J/A+A/493/L27 Parallaxes of 10 ultracool subdwarfs (Schilbach+, 2009)
Trigonometric parallaxes of ten ultracool subdwarfs.
Schilbach E., Roeser S., Scholz R.-D.
<Astron. Astrophys., 493, L27-L30 (2009)>
=2009A&A...493L..27S 2009A&A...493L..27S
ADC_Keywords: Stars, subdwarf ; Parallaxes, trigonometric ;
Photometry, infrared ; Proper motions
Keywords: astrometry - stars: distances - stars: kinematics -
stars: low-mass, brown dwarfs - subdwarfs - solar neighborhood
Abstract:
We measure absolute trigonometric parallaxes and proper motions with
respect to many background galaxies for a sample of ten ultracool
subdwarfs.
Observations were taken in the H-band with the OMEGA2000 camera on the
3.5 m-telescope at Calar Alto, Spain during a time period of
3.5-years. For the first time, the reduction of the astrometric
measurements was carried out directly with respect to background
galaxies. We obtained absolute parallaxes with mean errors ranging
between 1 and 3mas.
Description:
The observations were made with the OMEGA2000 camera on the
3.5m-telescope of the Centro Astronomico Hispano Aleman (CAHA) at
Calar Alto, Spain.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 10 Targets with previously known proper motions,
JHKs photometry and spectral types
table2.dat 135 10 Absolute parallaxes, absolute proper motions and
infrared magnitudes of ultracool Subdwarfs
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See also:
J/AJ/124/1190 : Northern high proper motion stars in DSS (Lepine+, 2002)
J/ApJ/564/421 : Spectra of T dwarfs. I. (Burgasser+, 2002)
J/AJ/125/1598 : New high proper motion stars in the northern sky (Lepine+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Name
16 A1 --- n_Name [*] Individual note on Name (1)
18- 23 F6.3 mag Jmag2 2MASS J magnitude
26- 31 F6.3 mag Hmag2 2MASS H magnitude
34- 39 F6.3 mag Ksmag2 2MASS Ks magnitude
42- 48 A7 --- SpType MK spectral type
50 A1 --- n_SpType [+] Note on SpType (1)
52- 53 I2 --- r_pm Proper motion reference (2)
55- 59 A5 --- r_SpType Spectral type reference (2)
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Note (1): Notes as follows:
* = Lepine et al. (2002, Cat. J/AJ/124/1190) listed an erroneous
position and proper motion for this object
+ = Discovered by Lepine et al. (2003ApJ...591L..49L 2003ApJ...591L..49L) as the first
possible L subdwarf. Cushing & Vacca (2006AJ....131.1797C 2006AJ....131.1797C)
described it as a very peculiar object (M6p/sdM), and Dahn et
al. (2008ApJ...686..548D 2008ApJ...686..548D) recently found it to be an astrometric
binary of the Galactic halo population consisting of a mildly
metal-poor M dwarf and a substellar companion.
Note (2): References as follows:
1 = Burgasser et al. (2002, Cat. J/ApJ/564/421)
2 = Lepine et al. (2003ApJ...591L..49L 2003ApJ...591L..49L)
3 = Scholz et al. (2004A&A...425..519S 2004A&A...425..519S)
4 = Sivarani et al. (2009ApJ...694L.140S 2009ApJ...694L.140S)
5 = Burgasser et al. (2003ApJ...592.1186B 2003ApJ...592.1186B)
6 = Burgasser (2004ApJ...614L..73B 2004ApJ...614L..73B)
7 = Vrba et al. (2004AJ....127.2948V 2004AJ....127.2948V)
8 = Lepine et al. (2003ApJ...585L..69L 2003ApJ...585L..69L)
9 = Lepine et al. (2003, Cat. J/AJ/125/1598)
10 = Scholz et al. (2004A&A...428L..25S 2004A&A...428L..25S)
11 = Burgasser et al. (2007ApJ...657..494B 2007ApJ...657..494B)
12 = Scholz et al. (unpublished, preliminary proper motion solution
based on available SSS and 2MASS data)
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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- 15 A15 --- Name Name
18- 26 F9.6 h RAhr Right ascension in decimal hours (J2000.0) (3)
28- 37 F10.6 deg DEdeg Declination in decimal degrees (J2000.0) (3)
39- 44 F6.2 mas plx Absolute trigonometric parallax
46- 50 F5.2 mas Dplx Applied correction converting the relative
parallaxes to absolute ones (1)
52- 59 F8.2 mas/yr pmRA Absolute proper motion along RA, pmRA*cos(DE)
61- 68 F8.2 mas/yr pmDE Absolute proper motion along DE
70- 75 F6.3 mag Jmag J magnitude
77- 82 F6.3 mag Hmag H magnitude
84- 89 F6.3 mag Ksmag Ks magnitude
91- 95 F5.2 mag KsMAG Absolute Ks magnitude (2)
97- 99 I3 km/s Vt(LSR) Tangential velocity corrected for solar motion
101-104 F4.2 mas e_plx rms uncertainty on plx
106-109 F4.2 mas e_Dplx rms uncertainty on Dplx
111-114 F4.2 mas/yr e_pmRA rms uncertainty on pmRA
116-119 F4.2 mas/yr e_pmDE rms uncertainty on pmDE
121-122 I2 mmag e_Jmag rms uncertainty on Jmag
124 I1 mmag e_Hmag rms uncertainty on Hmag
126-127 I2 mmag e_Ksmag rms uncertainty on Ksmag
129-132 F4.2 mag e_KsMAG rms uncertainty on KsMAG
134-135 I2 km/s e_Vt(LSR) rms uncertainty on Vt(LSR)
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Note (1): (plx(abs)=plx(rel)-Dplx)
Note (2): computed from the corresponding trigonometric parallax and Ks.
Note (3): Barycentric position for epoch J2000.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Apr-2009