J/A+A/693/A121ivo://CDS.VizieR/J/A+A/693/A121doi:10.26093/cds/vizier.36930121CDSHe R.Meng X.Lei Z.Yan H.Lan S.2025-03-03T20:01:05Z2025-01-09T12:41:23ZCDS support team

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

cds-question@unistra.frsubdwarf-starsmultiple-starsradial-velocityvisible-astronomyIt is generally thought that hot subdwarfs are helium-core- or helium-shell-burning objects with extremely thin hydrogen envelopes and that binary interactions are always needed in their formation. Different types of hot subdwarfs may have different origins, which will cause them to present different radial velocity (RV) variability properties. We plan to study the RV-variability fractions of different types of hot subdwarfs, as well as their distributions in the Teff-logg diagram. This provides insights into the formation of hot subdwarfs. The cross-correlation function method was adopted to measure RV variations in 434 hot subdwarfs based on spectra obtained with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Light curves from the Transiting Exoplanet Survey were also used to search for short-period binary hot subdwarfs. Only 6+/-4% of our single-lined He-rich hot subdwarfs that only show spectroscopic features of hot subdwarfs are found to be RV variable, which is lower than the fraction of single-lined He-poor sdB stars (31+/-3%). Single-lined sdB stars with effective temperatures (Teff)~25000-33000K show an RV-variability fraction of 34+/-5%, while lower RV-variability fractions are observed for single-lined sdB stars cooler than about 25000K (11+/-4%), single-lined sdB/OB stars with Teff~33000-40000K and surface gravities ~5.7-6.0(13+/-3%), as well as single-lined sdO/B stars with Teff~45000-70000K (10+/-7%). Single-lined hot subdwarfs with Teff~35000-45000K located above the extreme horizontal branch (EHB) show a similar RV-variability fraction of 34+/-9% as single-lined sdB stars at about 25000-33000K. The largest RV-variability fraction of 51+/-8% is found in single-lined hot subdwarfs below the canonical EHB. The detected RV-variability fraction of our composite hot subdwarfs with an infrared excess in their spectral energy distributions is 9+/-3%, which is lower than that fraction of single-lined hot subdwarfs. Since the average RV uncertainty we measured in the LAMOST spectra is about 7.0km/s, the lower detected RV-variability fraction for composite hot subdwarfs is expected because the RV amplitudes associated with long-period systems are lower. The results here are generally consistent with the canonical binary evolution channels for forming hot subdwarfs. Most single-lined He-rich hot subdwarfs may form through merger channels, while the stable Roche-lobe overflow channel could play an important role in the formation of composite hot subdwarfs. Single-lined hot subdwarfs with Teff~35000-45000K located above the EHB may have an evolutionary connection to the sdB stars at about 25000-33000K. The different detected RV-variability fractions for the different subclasses of single-lined hot subdwarfs indicate that their formation channels may differ.2025A&A...693A.121Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/693/A121CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/156 : LAMOST DR7 catalogs (Luo+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/693/A121https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/693/A121http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/693/A121https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/693/A121https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/693/A121http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/693/A121GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/693/A121/tablea1 (The RV variations and atmospheric parameters of 434 hot subdwarfs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/693/A121/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/693/A121/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/693/A121/tablea1?GETtext/xml+votable180.050000true0.076722.300790.0055555555555555566/64 97 255 285 457 478 655 718 723 823 874 907 944 958 1009 1154 1158 1162 1202 1310 1348 1362 1563 1572 1602 1672 1684 1712 1724 1760 2106 2221 2231 2233 2243 2246 2349 2363 2370 2410-2411 2424 2445 2458 2498 2593 2600 2616 2625-2626 2661 2783 2823 2843 2850 2852 2871 2873 3089 4104-4105 4164 4174 4258 4285 4293 4295 4297 4345-4346 4374 4382 4399 4409 4497 4541 4576 4598 4604 4630 4658 4663-4664 4674 4689 4697 4704 4709 4711 4716 4739 4741 4782 4800 4817 4838 4858 4872 4898 4931 4938 4943 4955 4957 4960 5036 5057 5113 5199 5204 5206 5252 5345 5406 5544 5586 5620 5655 5690 5698 5710 5724 5866 5884 5908 5918 6002 6034 6145 6171 6173-6175 6177 6196 6198 6208 6251 6254 6276 6283 6295 6305 6342 6348-6349 6385 6455 6477 6613 6617 6659 6661 6684 6696 6707 6772 6848 6850 6892 6955 6981 6991 7023 7057 7259 8212 8278 8281 8283 8325 8425 8623 8670-8671 8696 8699 8707 8729 8746 8770 8791 8829 8833 8873 8928 8982 8998 9026 9061 9119 9130 9215 9268 9299 9350 9366 9470 9664 9762 9775 9790 9812 9886 9905 9911 9981 10072 10083 10088 10120 10132 10144 10146 10296 10335 10376 10378-10379 10382 10398 10400 10440 10471 10504 10514 10552 10602 10624 10715 10782 10888 10903 10919 10948 10963 10973 11029 11038 11047 11144 11157 11194 11264 11303 11335 11375 11810 12358 12501 12591 12673 12697 12717 12720 12775 13319 13404 13437 13601 13607 13690 13811 14578 14763 14775 14779 14920 14943 14960 14997 15108 15132 15137 15152 15200 17884 18098 18125 18132 18344 18409 18687 18863 19068 19071 19118 19157 19288 19386 19410 19468 19875 20072 20187 20215 20236-20237 20478 21803-21804 21829-21830 21867 21879 22248 22261 22334 22339 22379 22387 22422 22438 22452 22471 22474 22477-22478 22482 22484 22503 22889 23157 23207 23356 23444 23510 23531 23545 23648 23658 23762 23777 23790 23879 23883 23893 23925 23929 23933 23972-23973 23992 24005 24025 24028 24063 24111 24124 24242 24330 24340 24391 24397 24400 24415 24446 24475 24529 24531-24533 25582 25969 25996 26015 26022 26066 26106 26164 26184 26193 26319 26553 26598 26609 27000 27095 27126 27227 27317 27321 27345 27478 27632 27713 27731 27814 27817 27834 27861 27912 27918 27956 27975 28185 28323 28331 28370 28388 28398 28465 28579 28622 28625 30196 31286 31359 31381 31392 31411 31413 31419 31528 31549 31613 31624 31640 31683 31715 31912 32142 32161 32335 32354 32550 32659 45046https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/693/A121?format=asciiOpticaldefaultJ/A+A/693/A121/tablea1The RV variations and atmospheric parameters of 434 hot subdwarfsRAJ2000LAMOST Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000LAMOST Declination (J2000)degpos.eq.dec;meta.maine_TeffEffective temperature errorKstat.error;phys.temperature.effectiveintlogglog10 surface gravitylog(cm.s**-2)phys.gravityfloate_loggError on log10 surface gravitylog(cm.s**-2)stat.errorfloatlogYlog10 helium abundance n(He)/n(H)phys.abund.Yfloate_logYError on log10 n(He)/n(H)stat.error;pos.cartesian.yfloatSingle-lined[is no] Single-lined or compositemeta.codecharSpClassSpectroscopic classificationmeta.code.class;src.classcharlogP? Log10 of false-alarm probabilitystat.fit.goodnessfloatnullableNEpochNumber of single RV epochsmeta.numberintdRVmaxMaximum RV shiftkm/sphys.veloc;arith.diffinte_dRVmaxError on maximum RV shiftkm/sstat.errorintLAMOSTDisplay the LAMOST DR7 data (Cat. V/156)meta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadNameSimbad column added by the CDSmeta.idcharnullableTeffEffective temperatureKphys.temperature.effectiveint