J/ApJS/214/17 Orbital monitoring of AstraLux binaries (Janson+, 2014)
Orbital monitoring of the AstraLux large M-dwarf multiplicity sample.
Janson M., Bergfors C., Brandner W., Bonnefoy M., Schlieder J., Kohler R.,
Hormuth F., Henning T., Hippler S.
<Astrophys. J. Suppl. Ser., 214, 17 (2014)>
=2014ApJS..214...17J 2014ApJS..214...17J
ADC_Keywords: Proper motions ; Stars, M-type ; Stars, double and multiple
Keywords: binaries: general; stars: late-type;
techniques: high angular resolution
Abstract:
Orbital monitoring of M-type binaries is essential for constraining
their fundamental properties. This is particularly useful in young
systems, where the extended pre-main-sequence evolution can allow for
precise isochronal dating. Here, we present the continued astrometric
monitoring of the more than 200 binaries of the AstraLux Large
Multiplicity Survey, building both on our previous work, archival
data, and new astrometric data spanning the range of 2010-2012. The
sample is very young overall --all included stars have known X-ray
emission, and a significant fraction (18%) of them have recently also
been identified as members of young moving groups in the solar
neighborhood. We identify ∼30 targets that both have indications of
being young and for which an orbit either has been closed or appears
possible to close in a reasonable time frame (a few years to a few
decades). One of these cases, GJ 4326, is, however, identified as
probably being substantially older than has been implied from its
apparent moving group membership, based on astrometric and isochronal
arguments. With further astrometric monitoring, these targets will
provide a set of empirical isochrones, against which theoretical
isochrones can be calibrated, and which can be used to evaluate the
precise ages of nearby young moving groups.
Description:
In this paper, we perform astrometric follow-up of binaries detected
or confirmed in Bergfors et al. (2010A&A...520A..54B 2010A&A...520A..54B) and Janson et
al. (2012, Cat. J/ApJ/754/44) in order to confirm common proper motion
(CPM) in those cases where this has not yet been accomplished, and to
better constrain their orbital properties.
This work is based primarily on observations acquired over several
years with the AstraLux Norte camera on the 2.2m telescope at Calar
Alto in Spain, and the AstraLux Sur camera on the European Southern
Observatory/New Technology Telescope 3.5m telescope at La Silla in
Chile. The observations acquired specifically within the context of
this program (orbital monitoring of M-dwarf binaries) were taken in
2011 November, 2012 January, and 2012 August with AstraLux Norte, and
2010 October (ESO program ID 086.C-0869(A)) and 2012 January
(088.C-0753(A)) with AstraLux Sur. Additionally, some data taken for
the purpose of our late-type M-dwarf sample (Janson et al.
2014ApJ...789..102J 2014ApJ...789..102J) had a few targets overlapping with targets in
this program, and so the astrometry from those data are included here
as well. All in all, including both science and calibration
observations, this study represents ∼500 new AstraLux observations of
∼10 minutes of telescope time each.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 691 Relative astrometry of all stellar pairs of this
study
table2.dat 54 57 Assessments of orbital motion in systems with
Pest<50yr
pairs.dat 45 224 *List of the 218 stellar pairs of this study, plus
the 6 pairs present only in table2
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Note on pairs.dat: table added at CDS, which summarizes all pairs.
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
I/317 : The PPMXL Catalog (Roeser+ 2010)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/297 : NOMAD Catalog (Zacharias+ 2005)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)
J/AJ/144/64 : Solar neighborhood. XXVIII. companions (Dieterich+, 2012)
J/AJ/143/80 : Low-mass stars of beta Pic & AB Dor groups (Schlieder+, 2012)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/AJ/139/2566 : SLoWPoKES catalog (Dhital+, 2010)
J/A+A/509/A52 : Search for companions with VLT/NACO (Chauvin+, 2010)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)
J/ApJS/161/394 : Low-luminosity companions to white dwarfs (Farihi+, 2005)
J/AJ/130/1680 : LSPM-North proper-motion catalog nearby stars (Lepine+, 2005)
J/A+A/422/1023 : Nearby visual double stars UBVRI phot. (Strigachev+, 2004)
J/AJ/124/3255 : UBV photometry in M15 (van der Marel+, 2002)
J/AJ/123/1023 : Binary star orbits (Seymour+, 2002)
J/A+A/396/933 : Double star measurements at Nice Obs. (Morlet+, 2002)
J/A+A/364/665 : Very low mass stars radial velocities (Segransan+, 2000)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
Byte-by-byte Description of file: pairs.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- 2MASS 2MASS designation (JHHMMSSss+DDMMSSs, II/246;
or JHHMMSSs+DDMMSS for 2MASSI, II/241)
18- 19 A2 --- Comp Components of the system (AB, AC, etc)
21- 23 I3 pc Dist [5/385]? Distance of the system (1)
25- 31 F7.2 mas/yr pmRA [-791/834]? Proper motion along RA (1)
33- 39 F7.2 mas/yr pmDE [-878/388]? Proper motion along Dec (1)
41- 43 A3 --- CPM [YN/U ] common proper motion (CPM)? (U=unclear)
45 A1 --- OM [YNU ] Significant orbital motion (OM)? (1)
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Note (1): value not given for the 6 stars not studied here, but present
in table2; these 6 stars all have "U" (Unknown) orbital motion.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- 2MASS 2MASS designation (JHHMMSSss+DDMMSSs, II/246;
or JHHMMSSs+DDMMSS for 2MASSI, II/241)
18- 19 A2 --- Comp Components of the system (AB, AC, etc)
21- 25 F5.3 arcsec Sep [0.05/9.4] Separation between components ρ
27- 31 F5.3 arcsec e_Sep [0.001/3]? Sep uncertainty
33- 37 F5.1 deg PA Position angle θ
39- 41 F3.1 deg e_PA [0/8]? PA uncertainty
43- 49 F7.2 yr Epoch [1955/2012.9] Epoch of observation
51- 53 I3 pc Dist [5/385] Distance
55- 61 F7.2 mas/yr pmRA [-791/834] Proper motion along RA
63- 69 F7.2 mas/yr pmDE [-878/388] Proper motion along Dec
71- 87 A17 --- Auth Author's reference (1)
89-107 A19 --- BibCode Bibcode's reference (1)
109-111 A3 --- CPM [YN/U ] common proper motion (CPM)? (U=unclear)
113 A1 --- OM [YN ] Significant orbital motion (OM)?
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Note (1): Reference to original publication of the astrometric epoch. The values
in the table will sometimes differ slightly from the values in the reference,
due to an updated astrometric calibration.
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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- 17 A17 --- 2MASS 2MASS designation (JHHMMSSss+DDMMSSs, II/246;
or JHHMMSSs+DDMMSS for 2MASSI, II/241)
18- 19 A2 --- Comp Components of the system (AB, AC, etc)
21- 22 I2 --- Nep [1/12] Number of epochs of observation for
the target
24- 25 I2 yr Per [2/48] Estimated period (Pest) (1)
27- 39 A13 --- Motion Qualitative assessment of the orbital period
from astrometric motion (2)
41- 54 A14 --- Comm Comments (3)
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Note (1): Estimated orbital period from the projected separation and assumed
system mass (Janson et al. 2012, Cat. J/ApJ/754/44).
Note (2): "Rapid" implies a high probability for the orbit to close within 40yr;
other assessments are "Very rapid", "Intermediate", "Slow" or "Unknown".
Note (3): Other comments, noting cases that have only been observed in a
single epoch, have a too short baseline for a useful assessment of
orbital speed to be made, or are members of young moving groups (YMGs).
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 13-Oct-2014