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We present the first systematic study of lithium abundance in a chemically homogeneous sample of 27 red supergiants (RSGs) in the young Perseus complex. For these stars, accurate stellar parameters and detailed chemical abundances of iron and iron peak, CNO, alpha, light and neutron-capture elements have been already obtained by means of high resolution optical and near-infrared spectroscopy. The observed RSGs have half-solar metallicity, 10-30 Myr age, bolometric luminosities in the 10$^4$-10$^5$ L$_{\odot}$ range and likely mass progenitors in the 9-14 M$_{\odot}$ range. We detected the optical Li I doublet in eight out of the 27 observed K and M type RSGs, finding relatively low A(Li)$, Comment: Published on ApJ; 6 pages, 2 figures

We present the chemical composition of 206 red giant branch stars members of the Small Magellanic Cloud (SMC) using optical, high-resolution spectra collected with the multi-object spectrograph FLAMES-GIRAFFE at the ESO Very Large Telescope. This sample includes stars in three fields located in different positions within the parent galaxy. We analysed the main groups of elements, namely light- (Na), alpha- (O, Mg, Si, Ca, Ti), iron-peak (Sc, V, Fe, Ni, Cu) and s-process elements (Zr, Ba, La). The metallicity distribution of the sample displays a main peak around [Fe/H] ~ -1 dex and a weak metal-poor tail. However, the three fields display [Fe/H] distributions different with each other, in particular a difference of 0.2 dex is found between the mean metallicities of the two most internal fields.The fraction of metal-poor stars increases significantly (from ~1 to ~20%) from the innermost fields to the most external one, likely reflecting an age gradient in the SMC. Also, we found a hint of possible chemically/kinematic distinct substructures. The SMC stars have abundance ratios clearly distinct with respect to the Milky Way stars, in particular for the elements produced by massive stars (like Na, $\alpha$ and most iron-peak elements) that have abundance ratios systematically lower than those measured in our Galaxy. This points out that the massive stars contributed less to the chemical enrichment of the SMC with respect to the Milky Way, according to the low star formation rate expected for this galaxy. Finally, we identified small systematic differences in the abundances of some elements (Na, Ti, V and Zr) in the two innermost fields, suggesting that the chemical enrichment history in the SMC has been not uniform., Comment: 16 pages, 11 figures, 5 tables. Accepted for publication in Astronomy and Astrophysics

Context. The Perseus complex in the outer disk of the Galaxy hosts a number of clusters and associations of young stars. Gaia is providing a detailed characterization of their kinematic structure and evolutionary properties. Aims. Within the SPA Large Programme at the TNG, we secured HARPS-N and GIANO-B high-resolution optical and near-infrared (NIR) spectra of the young red supergiant (RSG) stars in the Perseus complex, in order to obtain accurate radial velocities, stellar parameters and detailed chemical abundances. Methods. We used spectral synthesis to best-fit hundreds of atomic and molecular lines in the spectra of the observed 27 RSGs. We obtained accurate estimates of the stellar temperature, gravity, micro and macro turbulence velocities and chemical abundances for 25 different elements. We also measured the $^{12}$C/$^{13}$C abundance ratio. Results. Our combined optical and NIR chemical study provides homogeneous half-solar iron with a small dispersion, about solar-scaled abundance ratios for the iron-peak, alpha and other light elements and a small enhancement of Na, K and neutron-capture elements, consistent with the thin disk chemistry traced by older stellar populations at a similar Galactocentric distance of about 10 kpc. We inferred enhancement of N, depletion of C and of the $^{12}$C/$^{13}$C isotopic abundance ratio, consistent with mixing processes in the stellar interiors during the RSG evolution., 12 pages, 7 figures, accepted for publication in Astronomy and Astrophysics

The Galactic bulge is dominated by an old, metal rich stellar population. The possible presence and the amount of a young (a few Gyr old) minor component is one of the major issues debated in the literature. Recently, the bulge stellar system Terzan 5 was found to harbor three sub-populations with iron content varying by more than one order of magnitude (from 0.2 up to 2 times the solar value), with chemical abundance patterns strikingly similar to those observed in bulge field stars. Here we report on the detection of two distinct main sequence turn-off points in Terzan 5, providing the age of the two main stellar populations: 12 Gyr for the (dominant) sub-solar component and 4.5 Gyr for the component at super-solar metallicity. This discovery classifies Terzan 5 as a site in the Galactic bulge where multiple bursts of star formation occurred, thus suggesting a quite massive progenitor possibly resembling the giant clumps observed in star forming galaxies at high redshifts. This connection opens a new route of investigation into the formation process and evolution of spheroids and their stellar content., Comment: 23 pages. 9 figures, in press on ApJ

We present the main features of SIMPLE, the Phase A study of a high resolution near IR spectrograph for the European Extreme Large Telescope and we mention a few science cases which are relevant for the study of planets in the solar system and beyond.

MOONS is a new Multi-Object Optical and Near-infrared Spectrograph selected by ESO as a third generation instrument for the Very Large Telescope (VLT). The grasp of the large collecting area offered by the VLT (8.2m diameter), combined with the large multiplex and wavelength coverage (optical to near-IR: 0.8μm - 1.8μm) of MOONS will provide the European astronomical community with a powerful, unique instrument able to pioneer a wide range of Galactic, Extragalactic and Cosmological studies and provide crucial follow-up for major facilities such as Gaia, VISTA, Euclid and LSST. MOONS has the observational power needed to unveil galaxy formation and evolution over the entire history of the Universe, from stars in our Milky Way, through the redshift desert, and up to the epoch of very first galaxies and re-ionization of the Universe at redshift z>8-9, just few million years after the Big Bang. On a timescale of 5 years of observations, MOONS will provide high quality spectra for >3M stars in our Galaxy and the local group, and for 1-2M galaxies at z>1 (SDSS-like survey), promising to revolutionise our understanding of the Universe. The baseline design consists of ~1000 fibers deployable over a field of view of ~500 square arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8μm-1.8μm and two resolution modes: medium resolution and high resolution. In the medium resolution mode (R~4,000-6,000) the entire wavelength range 0.8μm-1.8μm is observed simultaneously, while the high resolution mode covers simultaneously three selected spectral regions: one around the CaII triplet (at R~8,000) to measure radial velocities, and two regions at R~20,000 one in the J-band and one in the H-band, for detailed measurements of chemical abundances. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

The recent development of high sensitivity near infrared (NIR) spectrometers with high resolution (HR) capabilities is opening new windows in our understanding of several hot topics of modern astrophysics. This field is one of the youngest branches of astronomical research. Only few dedicated instruments are available worldwide, but with remarkably limited capabilities in terms of spectral coverage. In this paper we discuss some of the most important scientific applications of HR-NIR spectroscopy and present the design of a simple and very powerful instrument which can be easily adapted to existing 8–10 m class telescopes (e.g. VLT) and to future, larger facilities (e.g. ELT). The expected performances and limiting magnitudes are analyzed in quite some details.

From an analysis of the blue and red spectrum, and a study of the energy distribution from the optical up to the far infrared, we identify HDE 323771 as a new PMS Herbig Ae star. The P Cygni line profiles observed in the Balmer and the Fe II lines indicate the presence of a stellar wind with a velocity of 250-350 km s −1 . An upper limit of mass loss rate of 2 × 10 −10 M ○. yr −1 is derived from the observed upper limit for the Br γ luminosity

Near infrared color-magnitude diagrams and absorption spectra are powerful instruments to study the cool stellar sequences also in very reddened and crowded environments. As an example, we discuss the case of Terzan 1, a globular cluster in the Bulge of our Galaxy. By coupling near infrared photometric and spectroscopic diagnostics we perform a preliminary abundance analysis

High-resolution (HR) near-IR spectroscopy is opening new windows in our understanding of several hot topics of modern planet, stellar and extragalactic astrophysics, and it will have a huge impact in the JWST and ALMA era and beyond. The much reduced extinction at these wavelengths allows to pierce the dust embedding those objects which are heavily obscured in the optical. Moreover, at high redshifts several spectral features, commonly exploited when studying local galaxies, are shifted into the near-IR. However, despite its scientific potential, the field of HR IR spectroscopy and its related science is developing very slowly, because of the lack of optimized instruments with the necessary combination of spectral resolution and coverage.

We observed 17 AGB and post-AGB circumstellar envelopes wuth the midinfrared camera TIRCAM. The collected photometry is compared with the IRAS LRS spectra and a two color diagram for the chemical classification of the dust is developed.

The evolution of low and intermediate mass (1-8 M⊙) stars along the Asymptotic Giant Branch (AGB) is ruled by processes of mass loss, causing the whole convective envelope to be gradually ejected into space. If the stellar mass is sufficiently high (M ≥ 1.5 M⊙) the envelope itself becomes enriched in nucleosynthesis products (carbon and s-process nuclei) and the star evolves into a C-rich phase. AGB stars are hence surrounded by O-rich or C-rich envelopes, opaque at optical wavelengths, which are best studied through direct imaging in the infrared (IR).

We present deep near-IR long slit spectra of some starburst galaxies and template stellar systems (halo and LMC globular clusters of well known age and metallicity and ellipticals). Using proper IR spectral indices, which have been found to be powerful indicators of temperature in cool stars, some preliminary consideration on the dominant stellar population in the nuclear region of these galaxies are drawn.

We analyse a sample of 12 RS CVn-type systems for which accurate photometry exists, extending from optical to near-infrared and even to IRAS bandpasses in some cases. We reconstruct the energy distribution expected from the binaries, taking into account the radii and spectral types of the components, and we compare them with the observed fluxes. In five cases, an infrared excess (in the range 0.4-1.2 mag) is clearly present. Assuming that this is due to an absorbing shell, we estimate the required mass of dust, which turns out to be in the range 10 −11 -10 −14 M ○. ,corresponding to total shell masses (including gas) in the range 10 −9 -10 −12 M ○. . We suggest that the circumstellar envelopes are built by mass loss in the form of stellar winds driven by magnetic activity

The IRAS Point Source Catalog has been used to search 482 southern dark clouds for evidence of young stellar objects. Only 6 percent of the selected dark clouds have associated IRAS sources with IRAS colors typical of pre-main-sequence stars. A study of the energy distributions obtained from JHKLM photometry and IRAS flux densities give an identification of these IRAS sources. Thirteen sources have been classified as new low-mass protostellar objects and T Tauri-type stars with nebular surrounding material disks, while four IRAS sources have no evidence of near-IR excesses and appear to be similar to post T Tauri stars in which the nebular disks are probably absent or optically thin. 17 refs.

We present some results on the burst properties in star forming galaxies, using near infrared stellar features typical of red supergiants and Brackett nebular lines which trace the presence of luminous H II regions.

We used the IRAS survey to search for IR emission from 95 peculiar nebulosities with CO emission. Fifty-two IRAS sources are associated with them. We discuss the nature of the sources on the basis of their IRAS color-color diagram and of near-IR observations.

In recent years, we have been studying the energy distribution of RS CVn binaries from UV to far IR wave lengths, in order to derive general properties of the systems and to better understand their evolutionary scenario, including the history of mass loss (Busso et al., 1987, 1988). In this framework, we have so far analyzed, at different level of accuracy, a total of about 60 sources, among which 30 have been the object of detailed studies, on the basis of broad band photomertic observations from 0.35 to 60 µm, using ground-based telescopes (mainly at La Silla, ESO) and IRAS-PSC information. For these 30 binaries, the quasi-periodic variations due to the presence of photospheric spots have been carefully subtracted, to derive the energy distributions of the unperturbed systems.

Les observations IRAS des binaires du type RS CVn derivees de la version revisee du catalogue IRAS-PSC sont presentees. Ces donnees sont comparees aux sequences standards pour des etoiles normales et aux rapports de flux attendus de l'emission du corps noir; les resultats montrent que certaines sources possedent des exces IR importants tandis que d'autres sources n'en possedent pas. Cet exces, lorsqu'il existe, n'est pas correle avec le niveau d'activite ou l'etat d'evolution des sources et il est suggere que son origine repose dans la possibilite du phenomene de perte de masse pres de la sequence principale

In recent years, we have been studying the energy distribution of RS CVn binaries from UV to far IR wave lengths, in order to derive general properties of the systems and to better understand their evolutionary scenario, including the history of mass loss (Busso et al., 1987, 1988). In this framework, we have so far analyzed, at different level of accuracy, a total of about 60 sources, among which 30 have been the object of detailed studies, on the basis of broad band photomertic observations from 0.35 to 60 µm, using ground-based telescopes (mainly at La Silla, ESO) and IRAS-PSC information. For these 30 binaries, the quasi-periodic variations due to the presence of photospheric spots have been carefully subtracted, to derive the energy distributions of the unperturbed systems.

We present an empirical calibration of the Mixing-Length free parameter ${\alpha}$ based on a homogeneous Infrared database of 28 Galactic globular clusters spanning a wide metallicity range (-2.15$, Comment: 15 pages, 3 figures, ApJ in press

As part of a study aimed at determining the kinematical and chemical properties of Terzan 5, we present the first characterization of the bulge stars surrounding this puzzling stellar system. We observed 615 targets located well beyond the tidal radius of Terzan 5 and we found that their radial velocity distribution is well described by a Gaussian function peaked at =+21.0\pm4.6 km/s and with dispersion sigma_v=113.0\pm2.7 km/s. This is the one of the few high-precision spectroscopic survey of radial velocities for a large sample of bulge stars in such a low and positive latitude environment (b=+1.7{\deg}). We found no evidence for the peak at \sim+200 km/s found in Nidever et al. 2012. The strong contamination of many observed spectra by TiO bands prevented us from deriving the iron abundance for the entire spectroscopic sample, introducing a selection bias. The metallicity distribution was finally derived for a sub-sample of 112 stars in a magnitude range where the effect of the selection bias is negligible. The distribution is quite broad and roughly peaked at solar metallicity ([Fe/H]\simeq+0.05 dex) with a similar number of stars in the super-solar and in the sub-solar ranges. The population number ratios in different metallicity ranges agree well with those observed in other low-latitude bulge fields suggesting (i) the possible presence of a plateau for |b, Comment: 27 pages, 9 figures, accepted for publication by ApJ

We present new determinations of the iron abundance for 220 stars belonging to the stellar system Terzan 5 in the Galactic bulge. The spectra have been acquired with FLAMES at the Very Large Telescope of the European Southern Observatory and DEIMOS at the Keck II Telescope. This is by far the largest spectroscopic sample of stars ever observed in this stellar system. From this dataset, a subsample of targets with spectra unaffected by TiO bands was extracted and statistically decontaminated from field stars. Once combined with 34 additional stars previously published by our group, a total sample of 135 member stars covering the entire radial extent of the system has been used to determine the metallicity distribution function of Terzan 5. The iron distribution clearly shows three peaks: a super-solar component at [Fe/H]$\simeq0.25$ dex, accounting for 29% of the sample, a dominant sub-solar population at [Fe/H]$\simeq-0.30$ dex, corresponding to 62% of the total, and a minor (6%) metal-poor component at [Fe/H]$\simeq-0.8$ dex. Such a broad, multi-modal metallicity distribution demonstrates that Terzan 5 is not a genuine globular cluster but the remnant of a much more complex stellar system., Comment: 29 pages, 10 figures. Accepted for publication by ApJ

We report on the discovery of 3 metal-poor giant stars in Terzan 5, a complex stellar system in the the Galactic bulge, known to have two populations at [Fe/H]=-0.25 and +0.3. For these 3 stars we present new echelle spectra obtained with NIRSPEC at Keck II, which confirm their radial velocity membership and provide average [Fe/H]=-0.79 dex iron abundance and [alpha/Fe]=+0.36 dex enhancement. This new population extends the metallicity range of Terzan~5 0.5 dex more metal poor, and it has properties consistent with having formed from a gas polluted by core collapse supernovae., Comment: Accepted for publication on ApJ Letter

We have used optical images acquired with the Hubble Space Telescope to construct the first high-resolution extinction map in the direction of Terzan 5, a peculiar stellar system in the inner bulge of our Galaxy. The map has a spatial resolution of 8" X 8", over a total FoV of 200" X 200". The absorption clouds show a patchy structure on a typical scale of 20" and extinction variations as large as delta E(B-V) = 0.67 mag, especially in the direction of the center of the system. These correspond to an absolute color excess ranging from E(B-V)=2.15 mag, up to 2.82 mag. After the correction for differential reddening, two distinct red giant branches become clearly visible in the color magnitude diagram of Terzan 5 and they well correspond to the two sub-populations with different iron abundances recently discovered in this system., Comment: Published by the Astrophysical Journal Letters, Volume 755, Issue 2, article id. L32 (2012). 15 pages, 5 figures

We have used a sample of high-resolution spectra obtained with the multi-fiber facility FLAMES at the Very Large Telescope of the European Southern Observatory, to derive the kinematical and chemical properties of the two young Large Magellanic Cloud globular clusters NGC 2136 and NGC 2137. These two clusters represent a typical example of LMC cluster pair suspected to be bound in a binary system: indeed the cluster centers of gravity have an angular separation of less than 1.4 arcmin in the sky. The spectral analysis of seven giants in NGC 2136 and four in NGC 2137 reveals that the two clusters share very similar systemic radial velocities, namely Vrad=271.5\pm0.4 km/s (sigma=1.0 km/s) and Vrad=270.6\pm0.5 km/s (sigma=0.9 km/s) for NGC 2136 and NGC 2137, respectively, and they have also indistinguishable abundance patterns. The iron content is [Fe/H]=-0.40\pm0.01 dex (sigma=0.03 dex) for NGC 2136 and -0.39\pm0.01 dex (sigma=0.01 dex) for NGC 2137, while the [alpha/Fe] ratios are roughly solar in both clusters. These findings suggest that the two clusters are gravitationally bound and that they formed from the fragmentation of the same molecular cloud that was chemically homogeneous. This is the first firm confirmation of the binary nature of a LMC cluster pair. The most likely fate of this system is to merge into a single structure in a time-scale comparable with its orbital period., Comment: accepted for publication in Astrophysical Journal Letters

We present the chemical abundance analysis of 33 red giant stars belonging to the complex stellar system Terzan 5. We confirm the discovery of two stellar populations (Ferraro et al. 2009, Nature, 462,483) with distinct iron abundances: a relatively metal-poor component with [Fe/H]=-0.25 +/- 0.07 r.m.s., and another component with [Fe/H]=+0.27 +/- 0.04 r.m.s., exceeding in metallicity any known Galactic globular cluster. The two populations also show different [alpha/Fe] abundance ratios. The metal-poor component has an average [alpha/Fe]=+0.34 +/- 0.06 r.m.s., consistent with the canonical scenario for rapid enrichment by core collapse supernovae (SNe). The metal-rich component has [alpha/Fe]=+0.03 +/-i 0.04 r.m.s., suggesting that the gas from which it formed was polluted by both type II and type Ia SNe on a longer timescale. Neither of the two populations shows evidence of the [Al/Fe] over [O/Fe] anti-correlation, that is typically observed in Galactic globular clusters. Because these chemical abundance patterns are unique, we propose that Terzan 5 is not a true globular cluster, but a stellar system with a much more complex history of star formation and chemical enrichment.

We present an empirical method to derive photometric metallicity, reddening and distance to old stellar populations by using a few major features of the Red Giant Branch (RGB) in near IR color magnitude diagrams. We combine the observed RGB features with a set of equations linking the global metallicity [M/H] to suitable RGB parameters (colors, magnitudes and slope), as calibrated from a homogeneous sample of Galactic Globular Clusters with different metallicities. This technique can be applied to efficiently derive the main population parameters of old stellar systems, in the view of using ground-based adaptive optics and space facilities to probe the stellar content of remote galaxies., 16 pages, 4 figures, accepted for pubblication on ApJ

We have studied the chemical composition of NGC 1806, a massive, intermediate-age globular cluster that shows a double main sequence turnoff. We analyzed a sample of high-resolution spectra (secured with FLAMES at the Very Large Telescope) for eight giant stars, members of the cluster, finding an average iron content of [Fe/H] = –0.60 ± 0.01 dex and no evidence of intrinsic star-to-star variations in the abundances of light elements (Na, O, Mg, Al). Also, the (m {sub F814W}; m {sub F336W} – m {sub F814W}) color-magnitude diagram obtained by combining optical and near-UV Hubble Space Telescope photometry exhibits a narrow red giant branch, thus ruling out intrinsic variations of C and N abundances in the cluster. These findings demonstrate that NGC 1806 does not harbor chemically distinct sub-populations, at variance with what was found in old globular clusters. In turn, this indicates that the double main sequence turnoff phenomenon cannot be explained in the context of the self-enrichment processes usually invoked to explain the chemical anomalies observed in old globulars. Other solutions (i.e., stellar rotation, merging between clusters, or collisions with giant molecular clouds) should be envisaged to explain this class of globulars.