J/A+A/590/A13 New candidate members in young associations (Elliott+, 2016)
Search for associations containing young stars (SACY).
VII. New stellar and sub-stellar candidate members in the young associations.
Elliott P., Bayo A., Melo C.H.F., Torres C.A.O., Sterzik M.F., Quast G.R.,
Montes D., Brahm R.
<Astron. Astrophys. 590, A13 (2016)>
=2016A&A...590A..13E 2016A&A...590A..13E (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Clusters, globular ; Proper motions ;
Photometry ; Equivalent widths
Keywords: data analysis -
open clusters and associations: general proper motions -
stars: kinematics and dynamics - stars: low-mass
Abstract:
The young associations offer us one of the best opportunities to study
the properties of young stellar and sub-stellar objects and directly
image planets thanks to their proximity (<200pc) and age (5-150Myr).
However, many previous works have been limited to identifying the
brighter, more active members (1Msun) due to photometric survey
sensitivities limiting the detections of lower-mass objects.
We search the field of view of 542 previously identified members of
the young associations to identify wide / extremely wide
(1000-100,000au in physical separation) companions. Methods. We have
combined 2MASS near-infrared photometry (J, H, K) with proper motion
values (from UCAC4, PPMXL, NOMAD) to identify companions in the field
of view of known members. We collated further photometry and
spectroscopy from the literature and conducted our own high-resolution
spectroscopic observations for a sub-sample of candidate members. This
complementary information allowed us to assess the efficiency of our
method.
We identified 84 targets (45:0.2-1.3M☉, 17:0.08-0.2M☉,
22:<0.08M☉) in our analysis, 10 of which have been identified
from spectroscopic analysis in previous young association works. For
33 of these 84 we were able to further assess their membership using a
variety of properties (X-ray emission, UV excess, Hα, lithium
and KI equivalent widths, radial velocities, and CaH indices). We
derive a success rate of 76-88% for this technique based on the
consistency of these properties.
Once confirmed, the targets identified in this work would
significantly improve our knowledge of the lower-mass end of the young
associations. Additionally, these targets would make an ideal new
sample for the identification and study of planets around nearby young
stars. Given the predicted sub-stellar mass of the majority of these
new candidate members and their proximity, high-contrast imaging
techniques would facilitate the search for new low-mass planets.
Description:
Full photometric, spectroscopic and kinematic properties, with
references, of new candidate members in the moving groups, identified
in this work.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
appene.dat 419 83 Properties of new candidate members (full table4)
tabled1.dat 110 542 Basic properties of the original sample used
in this work
refs.dat 86 31 References
--------------------------------------------------------------------------------
See also:
J/A+A/460/695 : Search for Associations Containing Young stars
(Torres+, 2006)
J/A+A/508/833 : SACY III. Li abundances (da Silva+, 2009)
J/MNRAS/431/1005 : SACY IV. IC 2391 and Argus young stars (de Silva+, 2013)
J/A+A/568/A26 : SACY V. Multiple systems (Elliott+, 2014)
J/A+A/580/A88 : SACY VI. Stellar multiplicity in 3-1000AU (Elliott+, 2015)
Byte-by-byte Description of file: appene.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [2MASS]
7- 23 A17 --- 2MASS 2MASS designation (JHHMMSSss+DDMMSSs)
25- 33 F9.5 deg RAdeg Right ascension (J2000.0)
35- 44 F10.6 deg DEdeg Declination (J2000.0)
46- 54 F9.5 pc Distk Distance (kinematic)
56- 63 F8.4 pc Distp ? Distance (parallactic)
66- 70 F5.1 mas/yr pmRA Proper motion in right ascension
72- 74 F3.1 mas/yr e_pmRA Uncertainty of pmRA
76- 80 F5.1 mas/yr pmDE Proper motion in declination
82- 85 F4.1 mas/yr e_pmDE Uncertainty of pmDE
87- 91 A5 --- r_pmDE Reference for proper motion,
in refs.dat file
93- 96 F4.1 km/s RV ? Radial velocity
98-100 F3.1 km/s e_RV ? Uncertainty of RV
102-108 A7 --- r_RV Reference for radial velocity,
in refs.dat file
110-115 F6.3 mag Hmag H magnitude
117-122 F6.3 mag Jmag J magnitude
124-129 F6.3 mag Kmag K magnitude
131-133 A3 --- Assoc Association name
135-137 I3 0.1pm EWLi ? Lithium equivalent width
139-145 A7 --- r_EWLi Reference for lithium equivalent width,
in refs.dat file
147-154 F8.5 mag Bmag ? B magnitude
156-183 A28 --- r_Bmag References for B magnitude, in refs.dat file
185-192 F8.5 mag Vmag ? V magnitude
194-220 A27 --- r_Vmag References for V magnitude, in refs.dat file
222-229 F8.5 mag Rmag ? R magnitude
230-254 A25 --- r_Rmag References for R magnitude,
in refs.dat file
255-260 F6.3 0.1nm EWHa ? H alpha equivalent width
262-266 F5.3 0.1nm e_EWHa ? Uncertainty of EWHa
268-274 A7 --- r_EWHa Reference for H alpha equivalent width,
in refs.dat file
276-282 F7.5 [-] logLX/Lbol ? X-ray/bolometric luminosity ratio (log)
284-290 A7 --- r_logLX/Lbol Reference for logLX/Lbol, in refs.dat file
292-296 F5.3 --- CaH2 ? Calcium Hydroxide index 2
298-304 A7 --- r_CaH2 Reference for CaH2, in refs.dat file
306-310 F5.3 --- CaH3 ? Calcium Hydroxide index 3
312-318 A7 --- r_CaH3 Reference for CaH3, in refs.dat file
320-325 F6.4 0.1nm EWNaI ? Sodium I equivalent width
327-333 A7 --- r_EWNaI Reference for EWNaI, in refs.dat file
335-340 F6.4 0.1nm EWKI ? Potassium I equivalent width
342-348 A7 --- r_EWKI Reference for EWKI, in refs.dat file
350-375 A26 --- c Youth consistent quantities
377-378 A2 --- Memb [YN? ] Membership flag
380-417 A38 --- r_c References for youth consistent quantities,
in refs.dat file
419 A1 --- Cata [Y] Optical flaring in Catalina photometry
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tabled1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Assoc Association name
5- 29 A25 --- Name Star name
31- 32 I2 h RAh Right ascension (J2000)
34- 35 I2 min RAm Right ascension (J2000)
37- 40 F4.1 s RAs Right ascension (J2000)
42 A1 --- DE- Declination sign (J2000)
43- 44 I2 deg DEd Declination (J2000)
46- 47 I2 arcmin DEm Declination (J2000)
49- 52 F4.1 arcsec DEs Declination (J2000)
54- 58 F5.1 pc Dist Distance
59 A1 --- n_Dist [a] Note on Dist (1)
61- 64 F4.1 mag Jmag J magnitude
66- 69 F4.1 mag Hmag H magnitude
71- 74 F4.1 mag Kmag K magnitude
78- 83 F6.1 mas/yr pmRA Proper motion along RA, pmRA*cosDE
85- 88 F4.1 mas/yr e_pmRA rms uncertainty on pmRA
93- 98 F6.1 mas/yr pmDE Proper motion along DE
100-103 F4.1 mas/yr e_pmDE rms uncertainty on pmDE
105-110 A6 --- Ref Membership reference (2)
--------------------------------------------------------------------------------
Note (1): a: Distances from parallax measurements.
Note (2): References as follows:
1 = SACY works (Torres et al., 2008, Cat. J/A+A/460/695;
Elliott et al., 2014, Cat. J/A+A/568/A26)
2 = Zuckerman et al. (2011ApJ...732...61Z 2011ApJ...732...61Z)
3 = Malo et al. (2014, Cat. J/ApJ/788/81)
4 = Murphy & Lawson (2015, Cat. J/MNRAS/447/1267)
5 = Kraus et al. (2014, Cat. J/AJ/147/146)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Ref Reference code
9- 27 A19 --- BibCode BibCode
29- 49 A21 --- Aut Author's name
51- 86 A36 --- Com Comments
--------------------------------------------------------------------------------
Acknowledgements:
Paul Elliott, pelliott(at)eso.org
References:
Torres et al., Paper I 2006A&A...460..695T 2006A&A...460..695T, Cat. J/A+A/460/695
Viana Almeida et al., Paper II 2009A&A...501..965V 2009A&A...501..965V
da Silva et al., Paper III 2009A&A...508..833D 2009A&A...508..833D, Cat. J/A+A/508/833
de Silva et al., Paper IV 2013MNRAS.431.1005D 2013MNRAS.431.1005D, Cat. J/MNRAS/431/1005
Elliott et al., Paper V 2014A&A...568A..26E 2014A&A...568A..26E, Cat. J/A+A/568/A26
Elliott et al., Paper VI 2014A&A...580A..88E 2014A&A...580A..88E, Cat. J/A+A/580/A88
History:
28-Apr-2016: on-line version
15-Sep-2016: table D1 added (from electronic version of the paper)
09-Mar-2018: Sign of declination corrected in appene.dat file
(End) Paul Elliott [ESO, Chile], Patricia Vannier [CDS] 17-Mar-2016