In this work, we have applied a semi-empirical spectral classification method for OB-stars using the APOGEE spectrograph to a sample of candidates in the W3–W4–W5 (W345) complexes. These massive star-forming regions span over 200 pc across the Perseus arm and have a notorious population of massive stars, from which a large fraction are members of

We report on magnetic field measurements of 157 chemically peculiar A/B stars (Ap/Bp) based on resolved, magnetically split absorption lines present in H-band spectra provided by the Sloan Digital Sky Survey (SDSS)/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. These stars represent the extreme magnetic end of a still

Context. We present a new methodology for the estimation of stellar atmospheric parameters from narrow- and intermediate-band photometry of the Javalambre Photometric Local Universe Survey (J-PLUS), and propose a method for target pre-selection of low-metallicity stars for follow-up spectroscopic studies. Photometric metallicity estimates for stars

Aims: We seek to provide abundances of a large set of light and neutron-capture elements homogeneously analyzed that cover a wide range of metallicity to constrain globular cluster (GC) formation and evolution models. Methods: We analyzed a large sample of 885 GCs giants from the SDSS IV-Apache Point Observatory Galactic Evolution Experiment

The SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey provides precise chemical abundances of 18 chemical elements for ∼176,000 red giant stars distributed over much of the Milky Way Galaxy (MW), and includes observations of the core of the Sagittarius dwarf spheroidal galaxy (Sgr). The APOGEE chemical abundance

Internal mixing on the giant branch is an important process which affects the evolution of stars and the chemical evolution of the galaxy. While several mechanisms have been proposed to explain this mixing, better empirical constraints are necessary. Here, we use [C/N] abundances in 26,097 evolved stars from the SDSS-IV/APOGEE-2 Data Release 14 to

We present [C/N]–[Fe/H] abundance trends from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment survey, Data Release 14 (DR14), for red giant branch stars across the Milky Way (3 kpc < R < 15 kpc). The carbon-to-nitrogen ratio (often expressed as [C/N]) can indicate the mass of a red giant star, from which an age can be inferred

Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July–2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA—we release

Context. The Gaia-ESO Public Spectroscopic Survey using FLAMES at the VLT has obtained high-resolution UVES spectra for a large number of giant stars, allowing a determination of the abundances of the key chemical elements carbon and nitrogen at their surface. The surface abundances of these chemical species are known to change in stars during

Kepler-730 is a planetary system hosting a statistically validated hot Jupiter in a 6.49 day orbit and an additional transiting candidate in a 2.85 day orbit. We use spectroscopic radial velocities from the APOGEE-2N instrument, Robo-AO contrast curves, and Gaia distance estimates to statistically validate the planetary nature of the additional

The large amount of chemical and kinematic information available in large spectroscopic surveys has inspired the search for chemically peculiar stars in the field. Though these metal-poor field stars ([Fe/H]

We consider a small sample of oxygen-rich, asymptotic giant branch stars in the Large Magellanic Cloud, observed by the Spitzer Space Telescope, exhibiting a peculiar spectral energy distribution, which can hardly be explained by the common assumption that dust around Asymptotic Giant Branch stars is primarily composed of silicate grains. We

We study the evolved stellar population of the galaxy Sextans A. This galaxy is one of the lowest metallicity dwarfs in which variable asymptotic giant branch stars have been detected, suggesting that little metal enrichment took place during the past history. The analysis consists in the characterization of a sample of evolved stars, based on

The parallax expansion and kinematics of a nova shell can be used to assess its age and distance, and to investigate the interaction of the ejecta with the circumstellar medium. These are key to understand the expansion and dispersal of the nova ejecta in the Galaxy. Multi-epoch images and high-dispersion spectroscopic observations of the recently

The KMnO4 oxidation reaction of C60 or C70 fullerenes in benzene solution proceeds smoothly and almost quantitatively in presence of the crown ether 18-crown-6 as phase-transfer agent. The oxidation reaction was followed spectrophotometrically from the early stages to the completion. Essentially fullerenols or polyhydroxylated fullerenes were

The carbon arc in liquid benzene produces carbon dust in addition to phenylacetyene and a number of other molecular products. The carbon dust was analyzed by Transmission Electron Microscopy (TEM), electron diffraction and Raman spectroscopy, revealing that it consists of a highly structured carbon black with high surface area. The carbon dust from

We present a catalog of stellar properties for a large sample of 6676 evolved stars with Apache Point Observatory Galactic Evolution Experiment spectroscopic parameters and Kepler asteroseismic data analyzed using five independent techniques. Our data include evolutionary state, surface gravity, mean density, mass, radius, age, and the

Context. In the era of massive spectroscopy surveys, automated stellar parameter pipelines and their validation are extremely important for an efficient scientific exploitation of the spectra. Aims: We undertake a critical and comprehensive comparison of the radial velocities and the main stellar atmosphere parameters for stars in common between

Context. Barium stars are s-process enriched giants. They owe their chemical peculiarities to a past mass transfer phase. During this phase they were polluted by their binary companion, which at the time was an asymptotic giant branch (AGB) star, but is now an extinct white dwarf. Barium stars are thus ideal targets for understanding and

We present a search for new members of the 300 km s‑1 stream (300S) near the dwarf galaxy Segue 1 using wide-field survey data. We identify 11 previously unknown bright stream members in the APOGEE-2 and SEGUE-1 and 2 spectroscopic surveys. Based on the spatial distribution of the high-velocity stars, we confirm for the first time that this