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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 (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:
FileName Lrecl Records Explanations
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
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
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- 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)
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.
Byte-by-byte Description of file: tablea2.dat
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)
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.
Byte-by-byte Description of file: tablea3.dat
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)
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)
Byte-by-byte Description of file: tablea4.dat
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)
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.
Acknowledgements: Antonio Frasca, antonio.frasca(at)oact.inaf.it References: Guillout et al., Paper I 2009A&A...504..829G, Cat. J/A+A/504/829
(End) Antonio Frasca [INAF-OACt, Italy], Patricia Vannier [CDS] 16-Jan-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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