J/A+A/610/A66 Equivalent widths of 7 stars in NGC 6705 (Casamiquela+, 2018)
NGC6705 a young alpha-enhanced open cluster from OCCASO data.
Casamiquela L., Carrera R., Balaguer-Nunez L., Jordi C., Chiappini C.,
Anders F., Antoja T., Miret-Roig N., Romero-Gomez M., Blanco-Cuaresma S.,
Pancino E., Aguado D.S., del Pino A., Diaz-Perez L., Gallart C.
<Astron. Astrophys. 610, A66 (2018)>
=2018A&A...610A..66C 2018A&A...610A..66C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Abundances ; Equivalent widths
Keywords: stars: abundances -
open clusters and associations: individual: NGC 6705 (M 11)
Abstract:
The stellar [α/Fe] abundance is sometimes used as a proxy for
stellar age, following standard chemical evolution models for the
Galaxy, as seen by different observational results. In this work we
show that the Open Cluster NGC6705/M11 has a significant
α-enhancement [α/Fe]>0.1dex, despite its young age
(∼300Myr), challenging the current paradigm.{We use high resolution
(R$>65,000$) high signal-to-noise (∼70) spectra of 8 Red Clump stars,
acquired within the OCCASO survey. We determine very accurate chemical
abundances of several α elements, using an equivalent width
methodology (Si, Ca and Ti), and spectral synthesis fits (Mg and O).
We obtain [Si/Fe]=0.13±0.05, [Mg/Fe]=0.14±0.07,
[O/Fe]=0.17±0.07, [Ca/Fe]=0.06±0.05 and [Ti/Fe]=0.03±0.03. Our
results place these cluster within the group of young
[α/Fe]-enhanced field stars recently found by several authors in
the literature. The ages of our stars have an uncertainty of around
50Myr, much more precise than for field stars. By integrating the
cluster's orbit in several non-axisymmetric Galactic potentials, we
establish the M11's most likely birth radius to lie between 6.8-7.5kpc
from the Galactic center, not far from its current position. With the
robust Open Cluster age scale, our results prove that a moderate
[α/Fe]-enhancement is no guarantee for a star to be old, and
that not all α-enhanced stars can be explained with an evolved
blue straggler scenario. Based on our orbit calculations, we further
argue against a Galactic bar origin of M11.
Description:
We present a high-resolution spectroscopic study centered in the
abundances of alpha elements of 7 member stars in NGC 6705. We include
the equivalent widths of CaI, SiI and TiI lines derived for 14
spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 120 11 Details of the observed stars
table2.dat 68 79 *Equivalent widths of CaI, SiI and TiI lines
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Note on table2.dat: -99 indicates that the equivalent width of the line could
not be measured.
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See also:
J/A+A/513/A29 : RACE-OC project: M11 (NGC6705) (Messina+, 2010)
J/A+A/569/A17 : Gaia-ESO Survey: NGC6705 (Cantat-Gaudin+, 2014)
J/A+A/573/A55 : Gaia-ESO Survey: Tr 20, NGC4815, NGC6705 (Tautvaisiene+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Name Star name from WEBDA (WNNNN)
7- 8 I2 h RAh Right ascension (J2000)
10- 11 I2 min RAm Right ascension (J2000)
13- 18 F6.3 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 31 F5.2 arcsec DEs Declination (J2000)
33- 36 F4.1 mag Vmag V magnitude from literature (from literature)
38- 41 F4.2 --- Pmemb Probability of membership from proper motion
(from McNamara et al., 1977A&AS...27..117M 1977A&AS...27..117M)
43- 44 A2 --- Class1 [M SM] Classification from radial velocity (1)
45 A1 --- r_Class1 Reference for Class1 (2)
46 A1 --- --- [,]
48- 49 A2 --- Class2 [M SM] Classification from radial velocity (1)
50 A1 --- r_Class2 Reference for Class2 (2)
51 A1 --- --- [,]
53 A1 --- Class3 [M SM] Classification from radial velocity (1)
54 A1 --- r_Class3 Reference for Class3 (2)
56- 61 A6 --- Inst Instrument
63- 64 I2 --- SNR Signal-to-noise ratio of the spectrum
66- 69 I4 K Teff Effective temperature from spectroscopic
analysis
71- 73 I3 K e_Teff rms uncertainty on Teff
75- 78 F4.2 [cm/s2] logg Surface gravity from spectroscopic analysis
80- 83 F4.2 [cm/s2] e_logg rms uncertainty on logg
85- 88 F4.2 km/s vt Microturbulent velocity from EW
90- 93 F4.2 km/s e_vt rms uncertainty on vt
95- 98 F4.1 km/s RV Radial velocity from spectroscopic analysis
100-102 F3.1 km/s e_RV rms uncertainty on RV
104-107 F4.2 [-] [Fe/H] Metallicity from EW
109-112 F4.2 [-] e_[Fe/H] rms uncertainty on [Fe/H]
114-120 A7 --- Label Name of the column in table2 with equivalent
width data
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Note (1): Classification as follows:
M = member
SM = single member
Note (2): References as follows:
a = Cantat-Gaudin et al. (2014, Cat. J/A+A/569/A17) and
Tautvaisiene et al. (2015, Cat. J/A+A/573/A55),
b = Mathieu et al. (1986AJ.....92.1100M 1986AJ.....92.1100M),
c = Mermilliod et al. (2008, Cat. J/A+A/485/303)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm Lambda Wavelength of the line
10- 12 A3 --- Element Name of the chemical species
14- 19 F6.3 [-] loggf Logarithm of the oscillation strength
21- 24 F4.2 eV EP Excitation potential
26- 28 I3 0.1pm EW0660H ?=-99 Equivalent width of the spectrum W0660_HER
30- 32 I3 0.1pm EW0669H ?=-99 Equivalent width of the spectrum W0669_HER
34- 36 I3 0.1pm EW0686H ?=-99 Equivalent width of the spectrum W0686_HER
38- 40 I3 0.1pm EW0779H ?=-99 Equivalent width of the spectrum W0779_HER
42- 44 I3 0.1pm EW0779F ?=-99 Equivalent width of the spectrum W0779_FIE
46- 48 I3 0.1pm EW0916H ?=-99 Equivalent width of the spectrum W0916_HER
50- 52 I3 0.1pm EW1184H ?=-99 Equivalent width of the spectrum W1184_HER
54- 56 I3 0.1pm EW1184F ?=-99 Equivalent width of the spectrum W1184_FIE
58- 60 I3 0.1pm EW1256H ?=-99 Equivalent width of the spectrum W1256_HER
62- 64 I3 0.1pm EW1423H ?=-99 Equivalent width of the spectrum W1423_HER
66- 68 I3 0.1pm EW1423F ?=-99 Equivalent width of the spectrum W1423_FIE
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Acknowledgements:
Laia Casamiquela, laiacf(at)fqa.ub.edu
(End) Laia Casamiquela [Univ. Barcelona], Patricia Vannier [CDS] 06-Nov-2017