J/AJ/155/252 Astrometry & photometry of dwarf carbon stars (Harris+, 2018)
Distances of dwarf carbon stars.
Harris H.C., Dahn C.C., Subasavage J.P., Munn J.A., Canzian B.J.,
Levine S.E., Monet A.B., Pier J.R., Stone R.C., Tilleman T.M.,
Hartkopf W.I.
<Astron. J., 155, 252 (2018)>
=2018AJ....155..252H 2018AJ....155..252H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, dwarfs ; Stars, carbon ; Proper motions ;
Parallaxes, trigonometric ; Photometry, UBVRIJKLMNH ;
Stars, double and multiple
Keywords: astrometry - parallaxes - proper motions - stars: carbon -
stars: distances
Abstract:
Parallaxes are presented for a sample of 20 nearby dwarf carbon stars.
The inferred luminosities cover almost two orders of magnitude. Their
absolute magnitudes and tangential velocities confirm prior expectations
that some originate in the Galactic disk, although more than half of this
sample are halo stars. Three stars are found to be astrometric binaries,
and orbital elements are determined; their semimajor axes are 1-3 au,
consistent with the size of an AGB mass-transfer donor star.
Description:
The sample of 20 dwarf carbon (dC) stars in this paper consists of 13
targets taken from the Sloan Digital Sky Survey (SDSS; Fukugita et al.
1996AJ....111.1748F 1996AJ....111.1748F; Gunn et al. 1998AJ....116.3040G 1998AJ....116.3040G, 2006AJ....131.2332G 2006AJ....131.2332G;
York et al. 2000AJ....120.1579Y 2000AJ....120.1579Y) and seven targets from other papers in
the literature.
Images have been taken with the U.S. Naval Observatory's (USNO) 1.55 m
Strand Astrometric Reflecting Telescope in Flagstaff, AZ. Descriptions
of the telescope, the CCD cameras and filters used here, and the observing
and processing procedures are given by Monet et al. (1992, J/AJ/103/638)
and Dahn et al. (2017, J/AJ/154/147). The astrometric results are given
in Table 1.
Photometry of most of the target stars and their surrounding reference
stars was obtained with the USNO 1.0 and 1.55 m telescopes using
Johnson-Cousins BVI filters. These data were used in the astrometric
processing above to correct for differential color refraction (DCR).
For those fields lacking BVI photometry, gri data from the SDSS database
were transformed to BVI using the relations of Ivezic et al. (2007,
J/AJ/134/973) and then used for the DCR corrections. Photometric data for
the 20 dC target stars is given in Table 2 including JHKS from 2MASS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 159 20 Astrometric results
table2.dat 90 20 Photometric results
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/AJ/103/638 : USNO Photographic Parallaxes. I. (Monet+, 1992)
J/AJ/124/1651 : Faint high-latitude carbon stars SDSS photometry
(Margon+, 2002)
J/AJ/127/2838 : Faint high-latitude carbon stars SDSS photometry
(Downes+, 2004)
J/AJ/134/973 : SDSS Stripe 82 star catalogs (Ivezic+, 2007)
J/ApJ/765/12 : Carbon stars and DQ white dwarfs from SDSS-DR7+DR8
(Green, 2013)
J/ApJS/224/36 : The AllWISE motion survey (AllWISE2) (Kirkpatrick+, 2016)
J/AJ/154/147 : Astrometry&photometry for late-type dwarfs&subdwarfs
(Dahn+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss-DDMMSSs)
18- 41 A24 --- AName Alternate name(s) (1)
43- 44 I2 h RAh 2MASS Hour of Right Ascension (J2000)
46- 47 I2 min RAm 2MASS Minute of Right Ascension (J2000)
49- 52 F4.1 s RAs 2MASS Second of Right Ascension (J2000)
54 A1 --- DE- 2MASS Sign of the Declination (J2000)
55- 56 I2 deg DEd 2MASS Degree of Declination (J2000)
58- 59 I2 arcmin DEm 2MASS Arcminute of Declination (J2000)
61- 62 I2 arcsec DEs 2MASS Arcsecond of Declination (J2000)
64- 68 A5 --- Camera Camera used for observations (TEK2K or EEV24)
70- 73 A4 --- Filter Filter used for observations (I-2 or A2-1)
75- 77 I3 --- Nfr [37/293] Number of frames
79- 81 I3 --- Nights [30/231] Number of nights
83- 84 I2 --- Nst [6/21] Number of reference stars
86- 92 F7.2 yr Date1 First date of coverage
94-100 F7.2 yr Date2 Last date of coverage
102-106 F5.2 yr Nyr [4.16/14.41] Number of years of coverage
108-112 F5.2 mas plxrel [0.83/11.53] Relative parallax
114-117 F4.2 mas e_plxrel [0.15/0.63] Error in plxrel
119-123 F5.1 mas/yr pmrel [41.1/765.7] Relative total proper motion
125-127 F3.1 mas/yr e_pmrel [0.1/0.3] Error in pmrel
129-133 F5.1 deg PArel [89.8/325.8] Position angle of relative proper
motion
135-137 F3.1 deg e_PArel [0.2/0.3] Error in PA
139-143 F5.2 mas plxabs [1.66/12.77] Absolute parallax
145-148 F4.2 mas e_plxabs [0.16/0.63] Error in plxabs
150-152 I3 km/s Vtan [44/583] Tangential velocity
154-155 I2 km/s e_Vtan [3/81] Error in Vtan
157 I1 --- Pop [1/4] Estimated Galactic population membership
(2)
159 I1 --- Note [1/4]? Additional note (3)
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Note (1): Usually the name by which the star was first identified as a carbon
star.
Note (2): Galactic population membership as follows:
1 = Disk;
2 = Halo;
3 = Intermediate;
4 = Contradictory.
Note (3): Note as follows:
1 = Hints of a possible very low amplitude perturbation not confirmed;
2 = No evidence seen corresponding to the 245 day radial velocity period
reported by Dearborn et al. (1986ApJ...300..314D 1986ApJ...300..314D);
3 = Tabulated astrometry after removal of the perturbation discussed in
Section 2.4 of the paper;
4 = This is the common proper motion companion to 2MASS J14572616+2341227
(LSPM J1457+2341S) for which an absolute parallax of 5.77±1.48 mas
was reported in Dahn et al. (2017, J/AJ/154/147). Additional observations
further support the physical nature of the pair. The weighted mean
astrometric results for the pair are reported here. Kirkpatrick et al.
(2016, J/ApJS/224/36) reported evidence for a third component based on the
ALLWISE motion survey.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss-DDMMSSs)
18- 22 F5.2 mag Bmag [15.64/19.95]? The B band magnitude
24- 27 F4.2 mag e_Bmag [0.01/0.15]? Error in Bmag
29- 33 F5.2 mag Vmag [13.89/18.29] The V band magnitude
35- 38 F4.2 mag e_Vmag [0.01/0.1] Error in Vmag
40- 44 F5.2 mag Imag [12.33/16.49] The I band magnitude
46- 49 F4.2 mag e_Imag [0.01/0.1] Error in Imag
51 I1 --- r_BVI [1/3] Source of BVI photometry (1)
53- 58 F6.3 mag Jmag [11.47/15.609] 2MASS J band magnitude
60- 64 F5.3 mag e_Jmag [0.021/0.054] Error in Jmag
66- 71 F6.3 mag Hmag [10.844/15.053] 2MASS H band magnitude
73- 77 F5.3 mag e_Hmag [0.021/0.071] Error in Hmag
79- 84 F6.3 mag Ksmag [10.48/14.764] 2MASS KS band magnitude
86- 90 F5.3 mag e_Ksmag [0.016/0.092] Error in Ksmag
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Note (1): Source of BVI photometry as follows:
1 = BVI from CCD measures on the NOFS 1.0 m telescope with estimated errors
inflated to allow for significant differences between the spectral energy
distributions of dwarf carbon stars and the photometric standard stars
employed;
2 = BVI from 17 independent measures on the NOFS 1.55 m telescope employing
a single channel photoelectric photometer with instrumental response
bandpasses well matched to the standard system;
3 = BVI from SDSS gri data transformed to the Johnson-Cousins system via the
relations presented by Ivezic et al. (2007, J/AJ/134/973, Table 7)
and estimated errors inflated to allow for significant instrument bandpass
differences.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 21-Dec-2018