J/A+A/650/A190 Wide companions to M and L subdwarfs (Gonzalez-Payo+, 2021)
Wide companions to M and L subdwarfs with Gaia and the Virtual Observatory.
Gonzalez-Payo J., Cortes-Contreras M., Lodieu N., Solano E., Zhang Z.H.,
Galvez-Ortiz M.-C.
<Astron. Astrophys. 650, A190 (2021)>
=2021A&A...650A.190G 2021A&A...650A.190G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, subdwarf
Keywords: techniques: photometric - astrometry - surveys -
virtual observatory tools - stars: low-mass
Abstract:
The aim of the project is to identify wide common proper motion
companions to a sample of spectroscopically confirmed M and L
metal-poor dwarfs (also known as subdwarfs) to investigate the impact
of metallicity on the binary fraction of low-mass metal-poor binaries
and to improve the determination of their metallicity from the
higher-mass binary.
We made use of Virtual Observatory tools and large-scale public
surveys to look in Gaia for common proper motion companions to a
well-defined sample of ultracool subdwarfs with spectral types later
than M5 and metallicities below or equal to ∼0.5dex. We collected
low-resolution optical spectroscopy for our best system, which is a
binary composed of one sdM1.5 subdwarf and one sdM5.5 subdwarf located
at ∼1360au, and for another two likely systems separated by more
than 115000au.
We confirm one wide companion to an M subdwarf, and infer a
multiplicity for M subdwarfs (sdMs) of 1.0-1.0+2.0% for projected
physical separations of up to 743000au. We also find four M-L
systems, three of which are new detections. No colder companion was
identified in any of the 219 M and L subdwarfs of the sample, mainly
because of limitations on the detection of faint sources with Gaia. We
infer a frequency of wide systems for sdM5-9.5 of
0.60-0.60+1.17% for projected physical separations larger than
1360au (up to 142400au). This study shows a multiplicity rate of
1.0-1.0+2.0% in sdMs, and 1.9-1.9+3.7% in extreme M subdwarfs.
We did not find any companion for the ultra M subdwarfs of our sample,
establishing an upper limit of 5.3% on binarity for these objects.
Description:
We present a dedicated search for wide companions to a sample of
spectroscopically confirmed M and L subdwarfs. We identified several
candidates around six subdwarfs.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 98 219 Properties of all subdwarfs in the sample
tablea2.dat 76 219 Astrometric data of the subdwarfs
tablea3.dat 91 62 Astrometric data of the companion candidates
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/219] Number of the subdwarf inside the sample
5- 28 A24 --- Name Denomination of the subdwarf in the catalogues
30- 31 I2 h RAh Right ascension of the subdwarf (J2000) (1)
33- 34 I2 min RAm Right ascension of the subdwarf (J2000) (1)
36- 40 F5.2 s RAs Right ascension of the subdwarf (J2000) (1)
42 A1 --- DE- Declination sign of the subdwarf (J2000) (1)
43- 44 I2 deg DEd Declination of the subdwarf (J2000) (1)
46- 47 I2 arcmin DEm Declination of the subdwarf (J2000) (1)
49- 52 F4.1 arcsec DEs Declination of the subdwarf (J2000) (1)
54- 72 I19 --- GaiaDR2 ? Identification number of the subdwarf in
Gaia DR2 catalogue
74- 87 A14 --- SpType Spectral type of the subdwarf
89- 98 A10 --- Ref Literature reference for the above data per
subdwarf (2)
--------------------------------------------------------------------------------
Note (1): The values of the coordinates are obtained from the catalogue
determined by the prefix of the names (SDSS, ULAS, 2MASS, LSR, LHS, SSSPM,
and APMPM).
Note (2): References as follows:
1 = Bowler et al. (2010ApJ...710...45B 2010ApJ...710...45B)
2 = Burgasser et al. (2003ApJ...592.1186B 2003ApJ...592.1186B)
3 = Burgasser et al. (2004ApJ...604..827B 2004ApJ...604..827B)
4 = Cushing et al. (2009ApJ...696..986C 2009ApJ...696..986C)
5 = Gizis (1997AJ....113..806G 1997AJ....113..806G, Cat. J/AJ/113/806)
6 = Gizis & Reid (1997PASP..109..849G 1997PASP..109..849G, Cat. J/PASP/109/849)
7 = Reid et al. (1997PASP..109..559R 1997PASP..109..559R)
8 = Gizis & Reid (2000PASP..112..610G 2000PASP..112..610G)
9 = Kirkpatrick et al. (2010ApJS..190..100K 2010ApJS..190..100K, Cat. J/ApJS/190/100)
10 = Lepine et al. (2003AJ....125.1598L 2003AJ....125.1598L, Cat. J/AJ/125/1598)
11 = Lepine & Scholz (2008ApJ...681L..33L 2008ApJ...681L..33L)
12 = Lodieu et al. (2010ApJ...708L.107L 2010ApJ...708L.107L)
13 = Lodieu et al. (2012A&A...542A.105L 2012A&A...542A.105L)
14 = Lodieu et al. (2017A&A...598A..92L 2017A&A...598A..92L, Cat. J/A+A/598/A92)
15 = Reid et al. (2004AJ....128..463R 2004AJ....128..463R, Cat. J/AJ/128/463)
16 = Reid & Gizis (2005PASP..117..676R 2005PASP..117..676R, Cat. J/PASP/117/676)
17 = Riaz et al. (2008ApJ...672.1153R 2008ApJ...672.1153R)
18 = Schmidt et al. (2010AJ....139.1045S 2010AJ....139.1045S)
19 = Scholz et al. (2004A&A...425..519S 2004A&A...425..519S)
20 = Scholz et al. (2004A&A...428L..25S 2004A&A...428L..25S)
21 = Schweitzer et al. (1999A&A...350L..62S 1999A&A...350L..62S)
22 = Sivarani et al. (2009ApJ...694L.140S 2009ApJ...694L.140S)
23 = Zhang et al. (2013MNRAS.434.1005Z 2013MNRAS.434.1005Z)
24 = Zhang et al. (2017MNRAS.464.3040Z 2017MNRAS.464.3040Z)
25 = Zhang et al. (2018MNRAS.479.1383Z 2018MNRAS.479.1383Z)
26 = Zhang et al. (2018MNRAS.480.5447Z 2018MNRAS.480.5447Z)
27 = Lodieu et al. (2019A&A...628A..61L 2019A&A...628A..61L, Cat. J/A+A/628/A61)
28 = Zhang (2019MNRAS.489.1423Z 2019MNRAS.489.1423Z)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/219] Number of the subdwarf inside
the sample
5- 13 F9.3 mas/yr pmRA Subdwarf proper motion, RA component,
pmRA*cosDE
15- 21 F7.3 mas/yr e_pmRA rms uncertainty on pmRA
23- 31 F9.3 mas/yr pmDE Subdwarf proper motion, DE component
33- 39 F7.3 mas/yr e_pmDE rms uncertainty on pmDE
41- 49 A9 --- r_pm Origin of the value used in the work
(Gaia DR2 or calculated by us)
51- 55 F5.1 pc Dist Distance to the subdwarf
57- 61 F5.1 pc e_Dist rms uncertainty on Distance
63- 71 A9 --- r_Dist Origin of the value of the distance used in
the work (Gaia DR2 or calculated by us)
73- 76 F4.2 deg RadSearch Radius for searching for possible
candidates to companions
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- CandId Number YY of the possible candidate to
companion in relation to the XXX
subdwarf: XXX-YY
8- 26 I19 --- GaiaDR2 Identification number of the companion in
Gaia DR2 catalogue
28- 29 I2 h RAh Right ascension of the companion candidate
(ICRS) at Ep=2015.5
31- 32 I2 min RAm Right ascension of the companion candidate
(ICRS) at Ep=2015.5
34- 38 F5.2 s RAs Right ascension of the companion candidate
(ICRS) at Ep=2015.5
40 A1 --- DE- Declination sign of the companion candidate
(ICRS) at Ep=2015.5
41- 42 I2 deg DEd Declination of the companion candidate
(ICRS) at Ep=2015.5
44- 45 I2 arcmin DEm Declination of the companion candidate
(ICRS) at Ep=2015.5
47- 51 F5.2 arcsec DEs Declination of the companion candidate
(ICRS) at Ep=2015.5
52- 57 F6.1 mas/yr pmRA Candidate proper motion, RA component,
pmRA*cosDE
59- 61 F3.1 mas/yr e_pmRA rms uncertainty on pmRA
63- 68 F6.1 mas/yr pmDE Candidate proper motion, DE component
70- 72 F3.1 mas/yr e_pmDE rms uncertainty on pmDE
74- 78 F5.1 pc Dist Distance of the companion candidate
80- 84 F5.1 pc e_Dist rms uncertainty on Distance
86- 90 F5.2 arcmin Sep Separation between subdwarf and companion
candidate
91 A1 --- n_Sep [a] a: Distance is in arcsec
--------------------------------------------------------------------------------
Acknowledgements:
Javier Gonzalez-Payo, fcojgonz(at)ucm.es
(End) Patricia Vannier [CDS] 20-Apr-2021