J/A+A/612/A96 Spectroscopic survey of youngest field stars II. (Frasca+, 2018)
A spectroscopic survey of the youngest field stars in the solar neighborhood.
II. The optically faint sample.
Frasca A., Guillout P., Klutsch A., Freire Ferrero R., Marilli E.,
Biazzo K., Gandolfi D., Montes D.
<Astron. Astrophys. 612, A96 (2018)>
=2018A&A...612A..96F 2018A&A...612A..96F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, pre-main sequence ; X-ray sources ;
Spectroscopy ; Effective temperatures ; Radial velocities ;
Rotational velocities
Keywords: stars: fundamental parameters - stars: chromospheres -
stars: pre-main sequence - binaries: spectroscopic -
techniques: spectroscopic - X-rays: stars
Abstract:
Star formation in the solar neighborhood is mainly traced by young
stars in open clusters, associations, and in the field, which can be
identified, for example, by their X-ray emission. The determination of
stellar parameters for the optical counterparts of X-ray sources is
crucial for a full characterization of these stars.
This work extends the spectroscopic study of the RasTyc sample,
obtained by the cross-correlation of the TYCHO and ROSAT All-Sky
Survey catalogs, to stars fainter than V=9.5mag and aims to identify
sparse populations of young stars in the solar neighborhood.
We acquired 625 high-resolution spectra for 443 presumably young stars
with four different instruments in the northern hemisphere. The radial
and rotational velocity (vsini) of our targets were measured by means
of the cross-correlation technique, which is also helpful to discover
single-lined (SB1), double-lined spectroscopic binaries (SB2), and
multiple systems. We used the code ROTFIT to perform an MK spectral
classification and to determine the atmospheric parameters (Teff,
logg, [Fe/H]) and and vsini of the single stars and SB1 systems. For
these objects, we used the spectral subtraction of slowly rotating
templates to measure the equivalent widths of the Hα and
LiI-6708A lines, which enabled us to derive their chromospheric
activity level and lithium abundance. We made use of Gaia DR1
parallaxes and proper motions to locate the targets in the HR diagram
and to compute the space velocity components of the youngest objects.
We find a remarkable percentage (at least 35%) of binaries and
multiple systems. On the basis of the lithium abundance, the sample of
single stars and SB1 systems appears to be mostly (about 60%) composed
of stars younger than the members of the UMa cluster. The remaining
sources are in the age range between the UMa and Hyades clusters
(about 20%) or older (20%). In total, we identify 42 very young
(PMS-like) stars, which lie above or very close to the Pleiades upper
envelope of the lithium abundance. A significant percentage (about
12%) of evolved stars (giants and subgiants) is also present in our
sample. Some of these stars are also lithium rich (A(Li)>1.4).
Description:
Radial velocity (RV) and projected rotational velocity (vsini) of the
single stars and SB1 systems are quoted in Table A1 along with the V
magnitude and B-V color index. The vsini values measured from the full
width at half maximum of the of the cross-correlation function (CCF)
and by means of the code ROTFIT are both listed in Table A1. Table A2
and A3 report RV and vsini from the CCF for the components of SB2 and
triple (SB3) systems, respectively. Table A4 reports, for the single
stars and SB1 systems, the spectral type, atmospheric parameters
(Teff, logg, and [Fe/H]), the equivalent width of the lithium 6708-A
line (corrected for the FeI blends) and the net equivalent width of
Hα line, measured after the subtraction of the inactive
photospheric template.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 147 449 RV and vsini for the single stars and SB1 systems
tablea2.dat 166 163 RV and vsini for the components of SB2 systems
tablea3.dat 179 20 RV and vsini for the components of SB3 systems
tablea4.dat 144 328 Atmospheric parameters, Hα and LiI EWs
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See also:
J/A+A/454/301 : Radial velocities of 6 binaries (Frasca+, 2006)
J/A+A/490/737 : Radial velocities of 3 RasTyc new triple system (Klutsch+ 2008)
J/A+A/504/829 : Spectroscopic survey of youngest field stars (Guillout+, 2009)
J/ApJ/818/113 : HST observations of QSOs with medium spectra (Neeleman+, 2016)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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3- 12 A10 --- RasTyc RasTyc Name (HHMM+DDMM)
16- 40 A25 --- Name Star Name
42- 43 I2 h RAh Right ascension (J2000)
45- 46 I2 min RAm Right ascension (J2000)
48- 52 F5.2 s RAs Right ascension (J2000)
56 A1 --- DE- Declination sign (J2000)
57- 58 I2 deg DEd Declination (J2000)
60- 61 I2 arcmin DEm Declination (J2000)
63- 66 F4.1 arcsec DEs Declination (J2000)
69- 73 F5.2 mag Vmag ? Johnson V magnitude from TYCHO catalog
78- 82 F5.3 mag B-V ? Johnson B-V colour from TYCHO catalog
85- 94 F10.4 d HJD Reduced Heliocentric Julian day (HJD-2400000)
97-103 F7.2 km/s HRV Heliocentric Radial Velocity
107-111 F5.2 km/s e_HRV Heliocentric Radial Velocity error
113 A1 --- l_vsini Limit flag on vsini
114-118 F5.1 km/s vsiniC ? Projected rotational velocity - CCF
120-124 F5.1 km/s e_vsiniC ? Projected rotational velocity error
127-131 F5.1 km/s vsini ? Projected rotational velocity - ROTFIT
134-137 F4.1 km/s e_vsini ? Projected rotational velocity error
141-142 A2 --- Inst Spectrograph (1)
145-147 A3 --- Notes Individual notes (2)
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Note (1): Spectrograph as follows:
SA = SARG
AU = AURELIE
EL = ELODIE
FR = FRESCO
Note (2): Notes as follows:
SP = Small-amplitude secondary peak in the CCF. Likely SB2. See Table A2.
e = Coordinates from 2MASS (Cat. II/246) catalog.
f = Close visual pair, sep=0.85". B-V is probably unreliable.
g = Close visual binary. Composite spectrum with broad + narrow lines.
h = Close visual pair. RV and vsini are for the B component.
* = Double-peaked CCF. Possible SB2 with blended lines. See Table A2.
** = Newly discovered close visual binary. Sep=1.9", ΔV=1.15mag.
*** = Tertiary component of a W_UMa-type inner binary
(Rucinski et al., 2008, Cat. J/AJ/136/586).
AC = Asymmetric CCF. Possible SB2 with blended lines. See Table A2.
HT = Hierarchical triple system. RV and vsini of the components in Table A3.
VP = Close visual pair.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 12 A10 --- RasTyc RasTyc Name (HHMM+DDMM)
16- 40 A25 --- Name Star Name
42- 43 I2 h RAh Right ascension (J2000)
45- 46 I2 min RAm Right ascension (J2000)
48- 52 F5.2 s RAs Right ascension (J2000)
56 A1 --- DE- Declination sign (J2000)
57- 58 I2 deg DEd Declination (J2000)
60- 61 I2 arcmin DEm Declination (J2000)
63- 66 F4.1 arcsec DEs Declination (J2000)
69- 73 F5.2 mag Vmag Johnson V magnitude from TYCHO catalog
78- 87 F10.4 d HJD Reduced Heliocentric Julian day (HJD-2400000)
91- 97 F7.2 km/s HRV1 ? Heliocentric Radial Velocity of Comp 1
100-105 F6.2 km/s e_HRV1 ? Heliocentric Radial Velocity error of Comp 1
109-115 F7.2 km/s HRV2 ? Heliocentric Radial Velocity of Comp 2
118-123 F6.2 km/s e_HRV2 ? Heliocentric Radial Velocity error of Comp 2
126 A1 --- l_vsini1 Limit flag on vsini1
127-131 F5.1 km/s vsini1 ? Projected rotational velocity of Comp 1
135-139 F5.1 km/s e_vsini1 ? Projected rotational velocity error 1
143 A1 --- l_vsini2 Limit flag on vsini2
144-148 F5.1 km/s vsini2 ? Projected rotational velocity of Comp 2
152-156 F5.1 km/s e_vsini2 ? Projected rotational velocity error 2
160-161 A2 --- Inst Spectrograph (1)
164-166 A3 --- Notes Individual notes (2)
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Note (1): Spectrograph as follows:
SA = SARG
AU = AURELIE
EL = ELODIE
FR = FRESCO
Note (2): Notes as follows:
SP = Small-amplitude secondary peak in the CCF. Likely SB2. See Table A1.
AC = Asymmetric CCF. Possible SB2 with blended lines. See Table A1.
c = Blended components; combined vsini.
d = RV data and orbital solution in Frasca et al. (2006, Cat. J/A+A/454/301).
* = Double-peaked CCF. Possible SB2 with blended lines. See Table A1.
T = A small-amplitude third peak in the CCF at RV=1.0km/s. SB3?
VP = Close visual pair.
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 12 A10 --- RasTyc RasTyc Name (HHMM+DDMM)
16- 30 A15 --- Name Star Name
34- 35 I2 h RAh Right ascension (J2000)
37- 38 I2 min RAm Right ascension (J2000)
40- 44 F5.2 s RAs Right ascension (J2000)
48 A1 --- DE- Declination sign (J2000)
49- 50 I2 deg DEd Declination (J2000)
52- 53 I2 arcmin DEm Declination (J2000)
55- 58 F4.1 arcsec DEs Declination (J2000)
62- 71 F10.4 d HJD Reduced Heliocentric Julian day (HJD-2400000)
74- 80 F7.2 km/s HRV1 ? Heliocentric Radial Velocity of Comp 1
83- 88 F6.2 km/s e_HRV1 ? Heliocentric RV error of Comp 1
92- 98 F7.2 km/s HRV2 ? Heliocentric Radial Velocity of Comp 2
101-106 F6.2 km/s e_HRV2 ? Heliocentric RV error of Comp 2
109-115 F7.2 km/s HRV3 ? Heliocentric Radial Velocity of Comp 3
118-123 F6.2 km/s e_HRV3 ? Heliocentric RV error of Comp 3
127 A1 --- l_vsini1 Limit flag on vsini1
128-132 F5.1 km/s vsini1 ? Projected rotational velocity of Comp 1
135-139 F5.1 km/s e_vsini1 ? Projected rotational velocity error 1
142 A1 --- l_vsini2 Limit flag on vsini2
143-147 F5.1 km/s vsini2 ? Projected rotational velocity of Comp 2
150-154 F5.1 km/s e_vsini2 ? Projected rotational velocity error 2
157 A1 --- l_vsini3 Limit flag on vsini3
158-162 F5.1 km/s vsini3 ? Projected rotational velocity of Comp 3
165-169 F5.1 km/s e_vsini3 ? Projected rotational velocity error 3
173-174 A2 --- Inst Spectrograph (1)
177-179 A3 --- Notes Individual notes (2)
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Note (1): Spectrograph as follows:
SA = SARG
AU = AURELIE
EL = ELODIE
FR = FRESCO
Note (2): Notes as follows:
a = Tertiary component much brighter than the inner binary. See Tables A1, A4
b = Close visual pair: sep=1.5", ΔV=0.6mag (Tycho-2, Hog et al.,
2000, Cat. I/259).
c = RV data and orbital solution are reported in Klutsch et al.
(2008, Cat. J/A+A/490/737)
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 12 A10 --- RasTyc RasTyc Name (HHMM+DDMM)
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 26 F5.2 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs Declination (J2000)
45- 53 A9 --- SpType ? Spectral type in MK or HD
54- 58 I5 K Teff ? Effective temperature
62- 65 I4 K e_Teff ? Effective temperature error
70- 73 F4.2 [cm/s2] logg ? Logarithm of surface gravity
78- 81 F4.2 [cm/s2] e_logg ? Error on logarithm of surface gravity
85- 89 F5.2 [Sun] [Fe/H] ? Iron abundance relative to the Sun
92- 96 F5.2 [Sun] e_[Fe/H] ? Error on iron abundance relative to the Sun
99-102 I4 0.1pm EW(Li) ? Lithium equivalent width
105-108 I4 0.1pm e_EW(Li) ? rms uncertainty on EW(Li)
112-116 I5 0.1pm EWHa ? Hα equivalent width
120-123 I4 0.1pm e_EWHa ? Hα equivalent width error
128-132 A5 --- Bin Binary flag (1)
134-138 A5 --- Inst Spectrograph (2)
142-144 A3 --- Notes Individual notes (3)
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Note (1): Binary flag as follows:
S = Single star (or single spectrum)
SB = Spectroscopic binary
SB1 = Single-lined spectroscopic binary
SB1? = Possible single-lined spectroscopic binary
SB2 = Double-lined spectroscopic binary
SB2? = Possible double-lined spectroscopic binary
Note (2): Spectrograph as follows:
SA = SARG
AU = AURELIE
EL = ELODIE
FR = FRESCO
Note (3): Notes as follows:
c = Small-amplitude secondary peak in the CCF. Likely SB2. See Table A2.
d = RV variation with respect to SACY (Torres et al. 2006,
Cat. J/A+A/460/695).
* = Double-peaked CCF. Possible SB2 with blended lines. See Table A2.
** = Close visual pair, sep=0.4". Composite spectrum: broad + narrow lines.
AC = Asymmetric CCF. Possible SB2 with blended lines. See Table A2.
UP = Close visual binary. Composite spectrum. Unreliable parameters.
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Acknowledgements:
Antonio Frasca, antonio.frasca(at)oact.inaf.it
References:
Guillout et al., Paper I 2009A&A...504..829G 2009A&A...504..829G, Cat. J/A+A/504/829
(End) Antonio Frasca [INAF-OACt, Italy], Patricia Vannier [CDS] 16-Jan-2018