The RAdial Velocity Experiment: preparing the 6th Data Release chemical abundances with GAUGUIN

2017 ◽  
Vol 13 (S334) ◽  
pp. 302-303
Author(s):  
Guillaume Guiglion ◽  
Keyword(s):  
Radial Velocity ◽  
Milky Way ◽  
Chemical Elements ◽  
Elemental Abundance ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Abundance Patterns ◽  
Medium Resolution ◽  
Data Release ◽  
Future Data

AbstractIn the context of the Radial Velocity Experiment (RAVE, Steinmetz et al. 2006), we present chemical abundances derived with the pipeline GAUGUIN. Based of 520 701 RAVE stars with medium resolution (R~7 500) spectra and stellar atmospheric parameters of the fifth Data Release, the analysis is performed around the infrared Ca-triple domain for 6 chemical elements: Mg, Ni, Si, Ti, Fe and Al. We discuss here the reliability of the chemical abundances provided by GAUGUIN, and the implications for the future Data Release 6 of the RAVE Survey. We also present elemental abundance patterns of Milky Way components based of kinematical criteria.

scholarly journals The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances

2020 ◽  
Vol 160 (2) ◽  
pp. 83 ◽  
Author(s):  
Matthias Steinmetz ◽  
Guillaume Guiglion ◽  
Paul J. McMillan ◽  
Gal Matijevič ◽  
Harry Enke ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Data Release

scholarly journals Local Stellar Kinematics from RAVE data—VII. Metallicity Gradients from Red Clump Stars

2016 ◽  
Vol 33 ◽  
Author(s):  
Ö. Önal Taş ◽  
S. Bilir ◽  
G. M. Seabroke ◽  
S. Karaali ◽  
S. Ak ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Milky Way ◽  
Absolute Magnitude ◽  
Selection Effects ◽  
Stellar Kinematics ◽  
Experiment Data ◽  
Radial Gradient ◽  
Data Release ◽  
The Difference ◽  
Red Clump

AbstractWe investigate the Milky Way Galaxy’s radial and vertical metallicity gradients using a sample of 47 406 red clump stars from the RAdial Velocity Experiment Data Release 4. Distances are calculated by adopting Ks-band absolute magnitude as −1.54±0.04 mag for the sample. The metallicity gradients are calculated with their current orbital positions (Rgc and Z) and with their orbital properties (Rm and zmax): d[Fe/H]/dRgc = −0.047±0.003 dex kpc−1 for |Z| ≤ 0.5 kpc and d[Fe/H]/dRm = −0.025±0.002 dex kpc−1 for zmax ≤ 0.5 kpc. This reaffirms the radial metallicity gradient in the thin disc but highlights that gradients are sensitive to the selection effects caused by the difference between Rgc and Rm. The radial gradient is flat in the distance interval 0.5-1 kpc from the plane and then becomes positive greater than 1 kpc from the plane. The radial metallicity gradients are also eccentricity dependent. We showed that d[Fe/H]/dRm = −0.089±0.010, −0.073±0.007, −0.053±0.004 and −0.044±0.002 dex kpc−1 for ep ≤ 0.05, ep ≤ 0.07, ep ≤ 0.10 and ep ≤ 0.20 sub-samples, respectively, in the distance interval zmax ≤ 0.5 kpc. Similar trend is found for vertical metallicity gradients. Both the radial and vertical metallicity gradients are found to become shallower as the eccentricity of the sample increases. These findings can be used to constrain different formation scenarios of the thick and thin discs.

Stellar parameters with FASMA: a new spectral synthesis package

2017 ◽  
Vol 12 (S330) ◽  
pp. 271-272
Author(s):  
M. Tsantaki ◽  
D. T. Andreasen ◽  
G. D. C. Teixeira ◽  
S. G. Sousa ◽  
N. C. Santos ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Spectral Synthesis ◽  
Computational Time ◽  
Spectral Information ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Analysis Techniques ◽  
Medium Resolution ◽  
Similar Accuracy ◽  
Temperature Surface

AbstractCurrent Galactic surveys, including the Gaia mission, rely on the efficiency of the spectral analysis techniques to provide precise and accurate spectral information (i.e. effective temperature, surface gravity, metallicity, and chemical abundances) in the shortest computational time. In this work, we present a new package to preform complete spectral analyses based on the spectral synthesis technique (Tsantaki et al. 2017, submitted). We focus on deriving atmospheric parameters for FGK-type stars using both high and medium resolution (GIRAFFE) spectra. This method is implemented on the Gaia-ESO benchmark stars to confirm its validity, achieving similar accuracy for the two resolution setups.

scholarly journals The vertical metallicity gradients of mono-age stellar populations in the Milky Way thin disk

2017 ◽  
Vol 13 (S334) ◽  
pp. 281-282
Author(s):  
Ioana Ciucă ◽  
Daisuke Kawata ◽  
Jane Lin ◽  
Luca Casagrande ◽  
George Seabroke ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Milky Way ◽  
Stellar Populations ◽  
Thin Disk ◽  
Dwarf Stars ◽  
Star Forming ◽  
Data Release ◽  
The Cross

AbstractWe investigate the vertical metallicity gradients of five mono-age stellar populations between 0 and 11 Gyr for a sample of 18 435 dwarf stars selected from the cross-matched Tycho-Gaia Astrometric Solution (TGAS) and RAdial Velocity Experiment (RAVE) Data Release 5. We find a correlation between the vertical metallicity gradients and age, with no vertical metallicity gradient in the youngest population and an increasingly steeper negative vertical metallicity gradient for the older stellar populations. We also find that the intrinsic dispersion in metallicity increases steadily with age. Our results are consistent with a scenario that thin disk stars formed from a flaring thin star-forming disk.

scholarly journals Chemical Abundances in the Sagittarius Galaxy: Terzan 7

2005 ◽  
Vol 13 ◽  
pp. 210-210
Author(s):  
Gražina Tautvaišienė ◽  
George Wallerstein ◽  
Doug Geisler ◽  
Guillermo Gonzalez ◽  
Corinne Charbonnel
Keyword(s):  
High Resolution ◽  
Chemical Elements ◽  
Elemental Abundance ◽  
Close Similarity ◽  
Host Galaxy ◽  
Red Giants ◽  
Chemical Abundances ◽  
The Mean

AbstractAbundances of 21 chemical elements have been determined in three red giants in Terzan 7 using high-resolution spectra obtained with the UVES spectrograph on the ESO 8.2 m Kueyen telescope. The mean [Fe/H]= –0.61 ±0.07. The relative elemental abundance ratios indicate a close similarity of Terzan 7 to its host galaxy.

scholarly journals RAVE-Gaia and the impact on Galactic archeology

2017 ◽  
Vol 12 (S330) ◽  
pp. 176-180
Author(s):  
Andrea Kunder
Keyword(s):  
Radial Velocity ◽  
Effective Temperature ◽  
Milky Way ◽  
Radial Velocities ◽  
Surface Gravity ◽  
Individual Stars ◽  
Dynamic Analyses ◽  
Data Release ◽  
The Impact ◽  
Temperature Surface

AbstractThe new data release (DR5) of the RAdial Velocity Experiment (RAVE) includes radial velocities of 520,781 spectra of 457,588 individual stars, of which 215,590 individual stars are released in the Tycho-Gaia astrometric solution (TGAS) in Gaia DR1. Therefore, RAVE contains the largest TGAS overlap of the recent and ongoing Milky Way spectroscopic surveys. Most of the RAVE stars also contain stellar parameters (effective temperature, surface gravity, overall metallicity), as well as individual abundances for Mg, Al, Si, Ca, Ti, Fe, and Ni. Combining RAVE with TGAS brings the uncertainties in space velocities down by a factor of 2 for stars in the RAVE volume – 10 km s−1 uncertainties in space velocities are now able to be derived for the majority (70%) of the RAVE-TGAS sample, providing a powerful platform for chemo-dynamic analyses of the Milky Way. Here we discuss the RAVE-TGAS impact on Galactic archaeology as well as how the Gaia parallaxes can be used to break degeneracies within the RAVE spectral regime for an even better return in the derivation of stellar parameters and abundances.

scholarly journals White dwarfs in the Gaia era

2017 ◽  
Vol 12 (S330) ◽  
pp. 317-320
Author(s):  
P.-E. Tremblay ◽  
N. Gentile-Fusillo ◽  
J. Cummings ◽  
S. Jordan ◽  
B. T. Gänsicke ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Main Sequence ◽  
Milky Way ◽  
Mass Function ◽  
Initial Mass Function ◽  
Sequence Evolution ◽  
Atmospheric Parameters ◽  
Stellar Formation ◽  
Formation History ◽  
Data Release

AbstractThe vast majority of stars will become white dwarfs at the end of the stellar life cycle. These remnants are precise cosmic clocks owing to their well constrained cooling rates. Gaia Data Release 2 is expected to discover hundreds of thousands of white dwarfs, which can then be observed spectroscopically with WEAVE and 4MOST. By employing spectroscopically derived atmospheric parameters combined with Gaia parallaxes, white dwarfs can constrain the stellar formation history in the early developing phases of the Milky Way, the initial mass function in the 1.5 to 8 M⊙ range, and the stellar mass loss as well as the state of planetary systems during the post main-sequence evolution.

scholarly journals The Milky Way evolution under the RAVE perspective

2015 ◽  
Vol 11 (S317) ◽  
pp. 320-323
Author(s):  
Georges Kordopatis ◽  
Keyword(s):  
Radial Velocity ◽  
Milky Way ◽  
Solar Neighbourhood ◽  
Low Mass Stars ◽  
Medium Resolution ◽  
Low Mass

AbstractThe RAdial Velocity Experiment (RAVE) collected from 2003 to 2013 medium resolution spectra for 5ċ105 low-mass stars of our Galaxy, improving our understanding of the Milky Way evolution and of its properties outside the Solar neighbourhood. This proceeding gives an overview of RAVE results obtained in the last two years.

scholarly journals A Spectroscopic Study of Barium Stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 425-426
Author(s):  
G. Q. Liu ◽  
Y. C. Liang ◽  
L. Deng
Keyword(s):  
Neutron Capture ◽  
Binary Systems ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Agb Stars ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Capture Process ◽  
Abundance Patterns ◽  
Process Elements

AbstractWe present an analysis of eight barium stars, providing their atmospheric parameters (Teff, log g, [Fe/H], ξt) and chemical abundances, based on the high signal-to-noise ratio and high resolution Echelle spectra. The s-process elements Y, Zr, Ba, La, Eu show obvious overabundance relative to the Sun. And Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni show comparable abundances to the Solar ones. The results of theoretical model of wind accretion for binary systems can explain the observed abundance patterns of the neutron capture process elements in these Ba stars, which means that their overabundant heavy-elements could be caused by accreting the ejecta of AGB stars, the progenitors of the present white dwarf companions in the binary systems.

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