J/A+A/706/A349ivo://CDS.VizieR/J/A+A/706/A349doi:10.26093/cds/vizier/bc-p2/ldejCDSDamonte A.Pillitteri I.Maggio A.Garcia Munoz A.Micela G.2026-04-02T20:03:03Z2026-02-25T09:29:35ZCDS support team

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

cds-question@unistra.frx-ray-sourcesspectroscopyStellar soft X-ray ([1, 100]{AA}) and Extreme Ultraviolet (also EUV, [100, 920]{AA}; jointly, XUV) radiation affects the evolution and chemistry of exoplanet atmospheres. It is however uncertain to what extent the radiation's short-term variability contributes to these effects. The answer might indeed depend on the atmospheric composition in ways that remain largely unexplored. We are interested in what this variability might imply for planets around M dwarf stars, and focus on Proxima Centauri (Prox Cen) for three reasons, namely: it is an active M dwarf with high levels of variability; it hosts a likely terrestrial exoplanet within its habitable zone (HZ) that will be a prime target for future direct imaging; and its proximity has led to extensive observations, yielding some of the best available X-ray data. We set out to produce time-resolved XUV spectra of Prox Cen that will serve as input to atmospheric models, and to characterize the intrinsic variability of the star and its uncertainties in the inferred spectra. We analyzed the entire dataset of archival XMM-Newton observations for Prox Cen. To derive the time- resolved X-ray spectra, we implemented a new pile-up correction, a new adaptive time-binning algorithm, and a time-dependent plasma model selection. The estimated EUV spectrum is based on a published template, that we scale with proposed relationships between X-ray and EUV fluxes. We produced spectra of Prox Cen from 1 to 920{AA} over ~260ks of observations with unprecedented time resolution. The instantaneous X-ray flux of Prox Cen varies between about 20 times and one-fifth of the average value over the available baseline, with significant differences between wavelengths. We further quantify how variability affects the estimated average flux when a limited number of snapshots (each typically of 30 ks exposure) are available, as is common in X-ray surveys. Future investigations of the atmospheres of Prox Cen b should fold in the time variability and uncertainties described here.2026A&A...706A.349Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/706/A349CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/534/A133 : Proxima Cen chromospheric emission lines (Fuhrmeister+, 2011)J/A+A/603/A58 : Full spectrum of Proxima Centauri (Ribas+, 2017)J/A+A/626/A111 : Proxima Cen flare activity temporal changes (Pavlenko+, 2019)J/A+A/638/A120 : SPHERE maps around Proxima Cen (Gratton+, 2020)J/A+A/639/A77 : Proxima Cen RV, FWHM and fluxes (Suarez Mascareno+, 2020)J/A+A/658/A115 : Proxima Cen ESPRESSO RV and FWHM (Faria+, 2022)J/A+A/666/A196 : Proxima telluric-corrected ESPRESSO RV (Allart+, 2022)J/A+A/700/A11 : Proxima spectroscopy and photometry (Suarez Mascareno+, 2025)J/A+A/700/A177 : Proxima + Gl581 activity-sensitive linesJ/AJ/153/93 : MOST photometry of Proxima (Kipping+, 2017)J/AJ/155/12 : Photometry of Proxima Centauri observed by BSST (Liu+, 2018)J/AJ/157/226 : Photometry of Proxima Centauri from 2006 to 2017https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/706/A349https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/706/A349http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/706/A349https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/706/A349https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/706/A349http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/706/A349GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-raydefaultJ/A+A/706/A349/listList of fits filesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintNzNumber of tablesmeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitschar