J/AJ/170/293ivo://CDS.VizieR/J/AJ/170/293CDSPeacock S.Wilson D.J.Richey-Yowell T.Tuchow N.W.France K.,Caballero J.A.Spinelli R.Corrales L.Zelakiewicz A.S.Redfield S.,Rockcliffe K.Youngblood A.Froning C.S.Duvvuri G.M.Binder B.A.,Hinkel N.R.Mamajek E.E.2026-08-25T08:54:15Z2026-08-21T12:40:27ZCDS support team

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

cds-question@unistra.frx-ray-sourcesphotometryspectroscopyultraviolet-astronomyexoplanetsstellar-distancespace-observatoriesobservational-astronomymorgan-keenan-classificationmetallicityh-i-line-emissionWe assess archival high-energy data for key stars on the Habitable Worlds Observatory (HWO) Target Stars and Systems 2025 list, as stellar radiation is critical to shaping and interpreting planetary atmospheres. Using a sample of 98 nearby stars (HWO Tier 1 targets), we compile and evaluate X-ray and ultraviolet (UV) data from archival eROSITA, Chandra, XMM-Newton, ROentgen SATellite, Extreme-Ultraviolet Explorer, Swift, Far Ultraviolet Spectroscopic Explorer, International Ultraviolet Explorer (IUE), Galaxy Evolution Explorer, and Hubble Space Telescope (HST). We examine spectral and temporal coverage, assess data quality, and identify major gaps. UV data are moderately available, with most coverage coming from near-UV spectra from IUE. Far fewer stars have far-UV spectra, especially from HST. In the X-ray regime, some stars have high-quality spectra, while others are limited to shallow detections or broadband photometry. A small fraction of the sample has both X-ray and UV spectra of sufficient quality to support full spectral energy distribution modeling. Truly comprehensive coverage across X-ray, extreme-UV, and both UV bands remains extremely rare. Most data sets are single-epoch, limiting assessments of variability and flares-key factors in atmospheric photochemistry and escape. Moreover, the lack of simultaneous or contemporaneous observations across bands adds further uncertainty. Our findings underscore the need for new space-based missions and coordinated multiwavelength campaigns, ideally with overlapping coverage, to improve stellar characterization for HWO. As several key observatories age and face potential decommissioning, there is a narrow window of opportunity to secure these critical data. Investing in this effort now will directly support the science goals of HWO and enhance future studies of planetary habitability.2025AJ....170..293Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/170/293CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)II/203A : Second Extreme Ultra-Violet Explorer Catalog (2EUVE, 1997)III/135A : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989)IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)VI/110 : Final Merged Log of IUE Observations (NASA-ESA, 2000)IX/10A : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)IX/35 : Second EUVE Catalogues (Bowyer+, 1996-99)IX/69 : XMM-Newton Serendipitous Source Catalogue 4XMM-DR13 (Webb+, 2023)IX/70 : Chandra Source Catalog Release 2 (CSC 2.1) (Evans+, 2024)J/ApJ/657/1046 : Synthetic Mid-UV spectr. indices of stars (Chavez+, 2007)J/ApJS/187/149 : StarCAT: STIS UV echelle spectra of stars (Ayres, 2010)J/ApJ/761/166 : Terrestrial exoplanet atmospheres. I. (Hu+, 2012)J/A+A/588/A103 : Second ROSAT all-sky survey (2RXS) source cat. (Boller+, 2016)J/MNRAS/489/5046 : GALEX absolute calib. based on white dwarfs (Wall+, 2019)J/A+A/664/A105 : Stellar content of the ROSAT all-sky survey (Freund+, 2022)J/AJ/163/67 : 5-55000{AA} spectrum of TOI 560 (Zhang+, 2022)J/ApJS/275/1 : X-ray obs. of potential host star's HZ (Binder+, 2024)J/ApJS/272/30 : Habitable Worlds Observatory (HWO): 164 targets (Harada+, 2024)J/A+A/682/A34 : SRG/eROSITA all-sky survey catalogs (eRASS1) (Merloni+, 2024)J/AJ/167/139 : HPIC catalog & potential contaminants from Gaia (Tuchow+, 2024)J/A+A/693/A285 : Spectr. Energy Distribution of 100 stars (Sanz-Forcada+, 2025)J/PASP/137/J4402 : HWO Target Stars & Systems 2025 list (TSS25) (Tuchow+, 2025)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/170/293https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/170/293http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/170/293https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/170/293https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/170/293http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/170/293GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/170/293/targets (List of ExEP Tiers A and B stars (added by CDS))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/293/targets?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/293/targets?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/293/targets?GETtext/xml+votable180.050000true173.6228603-32.83133970.005555555555555556Cone search capability for table J/AJ/170/293/table2 (*HWO TSS high energy emission data catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/293/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/293/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/293/table2?GETtext/xml+votable180.050000true93.7119813219.15644740.005555555555555556Cone search capability for table J/AJ/170/293/table4 (*LISM column densities for TSS25 Tier 1 stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/293/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/293/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/293/table4?GETtext/xml+votable180.050000true173.6228596-32.831338990.0055555555555555566/684 1341 1603 1875 2472 3020 3036 3102 3118 3639 3932 4438 4854 5009 5074 5304 5420 5522 5670 5836 5853 6066 6766 6926 6941 7595 7763 8109 8145 8476 8790 8985 9125 9403 9476 9835 10375 10812 10899 11403 11633 11806 12592 13301 14180 14278 14419 14459 15356 15962 16069 16412 17171 17425 17576 18139 19323 19585 19912 20328 21060 21177 21484 22040 22708 22818 23140 23190 23230 23369 23675 23974 24028 24160 24212 24713 24793 24924 25056 26975 27973 28605 28664 28696 29196 29239 29255 30576 30665 30878 30965 31433 31478 31751 32757 32848 33211 33281 33340 33552 33717 33849 34446 34817 34896 34905 35064 35351 35948 36145 36365 36446 36664 36693 36697 36983 37408 37595 38064 38238 39284 39500 39744 40078 40242 40692 40932 41763 41941 42248 42253 42285 42700 42760 43074 43639 44284 44557 45485 45535 45564 45668-45669 46113 46566 46640 46776 46925 46982 47101 47137 47589 48334 48355 486523.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/170/293?format=asciiX-rayUVOpticalRadiodefaultJ/AJ/170/293/targetsList of ExEP Tiers A and B stars (added by CDS)HDHenry Draper Catalog (III/135A) IDmeta.id;meta.maincharprimaryTICTESS Input Catalog (IV/39) IDmeta.idcharExEPExEP tier classification (A or B) (1)meta.code.classcharTab3Link to modeled NUV fluxes (Table 3)meta.ref.urlcharTab4Link to column densities (Table 4)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNobsNumber of observations in the HWO TSS high energy emission data catalog (link to Table 2)meta.numberintnullableTSS25Display the HWO Target Stars and Systems 2025 list (Tuchow+2025, J/PASP/137/J4402) catalog datameta.ref.urlcharH24Display the Habitable Worlds Observatory (Harada+2024, J/ApJS/272/30) catalog datameta.ref.urlchar_RAPosition from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPosition from Simbad (declination part)degpos.eq.dec;meta.mainJ/AJ/170/293/table2*HWO TSS high energy emission data catalogHDHenry Draper Catalog (III/135A) IDmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Input Catalog (IV/39) IDmeta.idcharRAJ2000Right ascension at epoch J2000 (ICRS)degpos.eq.ra;meta.mainDEJ2000Declination at epoch J2000 (ICRS)degpos.eq.dec;meta.mainVmag[0.01/7.52] Apparent Johnson V magnitudemagphot.mag;em.opt.VfloatDist[1.34/21.78] Distancepcpos.distancedoubleSpTypeSpectral typesrc.spTypecharTeff[3469/6782] Effective temperatureKphys.temperature.effectiveintExEPExEP tier classification (A or B)meta.code.classcharObsObservatory used for observation (1)meta.id;instr.obstycharInstInstrument used for observation (2)meta.id;instrcharModeObserving modeinstr.setupcharTypeObservation type (3)meta.code;obscharBandGeneral wavelength band (4)instr.bandpasscharWaveWavelength coverage of observation in Angstromsinstr.bandwidthcharQualityDescription of data qualitymeta.notecharFlag[0/2] Quality flag (5)meta.code.qualintURLURL for where to access the datameta.ref.urlcharJ/AJ/170/293/table3Modeled NUV fluxes for TSS25 Tier 1 stars[F2000-2500][-16.25/-10.17] Log of flux in 2000-2500 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloat[F2500-3000][-14.26/-9.38] Log of flux in 2500-3000 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloat[F3000-3500][-12.9/-8.79] Log of flux in 3000-3500 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloat[F3500-4000][-12.45/-8.7] Log of flux in 3500-4000 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloat[F4000-4500][-11.8/-8.43] Log of flux in 4000-4500 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloatTierAB*=The target is tier A or B and is part of the subset presented in Table 2 (link to all data for this target)meta.ref.urlcharSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharTeff[3469/6962] Effective temperature (1)Kphys.temperature.effectiveintlogg[3.61/4.78] Log of surface gravity (1)phys.gravityfloat[Fe/H][-1.33/0.38] Metallicity (1)phys.abund.FefloatDist[1.35/23.29] Distance (1)pcpos.distancefloatRad[0.4/2.4] Radius (1)solRadphys.size.radiusfloat[FNUV][-15.27/-9.96] Log of GALEX NUV flux; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UV.200-300nmfloat[F2500-4000][-12.8/-8.88] Log of flux in 2500-4000 Angstrom band; erg/s/cm2 (2)log(mW.cm**-2)phot.flux;em.UVfloatTSS25Display the HWO Target Stars and Systems 2025 list (Tuchow+2025, J/PASP/137/J4402) catalog datameta.ref.urlcharH24Display the Habitable Worlds Observatory (Harada+2024, J/ApJS/272/30) catalog datameta.ref.urlcharJ/AJ/170/293/table4*LISM column densities for TSS25 Tier 1 starsTierAB*=The target is tier A or B and is part of the subset presented in Table 2 (link to all data for this target)meta.ref.urlcharSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharf_NameFlag on Name (1)meta.codecharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainDist[1.35/23.29] Distancepcpos.distancefloatlogNHI-e[17.61/18.8] Estimated column density (2)log(cm**-2)phys.columnDensityfloate_logNHI-e[0.22/0.36] Uncertainty in logNHI-elog(cm**-2)stat.error;phys.columnDensityfloatlogNHI-m[17.61/18.8]? Measured column density (3)log(cm**-2)phys.columnDensityfloatnullableSourceSource of column densities (5)meta.code;obscharRef[1/16]? Reference (4)meta.bibintnullableTSS25Display the HWO Target Stars and Systems 2025 list (Tuchow+2025, J/PASP/137/J4402) catalog datameta.ref.urlcharH24Display the Habitable Worlds Observatory (Harada+2024, J/ApJS/272/30) catalog datameta.ref.urlchar