J/A+A/713/A57ivo://CDS.VizieR/J/A+A/713/A57CDSAnania R.Winter A.J.Vioque M.Rosotti G.P.Beccari G.Lodato G.,Malanga L.A.Piscarreta L.Somigliana A.Testi L.Toci C.2026-09-07T07:39:41Z2026-09-07T08:33:55ZCDS support team

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

cds-question@unistra.fraccretionob-starspre-main-sequence-starsyoung-stellar-objectsastrometryproper-motionsstellar-distanceultraviolet-astronomyOrion is the closest region hosting active star formation and young OBA stars. Accurately determining the far-ultraviolet (FUV) flux at its stellar population is essential to connect stellar and protoplanetary disc properties to the environment. We (1) accurately estimated the FUV flux and its distribution at a numerous stellar population of Orion by statistically accounting for the uncertainty in parallax measurements, and (2) investigated the relation between stellar accretion and external FUV radiation field by comparing observations and disc evolution models. We selected a large stellar population in Orion (within a 6 deg radius of the Orion Nebula Cluster core), assigned sub-cluster memberships, and used the two-dimensional sub-cluster geometry to infer three-dimensional separations from OBA stars and compute the FUV flux (and its uncertainty) at each stellar position. We studied the accretion luminosities (Lacc) inferred from Halpha emission in Gaia XP spectra of Orion sources and determined their detection fraction as a function of age and FUV flux. We compared the results with population synthesis models of viscous discs experiencing external photoevaporation. We provided a publicly available table of FUV fluxes at ~8600 stars in Orion. Most of this stellar population is weakly FUV-irradiated, <10^2^ G0, ~35% is intermediately irradiated, 10^2^-10^4^ G0, and only ~5% has FUV fluxes >10^4^ G0. Gaia-based Lacc decreases with age, and Halpha detection fraction declines more rapidly in regions with strong FUV fluxes (>10^2^ G0) than in regions exposed to weaker FUV fluxes (<10^2^ G0), broadly consistent with the model. This result may suggest that external photoevaporation efficiently depletes strongly FUV-irradiated accretion discs, but it is not sufficient to reliably confirm this conclusion. The tools we provided for accurately computing FUV fluxes at the Orion stellar population will be essential for targeting sources in future observations aimed at assessing the role of external photoevaporation on protoplanetary disc. Our study highlights the need for additional measurements of stellar and disc properties across the Orion population, covering the FUV flux range 1-10^5^ G0.2026A&A...713A..57Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/713/A57CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/713/A57https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/713/A57http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/713/A57https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/713/A57https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/713/A57http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/713/A57GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/713/A57/tableb1 (FUV flux at the position of Gaia DR3 stars members of Orion sub-clusters based on OPTICS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/713/A57/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/713/A57/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/713/A57/tableb1?GETtext/xml+votable180.050000true83.8188-5.671690.0055555555555555564/1339 1342 1428-1429 5/5350-5351 5362 5374 5701-5703 5710 5720-5721 5723-5724 5726-5727 5748-5749 5888 6/21306-21307 21393-21396 21398-21399 21417 21419 21422 21441-21443 21454-21455 21466 21491 21500 21502-21503 22184 22186-22187 22784-22785 22788 22790-22791 22797 22800-22801 22829 22831 22833-22838 22844 22846 22889 22891 22900-22902 22980-22981 23556 23560 23562-23563 23584 23592 23594 23680 23682https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/713/A57?format=asciiUVdefaultJ/A+A/713/A57/tableb1FUV flux at the position of Gaia DR3 stars members of Orion sub-clusters based on OPTICSrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadNameSimbad column added by the CDSmeta.idcharnullableIDSource raw number (n)meta.idintGaiaDR3Gaia DR3 identifier (source_id)meta.id;meta.mainSbClusterOrion sub-cluster name (cluster_name) (1)meta.id.parentcharRAJ2000Right ascension (J2000) (ra_deg)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (dec_deg)degpos.eq.dec;meta.mainpmRAProper motion RA (pm_ra_mas_yr)mas/yrpos.pm;pos.eq.radoublepmDEProper motion Dec (pm_dec_mas_yr)mas/yrpos.pm;pos.eq.decdoubleDistGeometric distance as 50th percentile (dist_pc)pcpos.distancedoubleb_DistGeometric distance as 16th percentile (dist_16_pc)pcpos.distancedoubleB_DistGeometric distance as 84th percentile (dist_84_pc)pcpos.distancedoubleFFUVFUV flux as 50th percentile in Habing unit G0 (fuv_flux_g0) (2)phot.flux;em.UVdoubleb_FFUVFUV flux as 16th percentile in Habing unit G0 (fuv_flux_16_g0) (2)phot.fluxdoubleB_FFUVFUV flux as 84th percentile in Habing unit G0 (fuv_flux_84_g0) (2)phot.fluxdoubleAnania25Display a new FUV flux catalogue for disc-hosting stars of Anania et al. 2025A&A...695A..74A, Cat. J/A+A/695/A74meta.ref.urlintnullableOrionDisplay the vizier orion ancilliary catalogsmeta.ref.urlintnullable