J/AJ/126/1455ivo://CDS.VizieR/J/AJ/126/1455doi:10.26093/cds/vizier.51261455CDSStark M.A.Wade R.A.2023-04-06T16:50:57Z2005-08-22T08:30:40ZCDS support team

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

cds-question@unistra.frearly-type-starsinfrared-photometrysubdwarf-starshorizontal-branch-starsUtilizing the Two Micron All Sky Survey (2MASS) Second Incremental Data Release Catalog, we have retrieved near-IR magnitudes for several hundred hot subdwarfs (sdO and sdB stars) drawn from the Catalogue of Spectroscopically Identified Hot Subdwarfs by Kilkenny et al. (1988SAAOC..12....1K). This sample size greatly exceeds that of previous studies of hot subdwarfs. Examining 2MASS photometry alone or in combination with visual photometry (Johnson BV or Stroemgren uvby) available in the literature, we show that it is possible to identify hot subdwarf stars that exhibit atypically red IR colors, which can be attributed to the presence of an unresolved late-type companion. Utilizing this large sample, we attempt for the first time to define an approximately volume-limited sample of hot subdwarfs. We discuss the considerations, biases, and difficulties in defining such a sample. We find that, of the hot subdwarfs in Kilkenny et al. (1988SAAOC..12....1K), about 40% in a magnitude-limited sample have colors that are consistent with the presence of an unresolved late-type companion. Binary stars are overrepresented in a magnitude-limited sample. In an approximately volume-limited sample the fraction of composite-color binaries is about 30%.2003AJ....126.1455Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/126/1455CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/126/1455https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/126/1455http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/126/1455https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/126/1455https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/126/1455http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/126/1455GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/126/1455/catalog (All subdwarfs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/126/1455/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/126/1455/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/126/1455/catalog?GETtext/xml+votable180.050000true0.38452083-5.321322220.0055555555555555566/226 398 530 538 546 548 560 564 573 596 664 689 709 715 718 729 1429 1650 1792 2083 2094 2178 2180 2188 2437 2877 2958 3094 4285 4293 4295 4297 4319-4320 4346 4382 4390 4399 4409 4456 4481 4497 4515-4516 4529 4566 4676 4689 4692 4898 4902 4929 4931 4938 4943 4955 4957 4976 4982 5019 5025 5047 5057 5113 5117 5134 5137 5157 5204 5206-5207 5236 5296 5388 5396 5466 5544 5550 5584 5586 5654-5655 5690 5698 5710 5724 5818 5835 5843 5920 5944 6002 6107-6108 6113 6118 6130 6333 6401 6471 6477 6486 6544 6547 6553 6609 6616 6646 7530 7583 7626 7772 7946 8006 8016 8068 8077 8311 8391 8447 8467 8469 8500 8518 8570 8615 8635 8770 8775 8791 8923 8930 8932 8936 8940 8960 8998 9053 9099 9102 9180 9215 9302 9319 9328 9332 9372 9382 9426-9427 9464-9465 9497 9501 9510 9512 9516 9521 9617 9620 9624 9630 9633 9640 9661 9683 9733 9790 9812 9819 9841 9843 9853 9886 9899 9905 9908-9909 9911 9927 9935 9940 9951 9954 9959 9969 9981 10007 10011 10019 10024 10044 10048 10060 10123 10125 10132-10133 10135 10144 10146 10159 10171 10213 10216 10309 10315 10322 10333 10376 10379 10409 10471 10475 10489 10504 10514 10536 10543 10563 10593 10599 10602 10624 10629 10636 10640 10744 10774 10903 10963 10969 10973 11016 11029 11047 11109 11113 11144-11145 11171 11242 11296 11300 11302 11308 11314 11409 11467 11479 11486 11576 11652 11680 11786 11793 11795 11798-11799 11810 11875 11942 12023 12070 12412 12501 12576 12585 12590-12591 12615 12640 12910 12922 12961 13009 13266 13283 13286 13806 13999 14111 14125 14135 14148-14149 14485 14669 14756 14764 14770 14793 15065 16046 16406 16410-16411 16430 16534 16537 16581 16588 16592 16602 16672 16749 16768 17147 17159 17162 17268 17323 17359 17401 17450 17534 17570 17636 17726 18072 18391 18395 18418 18478 18498 18548 18550 18576 18589 18701 18712 18716 18748 18848 18966 19016 19033 19388 19398 19404 19410 19415 19419 19436 19444 19451 19475 19666 19692 19705 19726 19741 19752 19783 19802 19822 19863 19893 19898 19909 19923 19942 19984 20002 20014 20056 20059 20184 20207 20224 20259 20282 20314 20358 20373 20390 21804 22100 22102 22169 22660 23103 23510-23511 23516 23527 23531 23545 23806 23845 23992 23995 24075 24120 24124 24148 24150 24204 25068 25076 25079 25087 25388 25399-25400 25412 25469 25477 25484 25489 25545 25576 25582 25586 25647-25648 25651 25740 25751 25759 25855 25896 25921 25927 25990 25996 26112 26138 26164 26184 26299 26495 26569-26570 26609 26666 26724 26737 26745 26748 26762 26768 26780 26791-26792 26794 26808 26819 26837 26854 26864 26872 26883 26889 26937 26959 26969 27026 27045 27175 27187 27300 27603 27620 27834 27859 27871 27915 27934 27963 27975 28034 28107 28111 28128 28266 28302 28327 28331 28335 28388 28390 28408 28415 28465 28586-28587 28622 28625 28637-28638 28646 28669 28973 30037 30776 31613 31676 31691 31708 31715 31721 31739 32072 32209 32385 32416 32456 32458 32686 32697 32752 33097 33795 33812 34737 34752 35562 35606 35640 35650 35707 35715 35718 35720 35767 35798 36186 36279 36293 36300 36307 36338 36791 36844 36851 39362 39735 39877 40919 40948 42463 44211 44258-44259 44638 44645 44789 45018 46563 46670 46672 46684 47537 47544 47558 47985 48314 48428 48434 48501 48516 48560 48658-48659 48665 48704 48752 48839 48845 48884 489337.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/126/1455?format=asciiInfrareddefaultJ/AJ/126/1455/catalogAll subdwarfsSimbadNameSimbad column added by the CDSmeta.idcharmagThe Filt band magnitudemagphot.magfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNotesIndividual remarks (5)meta.notecharSpTypeMK spectral typesrc.spTypecharu_B-magUncertainty flag on B-magmeta.code.errorchar2MASSDisplay the 2MASS datameta.ref.urlcharFiltFilter used in mag (4)instr.setupcharSeqSequence number assigned by us (G1)meta.id;meta.mainintn_Seq[*] indicates a note detailed in notes.datmeta.notecharB-mag? The (B-mag) colormagphot.colorfloatnullableIDFirst identifier that appears in KHD (Kilkenney et al., 1988SAAOC..12....1K)meta.idcharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainNoteIDNotes about the designations of the star (2)meta.notecharSIDThe SIMBAD identifier (3)meta.idcharJmagThe J-band magnitudemagphot.mag;em.IR.Jfloate_Jmag? The 1 {sigma} error in Jmag (2)magstat.error;phot.mag;em.IR.JfloatnullableHmagThe H-band magnitudemagphot.mag;em.IR.Hfloate_Hmag? The 1 {sigma} error in Hmag (2)magstat.error;phot.mag;em.IR.HfloatnullableKsmagThe K_s_ band magnitudemagphot.mag;em.IR.Kfloate_Ksmag? The 1 {sigma} error in Kmag (2)magstat.error;phot.mag;em.IR.Kfloatnullablel_J-KsLimit flag on J-Ksmeta.code.error;phot.color;em.IR.JcharJ-KsThe (J-Ks) color (3)magphot.color;em.IR.J;em.IR.Kfloate_J-Ks? The 1 {sigma} error in J-Ksmagstat.error;phot.color;em.IR.JfloatnullableJ/AJ/126/1455/notesIndividual notesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential numbermeta.recordintNoteText of the notemeta.notechar