J/ApJ/846/93 The multiplicity of M dwarfs in young moving groups (Shan+, 2017)
The multiplicity of M dwarfs in young moving groups. Shan Y., Yee J.C., Bowler B.P., Cieza L.A., Montet B.T., Canovas H., Liu M.C., Close L.M., Hinz P.M., Males J.R., Morzinski K.M., Vaz A., Bailey V.P., Follette K.B. (The MagAO Team) <Astrophys. J., 846, 93 (2017)> =2017ApJ...846...93S
ADC_Keywords: Stars, double and multiple; Photometry, infrared; Spectral types; Proper motions; Stars, masses; Stars, distances Keywords: binaries: visual ; methods: observational ; methods: statistical ; stars: low-mass ; stars: pre-main sequence ; techniques: photometric Abstract: We image 104 newly identified low-mass (mostly M-dwarf) pre-main sequence (PMS) members of nearby young moving groups (YMGs) with Magellan Adaptive Optics (MagAO) and identify 27 stellar binaries with instantaneous projected separation as small as 40mas. Fifteen were previously unknown. The total number of multiple systems in this sample including spectroscopic and visual binaries from the literature is 36, giving a raw stellar multiplicity rate of at least 35-4+5% for this population. In the separation range of roughly 1-300au in which infrared AO imaging is most sensitive, the raw multiplicity rate is at least 24-4+5% for binaries resolved by the MagAO infrared camera (Clio). The M-star subsample of 87 stars yields a raw multiplicity of at least 30-4+5% over all separations, 21-4+5% for secondary companions resolved by Clio from 1 to 300au (23-4+5% for all known binaries in this separation range). A combined analysis with binaries discovered by the Search for Associations Containing Young stars shows that stellar multiplicity fraction as a function of mass over the range of 0.2 to 1.2M☉ appears to be linearly flat, in contrast to the field, where multiplicity increases with mass. After bias corrections are applied, the multiplicity of low-mass YMG members (0.2-0.6M☉) is in excess of the field. The overall multiplicity fraction is also consistent with being constant in age and across YMGs, which suggests that multiplicity rates for this mass range are largely set by 10Myr without appreciable evolution thereafter. Description: Adaptive optics observations were conducted on the 6.5m Magellan Clay Telescope at the Las Campanas Observatory in Chile using the MagAO instrument. Images were taken with two science cameras simultaneously: Clio in the near-infrared, and VisAO in the optical. The MagAO/Clio observations in H or Ks bands span 2014 Apr 17-21 to 2015 Nov 26-27. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 103 105 Young moving group (YMG) low-mass target sample table4.dat 58 105 Target HWHMs table5.dat 83 41 Astrometric measurements for visual binary (VB) candidates from this work table8.dat 126 27 System properties of visual doubles observed by Clio
See also: I/322 : UCAC4 Catalogue (Zacharias+, 2012) VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006) J/A+A/356/541 : T Tauri stars in the Sco-Cen OB association (Koehler+, 2000) J/AJ/123/1570 : alpha Persei and Praesepe Clusters (Patience+, 2002) J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004) J/ApJS/173/104 : Stellar population in Chamaeleon I (Luhman, 2007) J/ApJ/696/L84 : Primordial circumstellar disks in binaries (Cieza+, 2009) 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/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012) J/ApJ/745/19 : Binary systems in Taurus-Auriga (Kraus+, 2012) J/ApJ/762/88 : Young stellar kinematic group cand. members (Malo+, 2013) J/MNRAS/435/1325 : Membership of the ε Cha association (Murphy+, 2013) J/A+A/568/A26 : SACY. V. Multiple systems (Elliott+, 2014) J/ApJ/783/121 : BANYAN II. Nearby young assoc. cand. members (Gagne+, 2014) J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014) J/ApJ/785/47 : Sources around target stars in Upper Sco (Lafreniere+, 2014) J/ApJ/788/81 : BANYAN III. RVel & rotation of low-mass stars (Malo+, 2014) J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015) J/A+A/580/A88 : Stellar multiplicity in 3-1000AU (Elliott+, 2015) J/MNRAS/449/2618 : M-dwarfs in Multiples (MinMs) survey. I. (Ward-Duong+, 2015) J/A+A/590/A13 : New candidate members in young associations (Elliott+, 2016) J/AJ/152/8 : Stellar multiplicity on planetary systems I. (Kraus+, 2016) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 6 A6 --- YMG Abbreviated YMG name (1) 8- 24 A17 --- 2MASS 2MASS target identifier 26 A1 --- f_2MASS [a] Flag on 2MASS (2) 28- 38 A11 --- AName Abbreviated name of target 40- 41 I2 h RAh [0/23] Hour of Right Ascension (J2000) 43- 44 I2 min RAm Minute of Right Ascension (J2000) 46- 50 F5.2 s RAs Second of Right Ascension (J2000) 52 A1 --- DE- [-] Sign of the Declination (J2000) 53- 54 I2 deg DEd [32/79] Degree of Declination (J2000) 56- 57 I2 arcmin DEm Arcminute of Declination (J2000) 59- 62 F4.1 arcsec DEs Arcsecond of Declination (J2000) 64- 69 A6 --- SpT MK spectral type 71- 73 I3 pc Dist [16/120] Distance estimate (3) 75- 76 I2 pc e_Dist [0/19] Uncertainty in Dist 78 A1 --- f_Dist [cdef] Flag on Dist (4) 80 I1 --- r_Dist [1/5] Reference on Dist (5) 82- 86 F5.2 mag Jmag [7.5/11.7] 2MASS apparent J band magnitude 88- 92 F5.2 mag Hmag [6.9/11.2] 2MASS apparent H band magnitude 94- 98 F5.2 mag Ksmag [6.7/11] 2MASS apparent Ks band magnitude 100-103 F4.2 Msun Mp [0.1/0.9]? Primary Mass (6)
Note (1): Full name as follows: TucHor = Tucana-Horologium (51 sources); Col = Columba (15 sources); bPic = Β Pictoris (13 sources); Arg = Argus (10 sources); Car = Carina (6 sources); ABDor = AB Doradus (6 sources); TWA = TW Hydrae (4 sources). Note (2): a = A YMG designation is ambiguous according to Malo+ 2013, J/ApJ/762/88 and 2014, J/ApJ/788/81 Note (3): The distance estimate for each target is either statistical/kinematical or from trigonometric references unless a flag is present in "f_Dist". Note (4): Flag as follows: c = Gaia Collaboration (2016A&A...595A...2G); d = Donaldson et al. (2016ApJ...833...95D); e = Weinberger et al. (2013ApJ...762..118W); f = no distance error is reported in source reference. Error estimate is based on the average error for other targets in this YMG. Note (5): Reference as follows: 1 = Malo et al. 2013, J/ApJ/762/88 2 = Malo et al. 2014, J/ApJ/788/81 3 = Kraus et al. 2014, J/AJ/147/146 4 = Moor et al. 2013MNRAS.435.1376M 5 = Rodriguez et al. 2013ApJ...774..101R Note (6): Mass calculations are discussed in Sections 4.1 and 5.2.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 11 A11 --- AName Abbreviated name of target 13 I1 --- Nep [1/4] Number of epochs observed 15- 24 A10 "Y-M-D" Epoch Best epoch (UT date) 26- 27 A2 --- Band Band (H or Ks) 29- 33 F5.3 arcsec bmin [0.02/0.3] Semi-Minor axis of PSF at half-max 35- 39 F5.3 arcsec e_bmin [0/0.05] Uncertainty in bmin 41- 44 F4.2 --- b/a [0.6/1] Axis ratio of PSF at half-max; Minor/Major 46- 49 F4.2 --- e_b/a [0/0.2] Uncertainty in b/a 51- 53 I3 deg PA [4/178] Orientation angle of PSF; East of North 55- 56 I2 deg e_PA [1/47] Uncertainty in PA 58 A1 --- Mult Multiplicity status (1)
Note (1): Status as follows: N = single; Y = multiple within 4.0 arcsec based on our observations and known VBs and SBs from the literature.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 11 A11 --- AName Abbreviated target name 13- 17 F5.1 [mas/yr] pmRA [-54.6/97.2]? Proper motion in RA; *cos(DEC) (1) 19- 21 F3.1 [mas/yr] e_pmRA [0.9/6.3]? Error in pmRA 23- 28 F6.1 [mas/yr] pmDE [-104.1/45.8]? Proper motion in Declination 30- 32 F3.1 [mas/yr] e_pmDE [0.8/5.1]? Error in pmDE 34- 43 A10 "Y-M-D" Epoch Epoch of observation (UT date) 45- 46 A2 --- Band Band (H or Ks (1 occurrence)) 48- 52 F5.3 arcsec Sep [0.05/3.2]? Angular separation 54- 58 F5.3 arcsec e_Sep [0/0.05]? Error in Sep 59 A1 --- f_Sep [ce] Flag on Sep (2) 61- 65 F5.1 deg PA [8/333]? Position angle; east of north 67- 70 F4.2 deg e_PA [0.3/4.5]? Error in PA 72- 75 F4.2 mag dMag [0.03/5.2]? Delta-magnitude 77- 80 F4.2 mag e_dMag [0.01/0.3]? Error in dMag 82- 83 A2 --- CoMv Comoving flag (G1)
Note (1): Proper motions from the UCAC4 catalog (Zacharias+ 2012, I/322) except that of J1516-5855, which is from NOMAD catalog (Zacharias+ 2005, I/297), which was used in the analysis by Malo+ 2013, J/ApJ/762/88 Note (2): Flag as follows: c = No data is reported for epochs in which our fit could not reliably recover both components. e = Poor observing conditions resulted in a highly uncertain fit for this epoch. Possible degeneracy between the binary parameters and AO correction may explain why the measurements are inconsistent with the other epochs.
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 6 A6 --- YMG Abbreviated YMG name 8- 18 A11 --- AName Abbreviated target name 20- 23 A4 --- SpT MK spectral type 25- 27 I3 pc Dist [16/120] Distance 29- 30 I2 pc e_Dist [1/19] Error in distance 32- 39 A8 --- Epoch Best epoch of observation 41- 42 A2 --- Band Band (H or Ks (1 occurrence)) 44- 48 F5.3 arcsec Sep [0.05/3.2] Angular separation 50- 54 F5.3 arcsec e_Sep [0/0.03] Error on Sep 56- 60 F5.1 deg PA [8/326] Position angle 62- 65 F4.2 deg e_PA [0.3/4.5] Error on PA 67- 70 F4.2 mag dMag [0.03/5.1] Delta-magnitude 72- 75 F4.2 mag e_dMag [0.01/0.3] Error on dMag 77- 78 A2 --- CoMv Comoving flag (G1) 80- 85 F6.4 % Punbd [0/0.08] Unbound probability 87- 91 F5.1 AU PSep [1.1/281.4] Projected physical separation 93- 96 F4.1 AU e_PSep [0.1/16.1] Error on PSep 98-101 F4.2 [Msun] Mp [0.1/0.9]? Primary mass 103-106 F4.2 [Msun] Ms [0.04/0.7]? Secondary mass 108-110 F3.1 --- q [0.1/1]? Mass ratio; Mprim/Msec 112-114 A3 --- Known Known binary? (14 "yes") 116-126 A11 --- Notes Notes (1)
Note (1): Note as follows: 1 = 4.4" ∼200 AU triple companion also detected in Clio. 2 = VB also imaged by Janson+ 2017, J/A+A/599/A70 3 = Flagged as probable binary by BANYAN (Malo+ 2013, J/ApJ/762/88) based on YMG membership analysis (see text). 4 = Not flagged as probable binary by BANYAN (Malo+ 2013, J/ApJ/762/88) based on YMG membership analysis. 5 = VBs also detected by Elliott+ 2015, J/A+A/580/A88 6 = 0.63 VB detected by Chauvin+ 2010, J/A+A/509/A52 7 = SB1 according to Malo+ 2014, J/ApJ/788/81 8 = Previously suggested by Malo+ 2013, J/ApJ/762/88 to belong to the field when RV data is incorporated into the YMG membership analysis. 9 = 0.8 VB according to Torres+ 2008 (Handbook of Star Formation Regions, Vol. II ed B. Reipurth (San Francisco, CA: ASP). 10 = 7.9 VB detected by Malo+ 2014, J/ApJ/788/81 11 = 0.7 VB suspected by Zuckerman+ 2001ApJ...549L.233Z 12 = 0.62 VB resolved by Janson+ 2012, J/ApJ/754/44
Global notes: Note (G1): Flag as follows: C = co-moving; CO = co-moving with orbital motion; B = background; I = indeterminate.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Apr-2018
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