J/MNRAS/503/938 New young stars within ∼200 pc (Zerjal+, 2021)
A spectroscopically confirmed Gaia-selected sample of 318 new young stars
within ∼200 pc.
Zerjal M., Rains A.D., Ireland M.J., Zhou G., Kammerer J., Wallace A.,
Orenstein B.J., Nordlander T., Abbot H., Chang S.-W.
<Mon. Not. R. Astron. Soc., 503, 938-952 (2021)>
=2021MNRAS.503..938Z 2021MNRAS.503..938Z (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, pre-main sequence ; Radial velocities ;
Optical
Keywords: stars: activity - stars: late-type - stars: pre-main-sequence
Abstract:
In the Gaia era, the majority of stars in the Solar neighbourhood have
parallaxes and proper motions precisely determined while spectroscopic
age indicators are still missing for a large fraction of low-mass
young stars. In this work, we select 756 overluminous late K and early
M young star candidates in the southern sky and observe them over 64
nights with the ANU 2.3-m Telescope at Siding Spring Observatory using
the Echelle (R=24000) and Wide Field spectrographs (WiFeS,
R=3000-7000). Our selection is kinematically unbiased to minimize the
preference against low-mass members of stellar associations that
dissipate first and to include potential members of diffuse
components. We provide measurements of Hα and calcium H&K
emission, as well as of LiI 6708Å in absorption. This enables
identification of stars as young as 10-30Myr - a typical age range
for stellar associations. We report on 346 stars showing detectable
lithium absorption, 318 of which are not included in existing
catalogues of young stars. We also report 125 additional stars in our
sample presenting signs of stellar activity indicating youth but with
no detectable lithium. Radial velocities are determined for WiFeS
spectra with a precision of 3.2km/s and 1.5km/s for the Echelle
sample.
Description:
We selected and observed 756 overluminous late K and early M dwarfs
with at least 1 magnitude above the main sequence and with Gaia G
magnitude between 12.5 and 14.5. The kinematic cut was wide enough to
avoid a bias towards higher mass stars and include low-mass dwarfs.
Observations were carried out over 64 nights with the Echelle and Wide
Field Spectrographs at the ANU 2.3-m telescope in Siding Spring
observatory. The analysis revealed 549 stars with at least one feature
of stellar youth, i.e. the lithium absorption line or excess emission
in Hα or calcium H&K lines. The strength of the lithium
absorption line indicates that 349 stars are younger than 25Myr.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 117 824 List of young star candidates with their
radial velocities and youth signatures
tableb1.dat 112 31 List of stars from the Pace (2013A&A...551L...8P 2013A&A...551L...8P,
Cat. J/A+A/551/L8) compilation with literature
values and used here to calibrate the S-index
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/551/L8 : Chromospheric activity of field stars (Pace, 2013)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaDR2 ? Gaia DR2 source_id
21- 36 A16 --- 2MASS 2MASS name (HHMMSSss+DDMMSSs)
38- 42 F5.2 mag Gmag ? Gaia G magnitude
44- 47 F4.2 mag BP-W1 ? Gaia BP minus Wise W1 colour index
49- 52 F4.2 mag BP-RP ? Gaia BP minus RP colour index
54- 58 F5.2 --- RUWE ? Gaia RUWE
60- 69 A10 "date" Obs.date Observation date
71- 77 A7 --- Inst Instrument
79- 81 I3 --- S/N(B) ? Signal-to-noise ratio in B band
83- 85 I3 --- S/N(R) ? ignal-to-noise ratio in R band
87- 91 F5.1 km/s RV ? Radial velocity
93- 95 F3.1 km/s e_RV ? Radial velocity error
97-101 F5.2 --- logR'HK ? R'HK chromospheric activity index
103-107 F5.2 0.1nm EW(Ha) ? Hα equivalent width
109-113 F5.2 0.1nm EW(Li) ? Li equivalent width
115 I1 --- Binary [0/1] Binary ? (1=true)
117 I1 --- Balmer [0/1] Balmer ? (1=true)
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number
8- 26 I19 --- GaiaDR2 Gaia DR2 number
28- 37 A10 "date" Obs.date Observation date
39- 43 F5.3 --- Sraw S-index measured with the WiFeS instrument
45- 49 F5.3 --- Smin Lower value of S-index
51- 55 F5.3 --- Smax Highest value of S-index
57- 62 F6.3 [-] logRmin Conversion of Smin into logR'HK
64- 69 F6.3 [-] logRmax Conversion of Smax into logR'HK
71- 74 F4.2 mag BP-RP BP-RP colour index
76-112 A37 --- Refs References (1)
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Note (1): References listed in the original form from Pace (2013,
Cat. J/A+A/551/L8) (doubled letters correspond to studies with repeated
measurements) as follows:
1 = Arriagada et al. (2011ApJ...734...70A 2011ApJ...734...70A)
2 = Baliunas et al. (1995ApJ...438..269B 1995ApJ...438..269B)
3 = Buccino et al. (2008, Cat. J/A+A/483/903)
4 = Cincunegui et al. (2007, Cat. J/A+A/469/309)
5 = Duncan et al. (1991ApJS...76..383D 1991ApJS...76..383D, Cat. III/159)
6 = Gray et al. (2003, Cat. J/AJ/126/2048)
7 = Gray et al. (2006, Cat. J/AJ/132/161)
8 = Hall et al. (2007AJ....133.2206H 2007AJ....133.2206H)
9 = Henry et al. (1996, cat. J/AJ/111/439)
a = Isaacson and Fischer (2010, Cat. J/ApJ/725/875)
b = Jenkins et al. (2011, Cat. J/A+A/531/A8)
e = Lopez-Santiago et al. (2010A&A...514A..97L 2010A&A...514A..97L)
f = Schroder et al. (2009, Cat. J/A+A/493/1099)
g = Strassmeier et al. (2000, Cat. J/A+AS/142/275)
h = Tinney et al. (2002MNRAS.332..759T 2002MNRAS.332..759T)
i = White et al. (2007, Cat. J/AJ/133/2524)
j = Wright et al. (2004, Cat. J/ApJS/152/261)
k = Mamajek & Hillenbrand (2008, Cat. J/ApJ/687/1264)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2023