26 F12.5 m/s RV Radial velocity 28- 35 F8.5 m/s e_RV Radial velocity photon plus instrument error 37- 44 F8.6 --- Smw S Mount Wilson index 46- 53 F8.6 --- e_Smw S Mount Wilson index error 55- 60 A6 --- Inst Name of instrument -------------------------------------------------------------------------------- Acknowledgements: Vincent Bourrier, Vincent.Bourrier(at)unige.ch Xavier Dumusque, Xavier.Dumusque(at)unige.ch [University of Geneva, Switzerland] Gregory W. Henry [Tennessee State University, USA] References: Endl et al., 2012ApJ...759...19E, Cat. J/ApJ/759/19 Fischer et al., 2008ApJ...675..790F Butler et al., 2017AJ....153..208B, Cat. J/AJ/153/208 Lopez-Morales et al., 2014ApJ...792L..31L, Cat. J/ApJ/792/L31 ================================================================================ (End) Vincent Bourrier [Geneva University], Patricia Vannier [CDS] 26-Jul-2018