GIANO-TNG spectroscopy of red supergiants in the young star cluster RSGC2

Origlia, L.; Oliva, E.; Maiolino, R.; Mucciarelli, A.; Baffa, C.; Biliotti, Valdemaro; Bruno, P.; Falcini, G.; Gavriousev, V.; Ghinassi, F.; Giani, E.; González, M.; Leone, F.; Lodi, M.; Massi, F.; Montegriffo, P.; Mochi, Iacopo; Pedani, M.; Rossetti, E.; Scuderi, S.; Sozzi, M.; Tozzi, A.

doi:10.1051/0004-6361/201322586

Cited by 30 publications

(51 citation statements)

References 28 publications

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“…The above spectroscopic measurements suggest either a solar or a subsolar iron abundance. This finding was reliably confirmed by Origlia et al (2013) by using high-spectral resolution (R ∼ 50 000) NIR spectra collected with GIANO at TNG. They found that the mean iron abundance of three RSGs located in the RSGC2 cluster are subsolar.…”

Section: Young Tracerssupporting

confidence: 59%

“…There is preliminary evidence that the iron abundance in the innermost Galactic regions (nuclear bulge, Galactic bar) is more metal-poor than predicted by chemical evolution models (Minchev et al 2013). Recent spectroscopic iron abundances of young stars (red supergiants, luminous blue variables, Wolf-Rayet, O-type stars) indicate either solar or subsolar abundances (Davies et al 2009a,b;Origlia et al 2013). On the other hand, chemical evolution models suggest in the same regions iron abundances larger than [Fe/H] ∼ 0.8 (Minchev et al 2013).…”

Section: Discussionmentioning

confidence: 99%

“…However, the fraction of Cepheids (Nieva & Simón-Díaz 2011;Nieva & Przybilla 2012). The green square marks the iron abundance of the two red supergiants in the Galactic center measured by Davies et al (2009a), the magenta diamonds the 26 red supergiants in the Scutum Clusters measured by Davies et al (2009b), the gray diamond the three red supergiants in the cluster RSGC2 measured by Origlia et al (2013), the red cross the two luminous blue variables (LBVs) in the Quintuplet cluster (Najarro et al 2009), and the light-blue triangle three Wolf-Rayet and two O-type stars in the Arches cluster (Martins et al 2008). The red vertical bar in the bottom right corner shows the mean uncertainty on iron abundances.…”

Section: The Iron Abundance Gradientmentioning

confidence: 99%

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On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

Genovali

Lemasle

Bono

et al. 2014

A&A

197

262

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We present homogeneous and accurate iron abundances for 42 Galactic Cepheids based on high resolution (R ∼ 38 000) high signal-to-noise ratio (S /N ≥ 100) optical spectra collected with UVES at VLT (128 spectra). The above abundances were complemented with high-quality iron abundances provided either by our group (86) or available in the literature. We were careful to derive a common metallicity scale and ended up with a sample of 450 Cepheids. We also estimated accurate individual distances for the entire sample by using homogeneous near-infrared photometry and the reddening free period-Wesenheit relations. The new metallicity gradient is linear over a broad range of Galactocentric distances (R G ∼ 5-19 kpc) and agrees quite well with similar estimates available in the literature (-0.060 ± 0.002 dex/kpc). We also uncover evidence that suggests that the residuals of the metallicity gradient are tightly correlated with candidate Cepheid groups (CGs). The candidate CGs have been identified as spatial overdensities of Cepheids located across the thin disk. They account for a significant fraction of the residual fluctuations, and also for the large intrinsic dispersion of the metallicity gradient. We performed a detailed comparison with metallicity gradients based on different tracers: OB stars and open clusters. We found very similar metallicity gradients for ages younger than 3 Gyr, while for older ages we found a shallower slope and an increase in the intrinsic spread. The above findings rely on homogeneous age, metallicity, and distance scales. Finally, by using a large sample of Galactic and Magellanic Cepheids for which accurate iron abundances are available, we found that the dependence of the luminosity amplitude on metallicity is vanishing.

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Section: Young Tracerssupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: The Iron Abundance Gradientmentioning

confidence: 99%

See 1 more Smart Citation

On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

Genovali

Lemasle

Bono

et al. 2014

A&A

197

262

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“…Interestingly, there are some intriguing young objects in the MW that might be related to the same phenomenon: a) the puzzling low-metallicity supergiants located near the end of the Galactic bar (Davies et al 2009a,b, see discussion in Genovali et al 2014 andOriglia et al 2013); b) the young [α/Fe]-enchanced stars reported by Cunha et al (2007) near the Galactic Centre, and; c) the unusual Cepheid BC Aql which, despite being young (Whitelock, priv. comm.)…”

Section: What Is Their Origin?mentioning

confidence: 96%

Young [α/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?

Chiappini

Anders

Rodrigues

et al. 2015

A&A

178

196

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We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [α/Fe] abundance ratios (as determined from APOGEE spectra) with respect to solar values. Their existence is not explained by standard chemical evolution models of the Milky Way, and shows that the chemical-enrichment history of the Galactic disc is more complex. We find similar stars in previously published samples for which isochrone-ages could be reliably obtained, although in smaller relative numbers. This might explain why these stars have not previously received attention. The young [α/Fe]-rich stars are much more numerous in the CoRoT-APOGEE (CoRoGEE) inner-field sample than in any other high-resolution sample available at present because only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [α/Fe]-rich stars are not clearly thick-disc like, despite their rather large distances from the Galactic mid-plane. Our tentative interpretation of these and previous intriguing observations in the Milky Way is that these stars were formed close to the end of the Galactic bar, near corotation -a region where gas can be kept inert for longer times than in other regions that are more frequently shocked by the passage of spiral arms. Moreover, this is where the mass return from older inner-disc stellar generations is expected to be highest (according to an inside-out disc-formation scenario), which additionally dilutes the in-situ gas. Other possibilities to explain these observations (e.g., a recent gas-accretion event) are also discussed.

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“…There are a few for the synthesis method (e.g. Önehag et al 2012;Origlia et al 2013;Rhodin 2015), and there is the large general compilation by Meléndez & Barbuy (1999). Moreover, there are line lists compiled in the NIR for the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (see e.g.…”

Section: Introductionmentioning

confidence: 99%

Near-infrared spectroscopy of the Sun and HD 20010

Andreasen

Sousa

Mena

et al. 2016

A&A

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Context. Effective temperature, surface gravity, and metallicity are basic spectroscopic stellar parameters necessary to characterize a star or a planetary system. Reliable atmospheric parameters for FGK stars have been obtained mostly from methods that rely on high resolution and high signal-to-noise optical spectroscopy. The advent of a new generation of high resolution near-infrared (NIR) spectrographs opens the possibility of using classic spectroscopic methods with high resolution and high signal-to-noise in the NIR spectral window. Aims. We compile a new iron line list in the NIR from a solar spectrum to derive precise stellar atmospheric parameters, comparable to the ones already obtained from high resolution optical spectra. The spectral range covers 10 000 Å to 25 000 Å, which is equivalent to the Y, J, H, and K-bands. Methods. Our spectroscopic analysis is based on the iron excitation and ionization balance done in local thermodynamic equilibrium. We use a high resolution and high signal-to-noise ratio spectrum of the Sun from the Kitt Peak telescope as a starting point to compile the iron line list. The oscillator strengths (log g f ) of the iron lines were calibrated for the Sun. The abundance analysis was done using the MOOG code after measuring equivalent widths of 357 solar iron lines. Results. We successfully derived stellar atmospheric parameters for the Sun. Furthermore, we analysed HD 20010, a F8IV star, from which we derived stellar atmospheric parameters using the same line list as for the Sun. The spectrum was obtained from the CRIRES-POP database. The results are compatible with the values found in the literature, confirming the reliability of our line list. However, we obtain large errors due to the quality of the data.

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GIANO-TNG spectroscopy of red supergiants in the young star cluster RSGC2

Cited by 30 publications

References 28 publications

On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk

Young [α/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?

Near-infrared spectroscopy of the Sun and HD 20010

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