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III/123B        Dwarf K and M stars of small proper motion     (Stephenson 1986)

Dwarf K And M Stars of small proper motion found in a Large Spectroscopic Survey Stephenson C.B. <Astron. J. 91, 144 (1986)> =1986AJ.....91..144S
ADC_Keywords: Stars, dwarfs ; Stars, late-type ; Description (Abstract): More than 2000 candidates for K and M dwarf status, generally having proper motions that are either unknown or less than 0.2" per annum, have been identified in an objective-prism survey covering the entire sky north of declination -25deg and more than 10deg from the galactic plane. More than 95% have no previous indication that they are dwarfs. Several dozen appear to be visual double stars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file catalog.dat 80 2201 The original catalogue of 2201 stars notes.dat 80 185 Individual notes of the original catalog stkm1.dat 124 2214 The catalog revisited (B. Skiff, May 2006; see the "Revision" section below)
See also: J/AJ/80/972 : Dwarf K and M stars at low latitudes (Stephenson+, 1975) Byte-by-byte Description of file: catalog.dat
Bytes Format Units Label Explanations
2- 5 I4 --- Star [1/2201]+ Star number (StKM 1-NNNN in Simbad) 6 A1 --- n_Star [*] The asterisk indicates a note detailed in file 'notes.dat' 8- 9 I2 h RAh Right ascension 1900 (hours) 11- 12 I2 min RAm Right ascension 1900 (minutes) 14- 17 F4.1 s RAs Right ascension 1900 (seconds) 20 A1 --- DE- Declination 1900 (sign) 21- 22 I2 deg DEd Declination 1900 (degrees) 24- 25 I2 arcmin DEm Declination 1900 (minutes) 27- 28 I2 arcsec DEs Declination 1900 (seconds) 31- 34 F4.1 mag Pmag Stellar photographic magnitude 36- 40 A5 --- Sp Spectral type 42- 80 A39 --- Names Names from other lists
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Star [1/2201]+= Star number 5 A1 --- --- [.] 7- 80 A74 --- Text Text of note
Byte-by-byte Description of file: stkm1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- Star [1/2201]+= Star number (StKM 1-NNNN in Simbad) 5- 6 A2 --- m_Star [abc ] Multiplicity 9- 10 I2 h RAh ? Right Ascension J2000 (hours) 12- 13 I2 min RAm ? Right Ascension J2000 (minutes) 15- 19 F5.2 s RAs ? Right Ascension J2000 (seconds) 21 A1 --- DE- ? Declination J2000 (sign) 22- 23 I2 deg DEd ? Declination J2000 (degrees) 25- 26 I2 arcmin DEm ? Declination J2000 (minutes) 28- 31 F4.1 arcsec DEs ? Declination J2000 (seconds) 33 A1 --- rPos [UTMbCBLDS] Source of position (1) 35- 42 I8 --- UCAC2 ? Designation in UCAC2 (I/289) 44- 54 A11 --- Tycho-2 Designation in Tycho-2 (I/259) 56- 59 F4.1 mag Vmag Stellar V magnitude mainly from CMC11 (I/256) 61- 65 A5 --- Sp Spectral type (2) 68-124 A57 --- Notes Additional identifications and remarks
Note (1): the letter indicates the origin of the position, as follows: B = Bordeaux meridian circle PM2000 (2006A&A...448.1235D, Cat. I/300) b = USNO-B1.0 (2003AJ....125..984M, Cat. I/284) C = Carlsberg CMC11 (1999, Cat. I/256) L = Lepine LSPM (2005AJ....129.1483L, Cat. I/298) M = 2MASS (2006AJ....131.1163S, Cat. II/246) S = SDSS DR3 (2005AJ....129.1755A, Cat. II/259 T = Tycho-2 (2000A&A...357..367H, Cat. I/259) U = UCAC2 (2004AJ....127.3043Z, Cat. I/289) Note (2): About halt of the stars are actually ordinary giants (see the "revision"(?) section below). The luminosity class 'V' was added only when Stephenson specifically remarked on strong MgH + MgI 'b' and/or NaD lines in the spectra.
Revision of the catalog by Brian Skiff (May 2006): A number of problems in the original list was noticed for the incorporation of this list into the catalogue (III/233) of spectral classifications. The coordinates are from four sources: -- original printed catalogue: numerous modest errors or typos in coords and DM numbers; several stars lost evidently from gross coordinate errors -- note especially a poorly-reduced field near 19h45m/+00. -- VizieR on-line file: some typos, mainly transposition of digits -- SIMBAD database: various errors, coordinates evidently keyed-in independently of the VizieR file since the errors are different -- Weis (1991AJ....102.1795W) semi-accurate coordinates The original catalog was first matched against UCAC2 and Tycho-2 to get positions at both epoch and equinox J2000 if possible. Some stars do not appear in these catalogues, so coordinates were obtained from other reliable sources as specified below, with preference for those showing proper motion. For stars with modest position errors I was able to use the UBVRI(k) photometry of Weis (1991AJ....102.1795W) and 2MASS or other colors to identify likely candidates. In several cases Weis has suggested more distant candidates, and most of these seem to be likely identifications. (Weis's photometry is essential with regard to the Stephenson stars.) Using the revised coordinates, I then matched the list in VizieR against: HD and HDE, BD, CD, CPD, PPM Supplement, Dearborn, GCVS v4.2, IRAS, MSX, and the Fabricius et al. Tycho double-stars catalogue. Many HD/DM names were overlooked by Stephenson. Useful IDs were added to each entry, double stars flagged, etc. I also searched SIMBAD at the position of every star using a 3' search radius for multiple entries that should be linked. There are a lot of them, and they are indicated in the remarks if not implicit in the Tycho-2 identifications. Double stars: There are several "new" common-motion pairs (not in WDS) amongst these objects. Some were reported first by Stephenson, but many more were noticed by Weis, and some are identified here via their common motions and colors. Some pairs for instance don't have catalogued motions for both components, but the link is simply from there being no change in orientation between (say) DSS1 and 2MASS images despite significant motion on the sky. There are probably many more of these to be found in the list. Where Stephenson shows separate spectral types for the components of pairs (or neighbouring field stars) I have listed the stars separately. Photometry: Stephenson estimated V magnitudes by eye with only a single global calibration of the plates. I have replaced them with standard V from: Weis, ASAS-3, CMC, Tycho-2, TASS MkIII, TASS MkIV (in descending order of preference). A few stars have photoelectric data from other sources shown in SIMBAD as well. Nearly all the stars were observed by the Carlsberg meridian circle, and comparison of its V magnitudes against Weis and ASAS-3 showed they were reliable at the ∼0.1 mag level. The main goal here was to remove Stephenson's systematic errors, not to provide precise magnitudes. It is remarkable how good Stephenson's estimates are, but they indeed show various systematic effects: west of about 17h RA (i.e. the first two-thirds of the list) the magnitudes tend to be too faint overall by several tenths (i.e. a zero-point error), and are especially so at the faint end (i.e. a scale error for faint stars): stars with mv > ∼12.5 are actually about a full magnitude brighter. East of 17h RA, Stephenson's estimates are scattered but the zero-point is about right; the scale error for the faint stars persists, however. Spectral types: Because of the low dispersion of the objective-prism plates, Stephenson often showed the types with a hyphen, e.g. K4-5, to indicate the range of uncertainty. In the file "stkm1.dat" these uncertain types are shown in Houk-style 'slash' notation e.g. K4/5. Stephenson occasionally appended a lower-case 'r' to the types to indicate that the spectrum appeared reddened. In SIMBAD these stars are given with ellipsis following the temperature type. Since the 'r' is uncommon usage, I have moved them to the remarks and spell out the word. Giants versus dwarfs: As Ed Weis' photometry showed, as many as half the stars in the list are ordinary giants, not_dwarfs, particularly among the earlier K types. This was evident to me also from 2MASS J-K colors, often larger than 1.0, which simply cannot apply to K and early-M dwarfs. Stephenson found roughly double the expected space density of dwarf stars because of this. One can compare the color/spectral-type relationships tabulated, for instance, by Bessell & Brett (1988PASP..100.1134B) or by Sandy Leggett (1992ApJS...82..351L) to see that this is the case. The U-B colors measured by Weis are especially diagnostic when compared with (say) R-I or other temperature indicator toward the red. With simple UBV data for stars with B-V > 1.2, U-B is always less than B-V among dwarfs, and larger than B-V for giants. Weis shows similar two-color relations in his paper. In the "stkm1.dat" file, the luminosity class V was added to the types only when Stephenson specifically remarked on strong MgH+MgI'b' and/or Na D lines in the spectra. The rest are left without luminosity class. The new coordinates and additional information is assembled in the "stkm1.dat" file. For pairs considered single by Stephenson, coordinates for the mid-point are given rounded to 1" precision. Magnitudes are for the combined light of such pairs. In the remarks, stars with proper motion greater than 0".15/yr are flagged as 'lg pm' (large proper motion). Double stars are described by separation, and components by compass directions; 'cpm' = common proper motion. All of Stephenson's comments related to the spectra or to companions are included. The stars that could not be recovered ('not found') are shown without coordinates -- there is certainly no suitable star within several arcminutes radius of the nominal place, and given the ubiquity of stars of similar color, there is no ready way to find them without looking at the original plate material. Historical Notes: * Originally keypunched at CDS * 15-Mar-1995: added file 'notes', the '*' flag in file 'catalog'; several clerical errors corrected in the course of the standardisation. * 07-May-2006: file "stkm1.dat" prepared by Brian Skiff added. (see th "Revision" section above)
(End) Francois Ochsenbein [CDS], Brian Skiff [Lowell Obs.] 07-May-2006
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