Access to Astronomical Catalogues

← Click to display the menu
J/A+A/615/A117     55 CnC geocoronal emission lines template   (Bourrier+, 2018)

High-energy environment of super-Earth 55 Cnc e. I: Far-UV chromospheric variability as a possible tracer of planet-induced coronal rain Bourrier V., Ehrenreich D., Lecavelier des Etangs A., Louden T., Wheatley P.J., Wyttenbach A., Vidal-Madjar A., Lavie B., Pepe F., Udry S. <Astron. Astrophys. 615, A117 (2018)> =2018A&A...615A.117B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Exoplanets ; Spectroscopy Keywords: methods: data analysis - techniques: spectroscopic - planets and satellites: individual: 55 Cnc e - stars: chromospheres - ultraviolet: stars Abstract: The high-energy X-ray to ultraviolet (XUV) irradiation of close-in planets by their host star influences their evolution and might be responsible for the existence of a population of ultra-short period planets eroded to their bare core. In orbit around a bright, nearby G-type star, the super-Earth 55 Cnc e offers the possibility to address these issues through transit observations at UV wavelengths. We used the Hubble Space Telescope to observe the transit in the far-ultraviolet (FUV) over three epochs in April 2016, January 2017, and February 2017. Together, these observations cover nearly half of the orbital trajectory in between the two quadratures, and reveal significant short- and long-term variability in 55 Cnc chromospheric emission lines. In the last two epochs, we detected a larger flux in the CIII, SiIII, and SiIV lines after the planet passed the approaching quadrature, followed by a flux decrease in the SiIV doublet. In the second epoch these variations are contemporaneous with flux decreases in the SiII and CII doublet. All epochs show flux decreases in the NV doublet as well, albeit at different orbital phases. These flux decreases are consistent with absorption from optically thin clouds of gas, are mostly localized at low and redshifted radial velocities in the star rest frame, and occur preferentially before and during the planet transit. These three points make it unlikely that the variations are purely stellar in origin, yet we show that the occulting material is also unlikely to originate from the planet. We thus tentatively propose that the motion of 55 Cnc e at the fringes of the stellar corona leads to the formation of a cool coronal rain. The inhomogeneity and temporal evolution of the stellar corona would be responsible for the differences between the three visits. Additional variations are detected in the CII doublet in the first epoch and in the OI triplet in all epochs with a different behavior that points toward intrinsic stellar variability. Further observations at FUV wavelengths are required to disentangle definitively between star-planet interactions in the 55 Cnc system and the activity of the star. Description: We provide four tables that contain observational templates for four geocoronal emission lines (one table per line, indicated in the file name). We caution that the lines are not centered on their rest wavelengths and have an arbitrary flux scaling. The user must fit the position and amplitude of the templates according to their observations, as these properties are specific to a given observation with the HST. The templates can be seen in the paper in the following figures: atoi1305.dat: OI line (rest wavelength 1304.8576 A) in Fig. 4 atoi1306.dat: OI line (rest wavelength 1306.0286 A) in Fig. 4 atoi1302.dat: OI line (rest wavelength 1302.1685 A) in Fig. 5 athi1216.dat: HI line (rest wavelength 1215.6702 A) in Fig. 6 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 atoi1305.dat 51 273 OI line (rest wavelength 1304.8576Å) in Fig. 4 atoi1306.dat 51 272 OI line (rest wavelength 1306.0286Å) in Fig. 4 atoi1302.dat 51 271 OI line (rest wavelength 1302.1685Å) in Fig. 5 athi1216.dat 51 272 HI line (rest wavelength 1215.6702Å) in Fig. 6
See also: J/A+A/533/A114 : Transit of super-Earth 55 Cnc e (Demory+, 2011) J/A+A/539/A28 : New transit photometry for super-Earth 55 Cnc e (Gillon+, 2012 J/A+A/545/A97 : 0.8-6µm calibrated spectrum of 55 Cnc (Crossfield, 2012) J/ApJ/778/132 : C and O abundances in 55 Cnc (Teske+, 2013) J/ApJ/792/L31 : 55 Cnc HARPS & HARPS-N radial velocities (Lopez-Morales+ 2014) Byte-by-byte Description of file: at*.dat
Bytes Format Units Label Explanations
1- 11 F11.6 0.1nm lambda Wavelength, in angstroms 15- 31 E17.10 10-2W/m2/nm Flux Flux of a given geocoronal emission line, in erg/cm2/Å/s 36- 51 E16.10 10-2W/m2/nm e_Flux Flux associated error, in erg/cm2/Å/s
Acknowledgements: Vincent Bourrier, Vincent.Bourrier(at)unige.ch
(End) Patricia Vannier [CDS] 26-Mar-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© Université de Strasbourg/CNRS

    • Contact