J/ApJ/582/1011 Revised NLTT Catalog (Salim+, 2003)
Improved astrometry and photometry for the Luyten catalog.
II. Faint stars and the revised catalog.
Salim S., Gould A.
<Astrophys. J. 582, 1011 (2003)>
=2003ApJ...582.1011S 2003ApJ...582.1011S
ADC_Keywords: Proper motions; Stars, high-velocity
Keywords: astrometry - catalogs - methods: statistical
Abstract:
We complete construction of a catalog containing improved astrometry
and new optical/infrared photometry for the vast majority of NLTT
stars lying in the overlap of regions covered by POSS I and by the
second incremental Two Micron All Sky Survey (2MASS) release,
approximately 44% of the sky. The epoch 2000 positions are typically
accurate to 130mas, the proper motions to 5.5mas/yr, and the V-J
colors to 0.25mag. Relative proper motions of binary components are
measured to 3mas/yr. The false-identification rate is ∼1% for
11≤V≤18 and substantially less at brighter magnitudes. These
improvements permit the construction of a reduced proper-motion
diagram that, for the first time, allows one to classify NLTT stars
into main-sequence (MS) stars, subdwarfs (SDs), and white dwarfs
(WDs). We in turn use this diagram to analyze the properties of both
our catalog and the NLTT catalog on which it is based. In sharp
contrast to popular belief, we find that NLTT incompleteness in the
plane is almost completely concentrated in MS stars, and that SDs and
WDs are detected almost uniformly over the sky δ>-33°. Our
catalog will therefore provide a powerful tool to probe these
populations statistically, as well as to reliably identify individual
SDs and WDs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 288 36085 Revised NLTT Catalog (Dec>-33°)
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See also:
I/98 : NLTT Catalogue (Luyten, 1979)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
I/243 : The PMM USNO-A1.0 Catalogue (Monet 1997)
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
I/276 : Tycho Double Star Catalogue (TDSC) (Fabricius+ 2002)
I/279 : Revised Luyten Half-Second Catalogue (Bakos+ 2002)
I/220 : The HST Guide Star Catalog, Version 1.1 (Lasker+ 1992)
I/254 : The HST Guide Star Catalog, Version 1.2 (Lasker+ 1996)
I/255 : The HST Guide Star Catalog, Version GSC-ACT (Lasker+ 1996-99)
I/271 : The Guide Star Catalog, Version 2.2 (GSC2.2) (STScI, 2001)
II/241 : The 2MASS database, Intermediate Release (IPAC/UMass, 2000)
J/AJ/98/1693 : UBVRI photometry of NLTT stars (Ryan 1989)
J/AJ/123/2806 : Nearby stars in the NLTT catalogue (Reid+, 2002)
J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002)
J/AJ/123/2828 : Spectroscopy of northern NLTT stars (Cruz+, 2002)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- NLTT [1/58847] The NLTT number (1)
6 A1 --- m_NLTT [ABC] The NLTT binary component
8- 17 F10.6 deg RAdeg Right ascension (decimal deg) (J2000) (2)
19- 28 F10.6 deg DEdeg Declination (decimal deg) (J2000) (2)
30- 36 F7.4 arcsec/yr pmRA Proper motion in right ascension
38- 44 F7.4 arcsec/yr pmDE Proper motion in declination
46- 51 F6.4 arcsec/yr e_pmRA Error in pmRA
53- 58 F6.4 arcsec/yr e_pmDE Error in pmDE
60- 64 F5.2 mag Vmag The V band magnitude (3)
66- 70 F5.2 mag V-J ?=-9 The (V-J) color (4)
72- 74 I3 --- ICode 3-digits source-of-information code (5)
76- 84 F9.5 deg RANdeg NLTT Right Ascension (J2000) (2)
86- 94 F9.5 deg DENdeg NLTT Declination (J2000) (2)
96-102 F7.4 arcsec/yr pmRAN NLTT Proper motion in right ascension
104-110 F7.4 arcsec/yr pmDEN NLTT Proper motion in declination
112-115 F4.1 mag BmagN ?=-9 NLTT B band photographic magnitude
117-120 F4.1 mag RmagN ?=-9 NLTT R band photographic magnitude
122-127 I6 --- HIP The Hipparcos number (6)
129-140 A12 --- ID Identifier from TDSC, Tycho-2, or
Starnet (7)
142-150 I9 10-2arcsec RAUs ?=0 USNO Right Ascension in arcsec/100
(J2000) (8)
152-160 I9 10-2arcsec DEUs ?=0 USNO South Polar Distance in
arcsec/100 (J2000) (8)
162-165 F4.1 mag BmagU USNO-A1 or USNO-A2 B band magnitude
167-170 F4.1 mag RmagU USNO-A1 or USNO-A2 R band magnitude
172-179 F8.3 yr EpochU The epoch for RAUs and DEUs
181-183 I3 --- CodeU USNO 3-digit search-history code (9)
185-193 F9.5 deg RA2deg 2MASS right ascension (J2000) (10)
195-203 F9.5 deg DE2deg 2MASS Declination (J2000) (10)
205-210 F6.3 mag Jmag ?=-9 The 2MASS J band magnitude (10)
212-217 F6.3 mag Hmag ?=-9 The 2MASS H band magnitude (10)
219-224 F6.3 mag Ksmag ?=-9 The 2MASS Ks band magnitude (10)
226-233 F8.3 yr Epoch2 ?=0 The epoch for RAdeg2 and DEdeg2
235 I1 --- BInd The binarity indicator (11)
237-241 I5 --- BinN ?=0 The NLTT number of binary companion
243-248 F6.1 arcsec SepN ?=-1 The NLTT estimated separation
250-254 F5.1 deg PAN ?=-1 The NLTT estimated position angle
256-261 F6.1 arcsec Sep Our estimated separation (12)
263-267 F5.1 deg PA Our estimated position angle (12)
269 I1 --- SubCode The subcatalog code (13)
271-282 A12 --- OName Name as given in the original NLTT (14)
284-288 A5 --- LHS The LHS number (15)
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Note (1): Corresponds to record number in original electronic catalog I/98.
Bakos et al. (2002, BSN, Cat. I/279) have obtained new astrometry
for the LHS catalog (Luyten, 1979, Cat. I/87), which contains 4470
high proper motion stars, all but three of which are also listed in
NLTT. One of the three, LHS 3989, may not be real.
We list the other two, LHS 2397a and LHS 325a, as additional entries
at the end of NLTT ("NLTT 58846" and "NLTT 58847"). LHS also contains
seven duplicate entries, which we list (LHS1, LHS2; NLTT):
(28, 201: 14386), (1611, 5086; 12036), (2785, 2786; 35066),
(5217a, 6235; 31043), (5215a, 6231; 30597), (6035, 6036; 6226), and
(6132, 75125; 18194). In addition, there is one null entry, LHS 6219.
Note (2): Epoch 2000.
Note (3): Refers to the Johnson V entry for Hipparcos I/239,
Tycho V for Tycho-2 I/259 and TDSC I/276, Guide-star catalog R
for Starnet, and an interpolation of photographic magnitudes for
USNO-A1 I/243 and USNO-A2 I/252. See text for more detail
Note (4): Note that if no J band photometry is available (whether
because of saturation, faintness, or the star being in an area outside
the second incremental 2MASS release) V-J is given as -9.
Note (5): The three digits of the source code refer to the sources of the
position, proper motion, and V photometry. More specifically, ``555''
means 2MASS based position, USNO based V photometry, and USNO/2MASS
based proper motion.
1 = Hipparcos I/239;
2 = Tycho-2 I/259;
3 = Tycho Double Star Catalog (TDSC, Fabricius et al., 2002, I/276)
4 = Starnet;
5 = USNO/2MASS I/243, I/252 <B/2mass>;
6 = NLTT I/98;
7 = USNO I/243, I/252 (for position) or common proper motion
companion (for proper motion).
Note (6): 0 if not in Hipparcos.
Note (7): When the position comes from Hipparcos, 2MASS, or USNO, or NLTT,
blank is entered in this field with one exception: when a Starnet
measurement has been superseded by a 2MASS measurement, the Starnet
identifier has been retained for ease of recovery of this source. It
can easily be determined that the summary information comes from 2MASS
because the first digit in field 11 will be a ``5''.
Note (8): The Integer RA and DE together serve as a unique USNO identifier
since that is the form RA and DE are given in the original USNO-A1
I/243 and USNO-A2 I/252 releases. They can also be converted into
degree α and δ (at the USNO epoch) using the formulae:
α = (RAUs)/360000, δ = (DEUs)/360000 - 90.
Note (9): 3-digits search history code:
1. The first digit tells which USNO catalog the entry is from:
1 = USNO-A1 I/243, 2 = USNO-A2 I/252.
2. The second tells whether the USNO source was found in the
rectangle (1) or the circle (2).
3. The third tells whether it was a unique match (1), or had to be
resolved by hand from among several possible matches (2).
If there is no USNO information, all of these fields are set to zero.
If the USNO star was identified after our normal rectangle and circle
searches, the second and third digits are set to zero.
Note (10): If no 2MASS data are available, all fields are replaced by zeros.
If there are 2MASS data, but not for a particular magnitude
measurement, that value is replaced by -9.
Note (11): 0 means NLTT does not regard this as a binary.
Otherwise, it is a NLTT binary and the indicator is set according to
whether the companion is (2) or is not (1) in our catalog.
Note (12): Our estimates come from the difference of the 2000 positions
of the two stars. In cases for which the companion is not in our
catalog, the fields with ``our'' separation and position angle are
replaced by values found from the difference of the NLTT coordinates.
Note (13): Used in the program that assembles the catalog from the
various subcatalogs that are described in Paper I and in Sections 3
and 5 of this paper. It is useful mainly to us, but for completeness:
1 = PPM+2MASS I/146, I/193, <B/2mass>
2 = USNO/2MASS I/243, I/252, <B/2mass>
3 = CPM (common proper motion)
4 = not used
5 = 2MASS-only, <B/2mass>
6 = PPM (no 2MASS), I/146, I/193
7 = Annulus match
8 = USNO-only, I/243, I/252
9 = BSN, Bakos et al. (2002, Cat. I/279)
Note (14): Left blank when Luyten did not assign a name.
* = NLTT note exist.
Note (15): For the seven stars that have duplicate LHS entries, the
smaller-numbered name is given.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 21-Feb-2003