J/A+A/690/A159ivo://CDS.VizieR/J/A+A/690/A159doi:10.26093/cds/vizier.36900159CDSPatel J.A.Brandeker A.Kitzmann D.Petit dit de la Roche D.J.M.,Bello-Arufe A.Heng K.Meier Valdes E.Persson C.M.Zhang M.,Demory B.-O.Bourrier V.Deline A.Ehrenreich D.Fridlund M.Hu R.,Lendl M.Oza A.V.Alibert Y.Hooton M.J.2025-02-24T20:01:32Z2024-10-08T10:49:17ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frmultiple-starsexoplanetsphotometryinfrared-astronomyspectroscopyThe nature of the close-in rocky planet 55 Cnc e is puzzling despite having been observed extensively. Its optical and infrared occultation depths show temporal variability, in addition to a phase curve variability observed in the optical. We wish to explore the possibility that the variability originates from the planet being in a 3:2 spin-orbit resonance, thus showing different sides during occultations. We proposed and were awarded Cycle 1 time at the James Webb Space Telescope (JWST) to test this hypothesis. JWST/NIRCam (Near Infrared Camera) observed five occultations (secondary eclipses), of which four were observed within a week, of the planet simultaneously at 2.1 and 4.5um. While the former gives band-integrated photometry, the latter provides a spectrum between 3.9-5.0um. We find that the occultation depths in both bandpasses are highly variable and change between a non-detection (-5+/-6ppm and 7+/-9ppm) to 96+/-8ppm and 119^+34^_-19_ppm at 2.1um and 4.5um, respectively. Interestingly, the variations in both bandpasses are not correlated and do not support the 3:2 spin-orbit resonance explanation. The measured brightness temperature at 4.5um varies between 873-2256K and is lower than the expected dayside temperature of bare rock with no heat re-distribution (2500K) which is indicative of an atmosphere. Our atmospheric retrieval analysis of occultation depth spectra at 4.5um finds that different visits statistically favour various atmospheric scenarios including a thin outgassed CO/CO2 atmosphere and a silicate rock vapour atmosphere. Some visits even support a flat line model. The observed variability could be explained by stochastic outgassing of CO/CO2, which is also hinted by retrievals. Alternatively, the variability, observed at both 2.1 and 4.5um, could be the result of a circumstellar patchy dust torus generated by volcanism on the planet.2024A&A...690A.159Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A159CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/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 : 0.8-6{mu}m calibrated spectrum of 55 Cnc (Crossfield, 2012)J/ApJ/778/132 : C and O abundances in 55 Cnc (Teske+, 2013)J/ApJ/792/L31 : HARPS & HARPS-N 55 Cnc radial velocities (Lopez-Morales+ 2014)J/A+A/615/A117 : 55 Cnc geocoronal emission lines template (Bourrier+, 2018)J/A+A/619/A1 : 55 Cnc radial velocities and photometry (Bourrier+, 2018)J/A+A/653/A173 : CHEOPS 55 Cnc light curve (Morris+, 2021)J/A+A/677/A112 : CHEOPS observations of 55 Cnc e (Meier Valdes+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A159https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A159http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A159https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A159https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A159http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A159GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/A+A/690/A159/tablee1Raw photometric (for 2.1um short-wave SW channel) and white-light (for 4.5um long-wave LW channel) light curves for all visits of 55 Cnc e observed by NIRCam/JWST (Fig. 1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTime (BJD)dtime.epochdoubleindexedFluxNormalised raw fluxphot.flux;arith.ratiodoublee_Flux1-sigma uncertainty in fluxstat.error;phot.fluxdoubleVisitVisit (V1-V5) (Gi)meta.id;obscharChannel[LW SW] Channel (2)meta.id;instrcharJ/A+A/690/A159/tablee2Occultation depths spectra for all visits observed by NIRCam/JWST (Fig. 3)VisitVisit (V1-V5) (G1)meta.id;obscharMethodReduction method (Eureka, HANSOLO, SPARTA or stark)stat.fit;obs.paramcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[3.86/4.98] Wavelengthumem.wldoubleFpOccultation depthphot.flux.density;arith.diffdoubleE_FpUpper 68 credible interval of Fpstat.error;stat.maxdoublee_FpLower 68 credible interval of Fpstat.errordouble