J/AJ/161/87 Gaia data for members of εCha (Dickson-Vandervelde+, 2021)
Gaia-based isochronal, kinematic, and spatial analysis of the ε Cha
association.
Dickson-Vandervelde D.A., Wilson E.C., Kastner J.H.
<Astron. J., 161, 87 (2021)>
=2021AJ....161...87D 2021AJ....161...87D
ADC_Keywords: Associations, stellar; Stars, pre-main sequence;
Radial velocities; Proper motions; Parallaxes, trigonometric;
Photometry, infrared; Optical
Keywords: Stellar associations ; Pre-main sequence stars
Abstract:
The precise parallax, proper motion, and photometric measurements
contained in Gaia Data Release 2 (DR2) offer the opportunity to
reexamine the membership and ages of nearby young moving groups
(NYMGs), i.e., loose groups of stars of age ≲100Myr in the solar
vicinity. Here, we analyze the available DR2 data for members and
candidate members of the εCha Association (εCA) which,
at an estimated age of ∼3-5Myr, has previously been identified as
among the youngest NYMGs. The several dozen confirmed members of
εCA include MPMus and TCha, two of the nearest stars of
roughly solar mass that are known to host primordial protoplanetary
disks, and the Herbig Ae/Be star HD104237A. We have used Gaia DR2 data
to ascertain the Galactic positions and kinematics and color-magnitude
diagram positions of εCA members and candidates so as to
reassess their membership status and thereby refine estimates of the
distance, age, multiplicity, and disk fraction of the group. Our
analysis yields 36 bona fide εCA members, as well as 20
provisional members, including 3 new members identified here as
comoving companions to previously known εCA stars. We
determine a mean distance to εCA of 101.0±4.6pc and
confirm that, at an age of 5-2+3Myr, εCA represents the
youngest stellar group within ∼100pc of Earth. We identify several new
photometric binary candidates, bringing the overall multiplicity
fraction (MF) of εCA to 40%, intermediate between the MFs of
young T associations and the field.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 145 65 Gaia data for candidate εChA members
table3.dat 102 36 Final εCha association membership list
table4.dat 97 20 Provisional εCha association membership
list
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See also:
III/272 : RAVE 4th data release (Kordopatis+, 2013)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)
J/A+A/551/A46 : Compiled photometry for ChamI & II members (Lopez Marti+,2013)
J/MNRAS/435/1325 : Membership of the ε Cha association (Murphy+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/ApJ/788/81 : BANYAN III. RVel and rotation of low-mass stars (Malo+, 2014)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/A+A/573/A126 : VLT/NaCo Large program I. Sample (Desidera+, 2015)
J/AJ/154/195 : New binaries in the ε Cha association (Briceno+, 2017)
J/ApJ/862/138 : BANYAN. XIII. Nearby young assoc. with Gaia DR2 (Gagne+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/157/234 : ACRONYM. III. Candidate young low-mass stars (Schneider+,2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name Star identifier
25 A1 --- f_Name Flag on Name (1)
27- 34 F8.4 deg RAdeg [142/201] Degree of Right Ascension (J2015.5)
36- 43 F8.4 deg DEdeg [-85/-68] Degree of declination (J2015.5)
45- 50 F6.3 mas plx [1.56/11.99]? Parallaxe
52- 56 F5.3 mas e_plx [0.02/1]? Error on plx
58- 66 F9.6 mag Gmag [4.78/17.2] G-band magnitude
68- 74 F7.5 mag e_Gmag [0.0002/0.2] Error on Gmag
76- 83 F8.5 mag RPmag [-0.16/1.61] RP-band magnitude
85- 91 F7.5 mag e_RPmag [0.0006/0.4] Error on RPmag
93- 99 F7.3 mas/yr pmRA [-60.6/-17.2]? Proper motion in right ascension
101-105 F5.3 mas/yr e_pmRA [0.04/1.7]? Error in pmRA
107-113 F7.3 mas/yr pmDE [-20.3/20.4]? Proper motion in declination
115-119 F5.3 mas/yr e_pmDE [0.03/1.4]? Error in pmDE
121-125 F5.2 km/s RVel [2.7/20.9]? Radial Velocity
127-130 F4.2 km/s e_RVel [0.2/7]? Error on RVel
132-136 F5.2 --- RUWE [0.87/38.3]? Re-normalised unit weight error
138 A1 --- f_RUWE [+] Flag on RUWE (2)
140-145 A6 --- r_RVel References used for RVel (3)
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Note (1): Flags as follows:
a = Murphy+, 2013, J/MNRAS/435/1325 bona fide members (37 occurrences)
b = Murphy+, 2013, J/MNRAS/435/1325 provisional members (7 occurrences)
c = Murphy+, 2013, J/MNRAS/435/1325 rejected members (11 occurrences)
d = Gagne+, 2018, J/ApJ/862/138 members (15 occurrences)
Note (2): Flags as follows:
+ = high astrometric excess noise (6 occurrences)
Note (3): References as follows:
1 = Desidera+, 2015, J/A+A/573/A126
2 = Gaia Collaboration, 2018, I/345
3 = Gontcharov+, 2006AstL...32..759G 2006AstL...32..759G
4 = Grady+, 2004ApJ...608..809G 2004ApJ...608..809G
5 = Guenther+, 2007A+A...467.1147G 2007A+A...467.1147G
6 = Lopez Marti+, 2013, J/A+A/551/A46
7 = Malo+, 2014, J/ApJ/788/81
8 = Murphy+, 2013, J/MNRAS/435/1325
9 = Kordopatis+, 2013, III/272
10 = Schisano+, 2009A+A...501.1013S 2009A+A...501.1013S
11 = Terranegra+,1999A+A...341L..79T 1999A+A...341L..79T
12 = Torres+, 2006, J/A+A/460/695
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name Star identifier
26 A1 --- f_Name [*] Flag on Name (1)
28- 32 A5 --- SpT Spectral Type
34- 40 F7.3 pc Dist [93.04/115.7]? Distance (2)
42- 45 F4.2 pc e_Dist [0.2/3.4]? Negative error on Dist
47- 50 F4.2 pc E_Dist [0.2/3.7]? Positive error on Dist
52- 58 F7.4 mag BPmag [4.86/18.84]? Gaia BP magnitude
60- 65 F6.3 mag Gmag [4.78/17.12]? G-band magnitude
67- 72 F6.3 mag RPmag [4.93/15.95]? Gaia RP magnitude
74- 75 A2 --- f_Jmag Limit flag on Jmag
77- 82 F6.3 mag Jmag [5.02/14.36]? 2MASS J-band magnitude
84- 85 A2 --- f_Hmag Limit flag on Hmag
87- 91 F5.2 mag Hmag [5.04/13.38]? 2MASS H-band magnitude
93- 97 F5.2 mag Kmag [4.59/12.81]? 2MASS K-band magnitude
99-100 A2 --- Mult Multiplicity code (3)
102 A1 --- Disk? IR excess and/or other evidence indicative of
presence of circumstellar disk
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Note (1): Objects marked with * are previously not considered a bona fide member
(Murphy+, 2013, J/MNRAS/435/1325); 3 occurrences
Note (2): Distances have been calculated using the inverse parallax method with
zero-point corrections (Lindegren+, 2018A&A...616A...2L 2018A&A...616A...2L).
Note (3): Codes as follows:
S = suspected spectroscopic binary; Murphy+, 2013, J/MNRAS/435/1325
(1 occurrence)
V = resolved binary; Briceno, 2017, J/AJ/154/195 (6 occurrences)
P = possible photometric binary from this work (5 occurrences)
C = potential wide-separation companion from this work (3 occurrences)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name Star identifier
25- 28 A4 --- SpT Spectral types determined
30- 35 F6.2 pc Dist [85.17/105.3] Distance (1)
37- 40 F4.2 pc e_Dist [0.24/6.11] Negative error on Dist
42- 45 F4.2 pc E_Dist [0.25/7.14] Positive error on Dist
47- 52 F6.3 mag BPmag [6.93/20.48] Gaia BP magnitude
54- 59 F6.3 mag Gmag [6.79/19.93] G-band magnitude
61- 66 F6.3 mag RPmag [6.6/18.19] Gaia RP magnitude
68- 69 A2 --- f_Jmag Limit flag on Jmag
71- 75 F5.2 mag Jmag [6.35/15.85] 2MASS J-band magnitude
77- 78 A2 --- f_Hmag Limit flag on Hmag
80- 84 F5.2 mag Hmag [6.23/15.03] 2 MASS H-band magnitude
86- 87 A2 --- f_Kmag Limit flag on Kmag
89- 93 F5.2 mag Kmag [6.17/12.64] 2MASS K-band magnitude
95 A1 --- Mult Multiplicity code (2)
97 A1 --- Disk? IR excess and/or other evidence indicative of
presence of circumstellar disk
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Note (1): Distances have been calculated using the inverse parallax method with
zero-point corrections (Lindegren+, 2018A&A...616A...2L 2018A&A...616A...2L).
Note (2): Codes as follows:
V = resolved binary; Briceno, 2017, J/AJ/154/195 (2 occurrences)
P = possible photometric binary from this work (1 occurrence)
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History:
From electronic version of the journal
(End) Prepared by Coralie Fix [CDS], 06-May-2021