J/ApJ/789/102 Properties of late M-dwarfs (Janson+, 2014)
The AstraLux multiplicity survey: extension to late M-dwarfs.
Janson M., Bergfors C., Brandner W., Kudryavtseva N., Hormuth F.,
Hippler S., Henning T.
<Astrophys. J., 789, 102 (2014)>
=2014ApJ...789..102J 2014ApJ...789..102J (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, dwarfs ; Stars, M-type ;
Photometry ; Surveys
Keywords: binaries: general - stars: late-type -
techniques: high angular resolution
Abstract:
The distribution of multiplicity among low-mass stars is a key issue
to understanding the formation of stars and brown dwarfs, and recent
surveys have yielded large enough samples of nearby low-mass stars to
study this issue statistically to good accuracy. Previously, we have
presented a multiplicity study of ∼700 early/mid M-type stars observed
with the AstraLux high-resolution Lucky Imaging cameras. Here, we
extend the study of multiplicity in M-type stars through studying 286
nearby mid/late M-type stars, bridging the gap between our previous
study and multiplicity studies of brown dwarfs. Most of the targets
have been observed more than once, allowing us to assess common proper
motion to confirm companionship. We detect 68 confirmed or probable
companions in 66 systems, of which 41 were previously undiscovered.
Detections are made down to the resolution limit of ∼100 mas of the
instrument. The raw multiplicity in the AstraLux sensitivity range is
17.9%, leading to a total multiplicity fraction of 21%-27% depending
on the mass ratio distribution, which is consistent with being flat
down to mass ratios of ∼0.4, but cannot be stringently constrained
below this value. The semi-major axis distribution is well represented
by a log-normal function with µa= 0.78 and σa= 0.47,
which is narrower and peaked at smaller separations than for a
Sun-like sample. This is consistent with a steady decrease in average
semi-major axis from the highest-mass binary stars to the brown dwarf
binaries.
Description:
The targets in this study were selected from the Lepine & Gaidos
(2011, J/AJ/142/138) sample, where stars with a spectral type (SpT)
estimate of M5 or later were selected if they were sufficiently bright
(J ≤ 10.0 mag) and sufficiently far north (>-15°) to be
meaningfully observed with AstraLux Norte. In total, this gave an
input sample of 408 potential targets, of which 286 were actually
observed. All observations in this program were acquired with the
AstraLux Norte camera on the 2.2 m telescope at Calar Alto in Spain.
The 2.2 m telescope is on an equatorial mount. AstraLux uses an
Andor DV887-UVB camera head equipped with a thinned, back-illuminated,
electron-multiplying 512 x 512 pixel monolithic CCD. The CCD is
equipped with two readout registers, one for conventional readout, and
one 536 stage electron multiplication register. Each of the two
registers comes with its own output amplifier. All Lucky Imaging data
were obtained using the electron multiplication mode, and the
associated output amplifier.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 286 General Properties of All Targets Observed in
the Survey
table2.dat 71 131 Astrometric Properties of the Binaries and
Background Stars in the Survey
table3.dat 101 69 Photometric and Physical Properties of the
Binaries in the Survey
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See also:
J/AJ/123/3409 : SDSS M, L, and T dwarfs (Hawley+, 2002)
J/AJ/129/2428 : M dwarf-white dwarf binary systems (Silvestri+, 2005)
J/A+A/503/639 : NIR spectral of M-T dwarfs (Testi, 2009)
J/AJ/137/1 : Proper motions and astrometry of late-type dwarfs
(Faherty+, 2009)
J/AJ/142/138 : All-sky catalog of bright M dwarfs (Lepine+, 2011)
J/AJ/143/10 : 2008-2009 WIYN speckle observations of binaries. VII.
(Horch+, 2012)
J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)
J/ApJ/758/56 : Young M dwarfs within 25pc. II. Kinematics (Shkolnik+, 2012)
J/AJ/145/52 : Abundances of late K and M dwarfs in binary systems
(Mann+, 2013)
J/ApJ/762/88 : Young stellar kinematic group candidate members (Malo+, 2013)
J/MNRAS/429/859 : New companions to nearby low-mass stars (Jodar+, 2013)
J/PASP/125/809 : New nearby M, L, and T dwarfs (Thompson+, 2013)
J/A+A/577/A128 : CARMENES input catalogue of M dwarfs. I
(Alonso-Floriano+, 2015)
J/AJ/150/42 : Catalog of 2612 M dwarfs from LAMOST (Zhong+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- ID ID from Lepine (G1)
14- 15 I2 h RAh Hour of Right Ascension (J2000)
17- 18 I2 min RAm Minute of Right Ascension (J2000)
20- 25 F6.3 s RAs Second of Right Ascension (J2000)
27 A1 --- DE- Sign of the Declination (J2000)
28- 29 I2 deg DEd Degree of Declination (J2000)
31- 32 I2 arcmin DEm Minute of Declination (J2000)
34- 38 F5.2 arcsec DEs Second of Declination (J2000)
40- 44 I5 mas/yr pmRA Proper motion in RA
46- 50 I5 mas/yr pmDE Proper motion in DE
52- 56 F5.1 mas plx Parallax
58- 61 F4.1 mas e_plx rms uncertainty on plx
63- 66 A4 --- r_plx Reference for plx in refs.dat file
68- 71 A4 --- SpType Spectral type (1)
73- 77 A5 --- r_SpType Reference for spectral type in refs.dat file
79- 82 F4.2 mag Jmag J magnitude
84- 88 A5 --- Mult Multiplicity flag (2)
90 A1 --- ND [YN-] Flag for whether the companion is a new
discovery (Y) or not (N)
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Note (1): lower case notation implies a color-based SpT estimation which may
be biased, see text.
Note (2): Multiplicity flag as follows:
S = single, as far as is known.
M = multiple within the AstraLux sensitivity range.
C = a known companion exists in the literature but is too close in for
AstraLux
W = a known companion exists outside of the AstraLux completeness range.
O = an object is observed in the AstraLux image, but is outside of the
completeness range.
BG = one or more suspected or confirmed background objects are observed in the
images. See individual notes for detailed comments.
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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- 12 A12 --- ID ID from Lepine (G1)
14- 23 A10 --- OtherID Other ID
25- 28 A4 --- Pair Pair
30- 34 F5.3 arcsec rho Separation angle
36- 40 F5.3 arcsec e_rho rms uncertainty on rho
42- 46 F5.1 deg theta Position angle
48- 50 F3.1 deg e_theta rms uncertainty on theta
51 A1 --- n_theta [d] Note on theta (4)
53- 59 F7.2 yr Epoch Epoch
61- 63 A3 --- Ref Source of the astrometry at the given epoch.
Only one archival epoch listed per target (1)
65- 67 A3 --- CPM Flag for common proper motion (2)
69- 71 A3 --- OM Flag for orbital motion (3)
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Note (1): References as follows :
TP = this paper
WDS = Washington Double Star Catalog, Mason et al.
(2001AJ....122.3466M 2001AJ....122.3466M, Cat.B/wds)
M01 = McCarthy et al. (2001AJ....121.3259M 2001AJ....121.3259M)
B04 = Beuzit et al. (2004A&A...425..997B 2004A&A...425..997B); uniform errors assumed
M06 = Montagnier et al. (2006A&A...460L..19M 2006A&A...460L..19M)
P06 = Pravdo et al. (2006ApJ...649..389P 2006ApJ...649..389P)
D07 = Daemgen et al. (2007ApJ...654..558D 2007ApJ...654..558D)
L08 = Law et al. (2008MNRAS.384..150L 2008MNRAS.384..150L)
D10 = Dupuy et al. (2010ApJ...721.1725D 2010ApJ...721.1725D) orbital analysis; original data point
from Montagnier et al. (2006A&A...460L..19M 2006A&A...460L..19M)
H12 = Horch et al. (2012, J/AJ/143/10)
J12 = Janson et al. (2012, J/ApJ/754/44)
J13 = Jodar et al. (2013, J/MNRAS/429/859)
Note (2): Flag for common proper motion (evaluated between the first and last
listed epochs), as follows :
Y = yes
N = no
I = inferred
Note (3): Flag for orbital motion (between the first and last listed epochs),
as follows :
Y = yes
N = no
U = unclear
BG = background
Note (4): d for quoted angle assumes a phase shift, see individual note for the
target.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- ID ID from Lepine (G1)
14- 23 A10 --- OtherID Other ID
25- 28 A4 --- Pair Pair
30- 33 F4.2 mag Dz'mag Magnitude difference in z' band
35- 38 F4.2 mag e_Dz'mag rms uncertainty on Dz'mag
40- 43 F4.2 mag Di'mag ?=- Magnitude difference in i' band
45- 48 F4.2 mag e_Di'mag ? rms uncertainty on Di'mag
50- 53 I4 Myr tau-low Lower age estimation
55- 59 I5 Myr tau-high Upper age estimation
61- 64 A4 --- Ref Basis for the age estimation (1)
66- 69 F4.2 Msun massA Mass of A component
71- 74 F4.2 Msun e_massA rms uncertainty on massA
76- 79 F4.2 Msun massB Mass of B component
81- 84 F4.2 Msun e_massB rms uncertainty on massB
86- 89 F4.2 --- q Mass ratio
91- 94 F4.2 --- e_q rms uncertainty on q
96- 99 F4.1 AU aest Major axis estimation
101 A1 --- SC [YN-] Flag for whether targets is
statistically clean (Y) or not (N)
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Note (1): References as follows :
Sc12 = Member of AB Dor of β Pic moving group according to
Schlieder et al. (2012AJ....144..109S 2012AJ....144..109S)
Sh12 = Estimated age in Shkolnik et al. (2012, J/ApJ/758/56)
M13 = Member of a young moving group according to Malo et al.
(2013, J/ApJ/762/88)
VY = Assumed very young based on high X-ray flux
(as listed in Lepine & Gaidos 2011, J/AJ/142/138)
MY = Assumed moderately young based on moderate X-ray flux
NY = Assumed not young based on lack of detectable X-ray flux
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Note (G1): From Lepine & Gaidos (2011AJ....142..138L 2011AJ....142..138L), IHHMMm+DDMMN,
PM JHHMMm+DDMMN in Simbad
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 07-Mar-2017