J/MNRAS/475/2480ivo://CDS.VizieR/J/MNRAS/475/2480doi:10.26093/cds/vizier.74752480CDSPelisoli I.Kepler S.O.Koester D.2024-08-18T20:18:01Z2021-04-27T09:59:53ZCDS support team

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

cds-question@unistra.frdwarf-starssubdwarf-starswhite-dwarf-starseffective-temperatureThe so-called sdA stars are defined by having H-rich spectra and surface gravities similar to hot subdwarf stars, but effective temperature below the zero-age horizontal branch. Their evolutionary history is an enigma: their surface gravity is too high for main-sequence stars, but too low for single evolution white dwarfs. They are most likely byproducts of binary evolution, including blue-stragglers, extremely-low mass white dwarf stars (ELMs) and their precursors (pre-ELMs). A small number of ELMs with similar properties to sdAs is known. Other possibilities include metal-poor A/F dwarfs, second generation stars, or even stars accreted from dwarf galaxies. In this work, we analyse colours, proper motions, and spacial velocities of a sample of sdAs from the Sloan Digital Sky Survey to assess their nature and evolutionary origin. We define a probability of belonging to the main sequence and a probability of being a (pre-)ELM based on these properties. We find that 7 per cent of the sdAs are more likely to be (pre-)ELMs than main-sequence stars. However, the spacial velocity distribution suggests that over 35 per cent of them cannot be explained as single metal-poor A/F stars.2018MNRAS.475.2480Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/475/2480CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/600/A50 : Catalog of hot subdwarf stars (Geier+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/475/2480https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/475/2480http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/475/2480https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/475/2480https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/475/2480http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/475/2480GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/475/2480/table1 (Obtained values of Teff and logg for the 408 analysed SDSS objects in the range 5.5<=logg<7.0 and 7000<=Teff<=20000K)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/475/2480/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/475/2480/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/475/2480/table1?GETtext/xml+votable180.050000true171.5694167-1.02797220.005555555555555556Cone search capability for table J/MNRAS/475/2480/table2 (Objects with a higher probability of being (pre-)ELM compared to main sequence)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/475/2480/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/475/2480/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/475/2480/table2?GETtext/xml+votable180.050000true152.7245417-0.70502780.005555555555555556Cone search capability for table J/MNRAS/475/2480/tablec1 (Objects for which our fit indicated Teff>20000K and logg<6.5, which are possible hot subdwarfs not listed in Geier et al. (2017, Cat. J/A+A/600/A50))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/475/2480/tablec1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/475/2480/tablec1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/475/2480/tablec1?GETtext/xml+votable180.050000true0.4092528.45886110.0055555555555555565/2066 2129 2324 2343 2372 4985 7976 12222 6/22 29 64 417 420 700 716 727 736 903 970 974 990 1014 1697 1699-1701 1703 2036-2037 2041 2064 2066 2204-2205 2248 2250 2285 2287 2296-2297 2299 2302-2303 2851 4053 4100 4109 4111 4124 4126 4128-4129 4138 4145 4167 4178 4185 4199 4213 4224 4230 4234 4257 4266 4271 4278 4287 4296 4300 4361 4373 4375 4414 4417-4418 4424 4426 4432 4435 4467 4476 4499 4524 4537 4591 4608 4612 4625 4632 4657 4664 4670 4679 4692 4694 4708 4712 4734 4743-4745 4747 4750 4771-4774 4779 4787 4800-4801 4808 4813 4823 4834 4843 4873 4880 4896 4906 4919 4942 4948 4953 4972 4977 4999 5035 5054 5067 5071 5083 5106 5132 5145-5146 5157 5168 5190 5230 5250-5251 5254 5266-5267 5289 5311 5325 5357 5370 5373 5450 5467 5545 5549 5561 5575 5577-5579 5586 5588 5647 5668 5727 5767 5878 5888 5890 5894 5910 5915 5973 6029 6051-6052 6093-6094 6098 6104 6106 6117 6124 6131 6142 6160 6162 6199 6205 6216-6217 6219 6251 6255-6256 6258 6271 6312 6342 6358 6367 6381 6387 6396 6402 6405 6501 6508 6532 6553 6568 6570 6582 6594 6597 6705 6928 6933 7159 7162-7163 7165 7177 7185-7186 7188 7227 7251 7311 7350 7363 7370 7433 7452 7460 7462 7466 7480-7481 7487 7503 7513-7516 7536 7553 7568-7569 7778 7785-7786 7788 8127 8143 8170 8252 8261-8262 8331 8335 8341 8353 8356 8392 8394 8407 8486 8497 8513 8523 8526-8528 8530 8540 8544 8546 8549 8583 8589 8592 8600 8624 8631 8636 8654 8665 8670-8671 8678 8685 8692 8723 8737 8751 8763 8793 8796 8815 8843 8853 8858-8859 8862 8865 8876 8973-8974 8996-8997 9024 9040 9045-9046 9070 9077 9083 9090 9100 9121 9124 9127 9135 9156 9163 9166 9185 9210 9215 9220 9228 9235-9236 9240 9245 9248 9251 9267-9268 9270-9271 9274 9277 9286-9287 9300 9311 9316-9317 9319 9323-9325 9327 9330 9334-9335 9337-9338 9341-9342 9359 9369 9378-9379 9386 9392 9394 9396-9398 9410 9412-9413 9418 9427 9430 9433-9434 9436 9438 9447-9448 9457 9466 9470 9475 9482 9486 9494 9496-9497 9499 9504 9512 9514 9516 9518 9530 9576 9578 9582 9594 9605 9609 9611 9613-9616 9619 9622-9623 9626-9627 9629 9632 9636 9648 9652 9664 9666 9668 9740 9747 9749 9756-9757 9776 9789 9792 9794 9796 9798 9802 9810 9816 9818 9823-9825 9832 9835-9836 9838-9839 9845-9847 9849 9851 9854 9862-9863 9869 9873 9880 9890 9903-9904 9911 9914 9924 9926-9927 9932-9933 9938 9949 9968 9973 10042 10084-10085 10092 10113 10118 10122 10124 10138 10146-10147 10189 10192 10202 10223 10235 10240 10257 10260 10262 10314 10333 10336 10416 10421 10490 10521 10536 10541 10546 10552 10565-10566 10571 10590 10604 10611 10613 10621 10640 10675-10676 10685 10694 10700 10703 10715 10737 10768 10793 10795 10821 10828-10829 10838 10879 10918 10920 10951 10959 10961 10965 10986 10990 11028 11043 11049 11053 11066 11081 11089-11090 11096 11120 11128 11133 11140 11163 11171 11175 11185 11188 11190 11213 11221-11222 11225 11228 11236 11244 11249-11250 11254 11260 11264 11286 11332 11336 11341 11343 11346 11349 11367 11378 11390 11394 11397 11422 11426 11437-11438 11445 11448 11450-11451 11465 11471-11472 11488 11496 11504 11548 11557 11575 11601 11829 11838 11874 11880 11882-11883 11920 11924 11949 11952 12288 12299 12320 12373 12388-12390 12396-12397 12401-12402 12404-12405 12524-12526 12538 12638 12662 12760 12805 12816-12818 12866 13332 13411 13415 13509 13560-13561 13648-13649 13658 13683 13777 13784 13893 13905 13908 14156 14158-14159 14168 14567 14572 14574-14575 14584-14585 14911 14916 14919 14922 14993 14998-14999 15327 15350-15351 15915 15930 16011 16035 16127 16270 16272 16274 16276 16289 16292-16293 17235 17238 17243 17253 17257 17264 17294-17295 17322 17325 17363 17368 17371 17397 17515 17549 17554 17562 17664 17676 17745 17752 17764 17766 17769 17771 17776 17810-17811 17816 17830-17831 17836 17852 17902 17906 17976 17982-17983 18005 18010 18012-18014 18020 18023 18025 18027 18061 18063 18070 18073 18087 18090 18169 18171 18223 18226 18233 18235-18236 18238 18295 18308 18381 18416 18520 18523 18546 18582 18609 18614 18687 18750 18766-18767 18789 18795 18834 18843 18854 18857-18858 19032 19036 19054 19089 19091 19094-19095 19108 19115-19116 19118 19125 19138 19165 19186 19200 19243 19269 19271 19282 19334 19336 19410 19412 19416-19417 19597 19639 19686-19687 19698 19727 19736-19737 19739 19747 19757 19768 19782-19783 19791 19834 19907 19946 19952 19999 20032-20034 20125 20168-20169 20171-20172 20181 20184 20248-20250 20273 20275 20277 20279 20285 20287 20436 20454-20455 20461 20466 21591 21762 21768 21771 21788 21821 21823 21846 21910-21911 21973 21975 21996 21998 22009 22011 22014 22077 22341-22342 22351 22364 22397 22513-22514 22517 22520 22650 22717 22737 22740-22741 22826-22827 23204-23205 23208 23210 23683 24055 24061 24063 25288 25290 25313 25329 25332 25337 25519 25529 25588 25590 25688 25690 25692 25694 25848 25910 25912 25937-25938 25941 25945 25947 25950 25952 25960 25975 25988 26003 26012 26020-26022 26094 26103 26112 26114-26115 26118 26161 26163 26167 26171-26173 26177 26180 26188 26191 26193 26195 26197 26199-26201 26203 26205 26210 26213 26215 26222 26224 26227 26230 26236 26254-26255 26257 26265-26266 26268-26269 26273-26276 26278-26279 26281-26282 26285 26301 26309-26311 26328 26332 26346 26350 26354 26365-26366 26372 26416 26440 26465 26472-26473 26476-26477 26496 26536 26548 26550 26584 26593 26603 26945 26958 26970 26974 26977 26979 26981-26982 26994 27005 27035 27043 27045-27046 27063 27065 27071 27080 27097 27099 27105 27116 27224 27231-27233 27235 27238-27239 27247 27256 27285 27287 27309 27312 27325 27353 27374 27384 27415 27423 27451 27470 27491 27494 27507 27524-27525 27527 27536 27541 27562 27582 27606 27612 27614 27630 27642 27667 27671 27677 27685-27687 27694 27699 27701 27705 27718 27731 27745 27811 27822 27828 27851 27854 27858 27872 27905 27909 27932 27939 27941-27942 27949 27952 27965 27969 27984 27986 27994 27998 28014 28017 28054 28072-28073 28075-28076 28082 28094 28162 28203 28216 28223 28270 28288 28313 28318 28323 28326 28344 28441 28515 28524 28527 28547 28550 28566 28587 28612 28620 28655 29777 29779-29780 30029 30031 30035 30041-30042 30044 30974 31145-31146 31318 31333 31337 31358 31366 31374 31377 31381 31410 31413 31435 31445 31449-31450 31452 31528-31529 31532 31546 31603 31609 31612-31613 31615 31617-31619 31622 31624 31632 31648 31653 31655 31664 31672 31684 31686 31691 31694 31698 31705-31707 31712 31715 31731 31736-31737 31742 31882 31908 31910 32061 32104 32399 32402-32403 32409 32414 32429-32430 32432 32434 32436 32441 32444-32445 32447 32459 32478-32479 32482 32486 32488 32494 32500 32502 32519 32525 32527 32537 32554-32555 32558-32559 32644 32650 32672 32682 32685-32686 32697 32699 36730 36781 36790 36805 45053-45054 48859 48862 48880-48881 48883 48885-48886 48892 49020 49084-49085 49106 49120 49122 49128https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/475/2480?format=asciidefaultJ/MNRAS/475/2480/table1Obtained values of Teff and logg for the 408 analysed SDSS objects in the range 5.5<=logg<7.0 and 7000<=Teff<=20000KSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS designation (HHMMSS.ss+DDMMSS.s)meta.id;meta.maincharPMFSDSS Plate-MJD-Fiber identifiermeta.idcharSNRgSignal-to-noise ratio in g bandstat.snr;instr.bandpassfloatTeffEffective temperatureKphys.temperature.effectiveinte_Teffrms uncertainty on Teff (1)Kstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggrms uncertainty on logg (1)log(cm.s**-2)stat.errorfloatSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlchar_RARight ascension (derived from SDSS) for Eq=J2000degpos.eq.ra;meta.main_DEDeclination (derived from SDSS) for Eq=J2000degpos.eq.dec;meta.mainJ/MNRAS/475/2480/table2Objects with a higher probability of being (pre-)ELM compared to main sequenceSimbadNameSimbad column added by the CDSmeta.idcharnullablePMFSDSS Plate-MJD-Fiber identifiermeta.idcharTeffEffective temperatureKphys.temperature.effectiveinte_Teffrms uncertainty on TeffKstat.error;phys.temperature.effectiveintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS designation (HHMMSS.ss+DDMMSS.s)meta.id;meta.maincharloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggrms uncertainty on logglog(cm.s**-2)stat.errorfloatpMSProbability of being main sequencestat.fit.goodnessfloatpELMProbability of being extremely-low mass white dwarf star (ELM)stat.fit.goodnessfloatSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlchar_RARight ascension (derived from SDSS) for Eq=J2000degpos.eq.ra;meta.main_DEDeclination (derived from SDSS) for Eq=J2000degpos.eq.dec;meta.mainJ/MNRAS/475/2480/tablec1Objects for which our fit indicated Teff>20000K and logg<6.5, which are possible hot subdwarfs not listed in Geier et al. (2017, Cat. J/A+A/600/A50)SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS designation (HHMMSS.ss+DDMMSS.s)meta.id;meta.maincharPMFSDSS Plate-MJD-Fiber identifiermeta.idcharPMF2Second SDSS Plate-MJD-Fiber identifiermeta.idcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlchar_RARight ascension (derived from SDSS) for Eq=J2000degpos.eq.ra;meta.main_DEDeclination (derived from SDSS) for Eq=J2000degpos.eq.dec;meta.main