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J/AJ/126/1455       2MASS photometry of hot subdwarf stars   (Stark+, 2003)

Single and composite hot subdwarf stars in the light of 2MASS photometry. Stark M.A., Wade R.A. <Astron. J. 126, 1455 (2003)> =2003AJ....126.1455S
ADC_Keywords: Stars, early-type ; Photometry, infrared ; Stars, subdwarf ; Stars, horizontal branch Keywords: binaries: general - infrared radiation - stars: early-type - stars: horizontal-branch - subdwarfs Abstract: Utilizing 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%. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 133 593 Updated Coordinates and Notes for All Subdwarfs with a 2MASS 2IDR Identification (ordered by R.A.) table2.dat 120 593 Magnitudes and Colors for All Subdwarfs (ordered by J2000 R.A.) notes.dat 79 26 Individual notes
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Seq Sequence number assigned by us (G1) 5 A1 --- n_Seq [*] indicates a note detailed in notes.dat 6- 22 A17 --- ID First identifier that appears in KHD (Kilkenney et al., 1988SAAOC..12....1K) 24- 25 I2 h RAh Hour of right ascension (J2000) 27- 28 I2 min RAm Minute of right ascension (J2000) 30- 35 F6.3 s RAs Second of right ascension (J2000) 37 A1 --- DE- Sign of the declination (J2000) 38- 39 I2 deg DEd Degree of declination (J2000) 41- 42 I2 arcmin DEm Arcminute of declination (J2000) 44- 48 F5.2 arcsec DEs Arcsecond of declination (J2000) 50- 59 A10 --- SpType MK spectral type 61- 98 A38 --- NoteID Notes about the designations of the star (2) 100-133 A34 --- SID The SIMBAD identifier (3)
Note (2): Note on Seq: #NNNN (hash sign followed by a number) indicates a duplicate entry in KHD (Kilkenney et al., 1988SAAOC..12....1K) (the duplicate entry is not otherwise listed in this table). Note (3): The identifiers are consistent with SIMBAD nomenclature. For example, the designator CSHK 22876-35 used by KHD for star No. 8 in this table is equivalent to the SIMBAD designator BPS CS 22876-35, and the designator PG 23595+1942 used by KHD for star No. 1527 in this table is equivalent to the SIMBAD designator PG 2359+197. If no other ID is given, the identifier from KHD (given in column ID) is consistent with SIMBAD. In this way, one SIMBAD-compliant designator is available for cross-reference. The exceptions are the "HS" star No. 390 HS 1000+4704, the "SC" star No. 1165 SC 1721-3338 from Reid et al. (1988AJ.....96..275R), and the "LBQS" stars from Berg et al. (1992ApJS...78..409B), Nos. 41, 565, and 1405, which are not presently recognized by SIMBAD, although SIMBAD does use the LBQS designator for quasars from Hewett et al. (1995AJ....109.1498H).
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Seq Sequence number (G1) 5 A1 --- n_Seq [*] Individual note in notes.dat file 6- 22 A17 --- ID First identifier that appears in KHD (Kilkenney et al., 1988SAAOC..12....1K) 25- 30 F6.3 mag Jmag The J-band magnitude 32- 36 F5.3 mag e_Jmag ? The 1 σ error in Jmag (2) 38- 43 F6.3 mag Hmag The H-band magnitude 45- 49 F5.3 mag e_Hmag ? The 1 σ error in Hmag (2) 51- 56 F6.3 mag Ksmag The Ks band magnitude 58- 62 F5.3 mag e_Ksmag ? The 1 σ error in Kmag (2) 64 A1 --- l_J-Ks Limit flag on J-Ks 66- 71 F6.3 mag J-Ks The (J-Ks) color (3) 73- 77 F5.3 mag e_J-Ks ? The 1 σ error in J-Ks 79- 84 F6.3 mag mag The Filt band magnitude 85 A1 --- Filt Filter used in mag (4) 87- 92 F6.3 mag B-mag ? The (B-mag) color 93 A1 --- u_B-mag Uncertainty flag on B-mag 95-104 A10 --- SpType MK spectral type 106-120 A15 --- Notes Individual remarks (5)
Note (2): If no error is listed, then the star was not detected in that band, and the quoted magnitude is a 95% confidence upper limit. Note (3): The reported value is the maximum color index when an upper limit on Kmag is reported, and it is the minimum color index for an upper limit on Jmag. Note (4): Johnson V band unless noted as follows: y = Stroemgren y P = Photographic visual magnitude J = Photographic J magnitude B = Photographic B magnitude : = Uncertain magnitude Note (5): Note on Seq as follows: s = Reported single sdB or sdO star used to determine the single hot subdwarf locus (see Section 3.1 and Fig. 1); c = Reported composite sdB or sdO star used to determine the composite hot subdwarf locus (see Section 3.1 and Fig. 1); CC = 2MASS magnitudes listed are for a nearby companion only (the hot subdwarf was not detected); n = Excluded from the sample because of a "non-subdwarf" classification; AEA = V and (B-V) from Allard et al. (1994AJ....107.1565A) BBL = Nos. 1076 and 1095 had synthetic measurements of b and y only (see Section 2.3); LAN = V and (B-V) from Landolt (1992, Cat. II/183) MEA = Nos. 320 and 1327, Stromgren uvby from Mooney et al., 2000A&A...357..553M TYC = V and (B-V) for No. 234 are converted from Tycho magnitudes (see Section 2.3): VT=10.194, (BT-VT)=+0.111 (ESA, 1997, Hipparcos catalog, I/239) WMG = V and (B-V) from Williams et al. (2001PASP..113..490W)
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Seq Sequential number 6- 79 A74 --- Note Text of the note
Global notes: Note (G1): Not intended to be used as a new designator in the literature, but useful in navigating the KHD (Kilkenney et al., 1988SAAOC..12....1K) catalog and cross-referencing tables 1 and 2.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 16-Oct-2003
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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