J/A+A/401/959 35 DENIS late-M dwarfs between 10 and 30pc (Phan-Bao+, 2003)
New neighbours. V. 35 DENIS late-M dwarfs between 10 and 30 parsecs.
Phan-Bao N., Crifo F., Delfosse X., Forveille T., Guibert J.,
Borsenberger J., Epchtein N., Fouque P., Simon G., Vetois J.
<Astron. Astrophys., 401, 959-974 (2003)>
=2003A&A...401..959P 2003A&A...401..959P
ADC_Keywords: Stars, nearby ; Stars, M-type ; Photometry, infrared ;
Proper motions
Keywords: astrometry - stars: low mass, brown dwarfs - solar neighbourhood
Abstract:
This paper reports updated results on our systematic mining of the
DENIS database (B/denis) for nearby very cool M-dwarfs (M6V-M8V,
2.0=<I-J=<3.0, photometric distance within 30pc), initiated by
Phan-Bao et al. (2001, Cat. J/A+A/380/590, hereafter Paper I). We
use M dwarfs with well measured parallaxes (HIP, GCTP,...) to
calibrate the DENIS (MI, I-J) colour-luminosity relationship. The
resulting distance error for single dwarfs is about 25%.
Proper motions, as well as B and R magnitudes, were measured on
archive Schmidt plates for those stars in the DENIS database that meet
the photometric selection criteria.
We then eliminate the giants by a Reduced Proper Motion cutoff, which
is significantly more selective than a simple proper motion cutoff. It
greatly reduces the selection bias against low tangential velocity
stars, and results in a nearly complete sample.
Here we present new data for 62 red dwarf candidates selected over
5700 square degrees in the DENIS database. 26 of those originate in
the 2100 square degrees analysed in Paper I, with improved parameters
here, and 36 were found in 3600 additional square degrees. 25 of those
are new nearby dwarfs.
In addition we cross-identified the NLTT and DENIS catalogues to find
15 similar stars, in parts of the sky not yet covered by the
colour-selected search. We present distance and luminosity estimates
for these 15 stars, 10 of which are newly recognized nearby dwarfs. A
similar search in Paper I produced 4 red dwarf candidates, and we have
thus up to now identified a total of 35 new nearby late-M dwarfs.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2a.dat 50 24 High proper motions of the 24 high-PM (pm>0.1"/yr)
late-M dwarfs selected in the 3600 square degree
table2b.dat 50 15 High proper motions of the 15 high-PM (pm>0.1"/yr)
initially selected from the NLTT (I/98)
table2c.dat 49 11 Low proper motions of 11 low-PM (pm<0.1"/yr) probable
late-M dwarfs found in the 5700 square degrees
table3a.dat 114 24 Observational data and reduced proper motions for
the 24 high-PM (from 3600 square degree)
table3b.dat 114 15 Observational data and reduced proper motions for
the 15 high-PM (from NLTT)
table3c.dat 117 11 Observational data and reduced proper motions for
the 11 low-PM with Hi-Himax>1σ
table5a.dat 56 35 Estimated distances and other parameters for the
24 stars of table2a and the 11 stars of table2c
table5b.dat 50 15 Estimated distances and other parameters for the
15 stars of table2b
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See also:
B/denis : The DENIS database (Epchtein+, 1999)
I/87 : LHS Catalogue, 2nd Edition (Luyten 1979)
I/98 : NLTT Catalogue (Luyten, 1979)
J/A+A/380/590 : 30 DENIS late-M dwarfs between 15 and 30pc (Phan-Bao+, 2001)
Byte-by-byte Description of file: table2[abc].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1 A1 --- Type [abc] Type of star (G1)
3- 17 A15 --- DENIS DENIS name (based on J2000 position)
18 A1 --- New [*] *: Not previously known as a high proper
motion star
20- 24 I5 mas/yr pmRA Proper motion in right ascension
27- 31 I5 mas/yr pmDE Proper motion in declination
34- 35 I2 mas/yr e_pmRA ? pmRA error (table2c.dat only)
37- 38 I2 mas/yr e_pmDE ? pmDE error (table2c.dat only)
40- 43 I4 mas/yr pm Total proper motion
46- 49 I4 mas/yr pmL ? Total proper motion (1)
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Note (1): Literature total proper motion, from Luyten catalogues
(Cat. I/98, I/87) when available
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Byte-by-byte Description of file: table3[abc].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Type [abc] Type of star (G1)
3- 17 A15 --- DENIS DENIS name (based on J2000 position)
18 A1 --- n_DENIS Note (1)
20- 29 A10 --- OName Other name (2)
31- 32 I2 h RAh Right ascension (J2000) at Epoch
34- 35 I2 min RAm Right ascension (J2000) at Epoch
37- 41 F5.2 s RAs Right ascension (J2000) at Epoch
44 A1 --- DE- Declination sign (J2000) at Epoch
45- 46 I2 deg DEd Declination (J2000) at Epoch
48- 49 I2 arcmin DEm Declination (J2000) at Epoch
51- 54 F4.1 arcsec DEs Declination (J2000) at Epoch
57- 64 F8.3 yr Epoch DENIS epoch of observation
67- 70 F4.1 mag Bmag ? B magnitude from the SRC-J plate
73- 76 F4.1 mag Rmag ? R magnitude from the plates POSS I, SRC-R
and ESO-R
79- 83 F5.2 mag Imag DENIS I magnitude
86- 89 F4.2 mag I-J DENIS I-J colour index
92- 95 F4.2 mag J-K DENIS J-K colour index
98-101 F4.1 mag H(I) I band reduced proper motion (3)
104-106 F3.1 mag e_H(I) ? H(I) error (only in table3c.dat)
108-110 F3.1 mag H(I)max Maximum I band reduced proper motion (4)
113 A1 --- Ref [a] Reference for proper motion
a: our measurement
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Note (1): J2206227-204706 is previously listed by Gizis et al.,
2000AJ....120.1085G 2000AJ....120.1085G.
Note (2): LP 793-34 is a companion to HIP 57361 (Cat. I/239)
Note (3): Reduced proper motion H(I) for red dwarf candidates, computed
from I magnitude and proper motion as: H = m + 5 + 5logµ
Note (4): Maximum HI for a M giant star (class III) of the same I-J
colour, computed from the (I-J, HImax) relation in the paper
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Byte-by-byte Description of file: table5a.dat table5b.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Type [abc] Type of star (G1)
3- 17 A15 --- DENIS DENIS name
18 A1 --- n_DENIS [*] *: low proper motion red dwarf candidates
21- 25 F5.2 mag IMAG Absolute I band magnitude (1)
28- 31 F4.1 pc DistI Estimated distance from IMAG
34- 37 F4.1 km/s Vt Tangential velocity (computed from D and
proper motion)
40- 43 I4 K Teff Effective temperature (2)
46- 48 A3 --- Ref Reference for previously known distances (3)
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Note (1): Absolute I-band magnitude estimated from the
(I-J, absolute magnitude) relation in the paper
Note (2): Effective temperature estimated from the (I-J, Teff) relation
in the paper
Note (3): References are numbered as follows:
for a previously known trigonometric parallax:
a = Gliese & Jahreiss, 1991, Cat. V/70;
for a spectrophotometric distance:
b = Kirkpatrick et al., 1997AJ....113.1421K 1997AJ....113.1421K
c = Gizis et al., 2000AJ....120.1085G 2000AJ....120.1085G
d = Cruz & Reid, 2002, Cat. J/AJ/123/2828
e = McCaughrean et al., 2002A&A...390L..27M 2002A&A...390L..27M;
or for a photometric distance:
f = Reid & Cruz, 2002, Cat. J/AJ/123/2806
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Global notes:
Note (G1): Type of stars are designated as follows:
a = 24 high proper motions ((pm>0.1"/yr) late-M dwarfs selected in
the 3600 square degree
b = 15 high proper motions ((pm>0.1"/yr) stars initially selected
from the NLTT (I/98)
c = 11 low proper motions (pm<0.1"/yr) probable late-M dwarfs found
in the 5700 square degrees
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Acknowledgements: Phan Bao Ngoc, pbngoc(at)asiaa.sinica.edu.tw
References:
Delfosse et al., Paper I 1999A&A...344..897D 1999A&A...344..897D
Delfosse et al., Paper II 2001A&A...366L..13D 2001A&A...366L..13D
Hambly et al., Paper III 2004A&A...425..997B 2004A&A...425..997B
Phan-Bao et al., Paper IV 2001A&A...380..590P 2001A&A...380..590P, Cat. J/A+A/380/590
(End) Patricia Vannier [CDS] 01-Mar-2005