J/A+A/692/A231ivo://CDS.VizieR/J/A+A/692/A231doi:10.26093/cds/vizier/bc-nm/lcdbCDSHummerich S.Bernhard K.Paunzen E.2026-07-03T06:36:19Z2025-07-23T10:39:38ZCDS support team

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

cds-question@unistra.frpeculiar-variable-starsap-starsphotometryvisible-astronomyThe magnetic chemically peculiar Ap stars exhibit an extreme spread of rotational velocities, the cause of which is not clearly understood. Ap stars with rotation periods of 50 days or longer are know as super-slowly rotating Ap (ssrAp) stars. Photometrically variable Ap stars are commonly termed {alpha}^2^ Canum Venaticorum (ACV) variables. Our study aims to enlarge the sample of known ssrAp stars using data from the Zwicky Transient Facility (ZTF) survey to enable more robust and significant statistical studies of these objects. Using selection criteria based on the known characteristics of ACV variables, candidate stars were gleaned from the ZTF catalogues of periodic and suspected variable stars and from ZTF raw data. ssrAp stars were identified from this list via their characteristic photometric properties, {DELTA}a photometry, and spectral classification. The final sample consists of 70 new ssrAp stars, which mostly exhibit rotation periods of between 50 and 200 days. The object with the longest period has a rotation period of 2551.7 days. We present astrophysical parameters and a Hertzsprung-Russell diagram for the complete sample of known ssrAp stars. With very few exceptions, the ssrAp stars are grouped in the middle of the main sequence with ages in excess of 150Myr. ZTF J021309.72+582827.7 was identified as a possible binary star harbouring an Ap star and a cool component, possibly shrouded in dust. With our study, we enlarge the sample of known ssrAp stars by about 150%, paving the way for more in-depth statistical studies.2024A&A...692A.231Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A231CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/692/A231https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/692/A231http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/692/A231https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/692/A231https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/692/A231http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/692/A231GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/692/A231/tablea1 (Astrophysical parameters and synthetic {DELTA}a photometry for the merged samples of ssrAp stars and candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A231/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A231/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A231/tablea1?GETtext/xml+votable180.050000true0.756416759.68297220.005555555555555556Cone search capability for table J/A+A/692/A231/tablea2 (Basic parameters for the newly identified sample of ssrAp stars and candidates.)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A231/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A231/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A231/tablea2?GETtext/xml+votable180.050000true0.756458359.68299720.0055555555555555566/1113 1320 1341 1426 1753 1815 1818 1820 2490 2543 2818 2874 2908 2967 2987 3007-3008 3030-3031 3035 3051 3054-3055 3059 3064 3067 3069 3132 3152 3167 3245-3246 3266-3267 3584 3591 3600-3601 3623 3629 3635-3637 3712 3714-3715 3724 3774 3812 13186 13788 13951 13998 14032-14034 14058 14065 14070 14077 14079 14108 14202 14207 14219 14225 14230 14268 14307 14315 14320 14354 14426 14502 14534 14638 14642 14730 14922 15360-15361 15375 15385 15408 15411 15420 15428 15440 15474 15487 15552 15555 15567 15572 15612 15624 15627 15654 15693-15694 15716 15757 16267 16288 18086 20340 20977 21296 21663 21691-21692 21696 21729 22033 22071 23612 23648 23665 23792 23871 24040 24335 24487 24546 25964 28688 30083 30122 30310 30331 30687 31096 32029 32092 32103 32209 37124 37181 37322 37629 38287 39175 39532 39877 41524 41692 42143 43014 43058 475391.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/692/A231?format=asciiOpticaldefaultJ/A+A/692/A231/tablea1Astrophysical parameters and synthetic {DELTA}a photometry for the merged samples of ssrAp stars and candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameIdentifiermeta.id;meta.maincharTeffEffective temperatureKphys.temperature.effectiveinte_TeffEffective temperature errorKstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggSurface gravity errorlog(cm.s**-2)stat.errorfloatg1-y? g1-y colour indexmagphot.colorfloatnullableaindex? a indexmagphot.colorfloatnullableDa? {DELTA}a valuemagstat.fit.residualfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from Simbad and table A2 (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad and table A2 (declination part)degpos.eq.dec;meta.mainJ/A+A/692/A231/tablea2Basic parameters for the newly identified sample of ssrAp stars and candidates.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameIdentifiermeta.id;meta.maincharRAJ2000Right ascension (J2000) from Gaia DR3pos.eq.ra;meta.mainDEJ2000Declination (J2000) from Gaia DR3pos.eq.dec;meta.mainSourceSource of data (1)meta.bibcharGmagGaia DR3 G magnitudemagphot.mag;em.optfloatPerPhotometric variability period, as derived in this studydsrc.varfloatSpTypeSpectral type, where available, as derived in this studysrc.spTypecharRemarkRemark (2)meta.notechar