J/A+A/661/A113ivo://CDS.VizieR/J/A+A/661/A113doi:10.26093/cds/vizier.36610113CDSGeier S.Dorsch M.Pelisoli I.Reindl N.Heber U.Irrgang A.2023-11-03T12:28:43Z2022-05-12T12:01:45ZCDS support team

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

cds-question@unistra.frsubdwarf-starseffective-temperaturechemical-abundancesradial-velocityvisible-astronomyHot subdwarf stars represent a late and peculiar stage in the evolution of low-mass stars, since they are likely formed by close binary interactions. In this work, we perform a radial velocity (RV) variability study of a sample of 646 hot subdwarfs with multi-epoch radial velocities based on spectra from Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST). The atmospheric parameters and RVs were taken from the literature. For stars with archival spectra but without literature values, we determined the parameters by fitting model atmospheres. In addition, we redetermined the atmospheric parameters and RVs for all the He-enriched sdO/Bs. This broad sample allowed us to study RV-variability as a function of the location in the Teff-logg- and Teff-logn(He)/n(H) diagrams in a statistically significant way. We used the fraction of RV-variable stars and the distribution of the maximum RV variations {DELTA}RVmax as diagnostics. Both indicators turned out to be quite inhomogeneous across the studied parameter ranges. A striking feature is the completely dissimilar behaviour of He-poor and He-rich hot subdwarfs. While the former have a high fraction of close binaries, almost no significant RV variations could be detected for the latter. This has led us to the conclusion that there is likely no evolutionary connection between these subtypes. On the other hand, intermediate He-rich- and extreme He-rich sdOB/Os are more likely to be related. Furthermore, we conclude that the vast majority of this population is formed via one or several binary merger channels. Hot subdwarfs with temperatures cooler than ~24000K tend to show fewer and smaller RV-variations. These objects might constitute a new subpopulation of binaries with longer periods and late-type or compact companions. The RV-variability properties of the extreme horizontal branch (EHB) and corresponding post-EHB populations of the He-poor hot subdwarfs match and confirm the predicted evolutionary connection between them. Stars found below the canonical EHB at somewhat higher surface gravities show large RV variations and a high RV variability fraction. These properties are consistent with most of them being low-mass EHB stars or progenitors of low-mass helium white dwarfs in close binaries.2022A&A...661A.113Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/661/A113CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/661/A113https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/661/A113http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/661/A113https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/661/A113https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/661/A113http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/661/A113GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/661/A113/tablea1 (Catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/661/A113/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/661/A113/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/661/A113/tablea1?GETtext/xml+votable180.050000true0.278040211.01008990.0055555555555555566/21 64 132 399 457 485 496 550 723 823 829 865 872 1009 1154 1158 1162 1177 1185 1202 1310 1348 1542 1563-1564 1570 1572 1602 1672 1684 1712 2162 2198 2233 2246 2302 2584 2591 2593 2600 2621 2625-2626 2636 2707 2709 2753 3213 3588 4105-4106 4108 4122 4164 4174 4216 4224 4231 4242 4258 4293 4297 4308 4319 4345-4346 4378 4397 4406 4434 4456 4476 4497 4531 4541 4566 4598 4604 4613 4624 4630 4634 4644 4648 4658 4664 4674 4680 4697 4704 4709 4712 4739 4741 4746 4753 4757 4773 4782 4784 4790 4797 4838 4848 4858 4860 4872 4898 4931 4934 4938 4943 4955 4957-4958 4960 5057 5062 5150 5155 5184 5199 5204 5206 5252 5287 5289 5291 5369 5371 5396 5406 5430 5544 5586 5639 5654-5655 5710 5724 5749 5804 5816 5823 5836-5838 5847 5918 5922 5943-5944 5972 6002 6011 6034 6049 6103 6171 6173-6174 6177 6198 6208 6246-6247 6251 6266-6267 6270 6276 6283 6295 6305-6306 6348-6349 6385 6410 6446 6455 6458 6475-6476 6497 6504 6507 6552 6562 6567 6579-6580 6588 6613 6617 6635 6646 6670 6684 6696 6710 6737 6741 6757 6772 6848 7242 7259-7260 7282 7296 7318 7384 7404 7410 7412 7510 8200 8240 8242-8243 8265 8281 8283-8284 8298 8309-8310 8341 8397 8412 8493 8538 8550 8589 8635 8669-8671 8723 8733 8736 8746 8770 8793 8807 8833 8875 8891 8956 8959 8968 8982 8992 9035 9061 9077 9119 9123 9130 9155 9211 9213 9217-9218 9229 9232 9234 9237 9268-9270 9299 9320-9321 9357 9366 9373 9384 9393-9394 9410 9416 9419 9427-9428 9436 9445 9447 9506 9516 9520 9524 9529 9534 9605 9633 9649 9671 9730 9762 9790 9798 9812 9840 9882 9928 9969 9975 9991 10024 10072 10083 10132 10144 10221 10254 10261 10296 10318 10356 10378-10379 10382 10397 10400 10409 10418 10439-10440 10766 10790 10872 10903 10914 10945 10963 11029 11038 11047 11144 11180 11189 11194 11218 11275 11294 11300 11335 11359 11397 11401 11512 11810 11876 11946 12560 12655 12657-12658 12668 12717 12720 13324 13413 13415 13426 13563 13601 14578 14772 14775 14779 14943 14960 14997 15110 16032 17769 18027 18088 18114 18232 18409 18687 18789 18854 18863 18926 18949 19037 19045 19051-19052 19057 19068 19086 19091 19098-19099 19108 19110 19113 19118 19120 19122 19135 19157 19382 19386-19388 19410 19419 19427 19649 19822 19875 19905 19953 20066 20072 20154 20224 20250 20261 20478 21803-21804 21885 22339 22389 22398 22438 22463 22482 22484-22485 22494 22503 22850 22889 23065 23157 23160 23207 23510 23531 23777 23790 23812 23919 23929 23973 23992 24025 24055 24059 24111 24124 24136 24242 24330 24340 24391 24397 24404 24415 24446 24529 24532-24533 25582 25845 25855 25910 25921 25927 25932 25950 25952 25956 25967 25969-25970 25976 25996 26002 26015 26020 26040 26077 26085 26164 26175 26206 26210 26316-26317 26343 26356 26396 26436 26443 26464 26518-26519 26533 26553 26555 26567 26606 26609 26615 26870 26943 26989 26991 27000 27026 27045 27057 27061 27125 27215 27227 27317 27321 27324 27343 27345 27352 27478 27495 27562 27632 27693 27703 27741 27776 27782 27817 27828 27834 27895 27918 27956 27964 27975 28001 28016 28035 28086 28129 28262 28305 28321 28323 28370 28377 28406 28408 28420 28423 28440 28465 28579 28586-28587 28591 28607 28646 31138 31146-31147 31319 31330 31339 31386-31387 31392 31404-31405 31413 31435 31448 31469 31473 31528 31530 31549 31613 31617 31622 31630 31642 31644 31646 31653 31665 31673 31679 31686-31687 31694 31705 31719 31723 31734 31740-31741 32397 32429 32433 32436-32438 32442 32458-32459 32483 32486 32489 32555 32697 49079 49122https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/661/A113?format=asciiOpticaldefaultJ/A+A/661/A113/tablea1CatalogueSimbadNameSimbad column added by the CDSmeta.idcharnullablel_loggLower limit flag on loggmeta.code.errorcharRVavInverse-variance weighted mean RVkm/sphys.veloc;pos.heliocentricinte_RVavInverse-variance weighted mean RV errorkm/sstat.errorintdRVmaxMaximum RV shiftkm/sphys.velocinte_dRVmaxMaximum RV shift errorkm/sstat.errorintlogPLOG10 of false-alarm probabilitystat.fit.goodnessdoubleTeffEffective temperatureKphys.temperature.effectiveinte_TeffEffective temperature errorKstat.error;phys.temperature.effectiveintlogglog10 surface gravitylog(cm.s**-2)phys.gravityfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordinte_logg? Error on log10 surface gravitylog(cm.s**-2)stat.errorfloatnullablelogYlog10 helium abundance n(He)/n(H)phys.abund.Yfloate_logYError log10 helium abundancestat.error;pos.cartesian.yfloatRefReference for atmo parameters (Bibcode)meta.ref;pos.framecharNameTarget namemeta.id;meta.maincharGaiaDR2? Gaia DR2 designation (source_id)meta.idnullableRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainSpClassSpectroscopic classificationsrc.classcharNEpochNumber of single RV epochsmeta.numberint