A5006605823- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
National Observatory
2020-2024
Valongo Observatory
2022
This paper documents the seventeenth data release (DR17) from Sloan Digital Sky Surveys; fifth and final fourth phase (SDSS-IV). DR17 contains complete of Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal surveying over 10,000 nearby galaxies. The MaNGA Stellar Library (MaStar) accompanies this data, providing observations almost 30,000 stars through instrument during bright time. also Galactic Evolution Experiment 2 (APOGEE-2) survey publicly...
We present spectroscopic determinations of the effective temperatures, surface gravities and metallicities for 21 M-dwarfs observed at high-resolution (R $\sim$ 22,500) in \textit{H}-band as part SDSS-IV APOGEE survey. The atmospheric parameters are derived from spectral syntheses with 1-D LTE plane parallel MARCS models atomic/molecular line list, together up-to-date H$_{2}$O FeH molecular lists. Our sample range $T_{\rm eff}$ 3200 to 3800K, where eleven stars binary systems a warmer (FGK)...
We present a spectroscopic analysis of sample 48 M dwarf stars ($0.2 M_{\odot}< < 0.6 M_{\odot}$) from the Hyades open cluster using high-resolution H-band spectra SDSS/APOGEE survey. Our methodology adopts spectrum synthesis with LTE MARCS model atmospheres, along APOGEE DR17 line list, to determine effective temperatures, surface gravities, metallicities, and projected rotational velocities. The median metallicity obtained for dwarfs is [M/H]= 0.09$\pm$0.03 dex, indicating small internal...
Abstract Exoplanets hosting M dwarfs are the best targets to characterize Earth-like or super-Earth planetary atmospheres with James Webb Space Telescope (JWST). We determine detailed stellar parameters ( T eff , log g and ξ ) individual abundances of 12 elements for four cool exoplanets TOI-1685, GJ 436, 3470, TOI-2445, scheduled future observations by JWST. The analysis utilizes high-resolution near-infrared spectra from Sloan Digital Sky Survey IV APOGEE survey between 1.51 1.69 μ m....
Average magnetic field measurements are presented for 62 M-dwarf members of the Pleiades open cluster, derived from Zeeman-enhanced Fe I lines in H-band. An MCMC methodology was employed to model filling factors using SDSS-IV APOGEE high-resolution spectra, along with radiative transfer code SYNMAST, MARCS stellar atmosphere models, and DR17 spectral line list. There is a positive correlation between mean fields rotation, slow-rotator stars (Rossby number, Ro$>$0.13) exhibiting steeper slope...
ABSTRACT This paper presents chemical abundances of 12 elements (C, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe) for 80 FGK dwarfs in the Pleiades open cluster, which span a temperature range $\sim$2000 K T$_{\rm eff}$, using high-resolution (R$\sim$22 500) near-infrared SDSS (Sloan Digital Sky Survey)-IV/APOGEE (Apache Point Observatory Galactic Evolution Experiment) spectra ($\lambda$1.51–1.69 $\mu$m). Using 1D local thermodynamic equilibrium abundance analysis, we determine an overall...
Abstract We report 23 stars having Galactocentric velocities larger than 450 km s −1 in the final data release of APOGEE survey. This sample was generated using space derived by complementing high-quality radial from project Sloan Digital Sky Survey’s Data Release 17 (DR17) with distances and proper motions Gaia early 3 (eDR3). analyze observed kinematics dynamics these stars, considering different potential models for Galaxy. find that three could be unbound depending on adopted potential,...
Exoplanets hosting M dwarfs are the best targets to characterize Earth-like or super-Earth planetary atmospheres with James Webb Space Telescope (JWST). We determine detailed stellar parameters ($T_{\rm eff}$, log$g$, and $\xi$) individual abundances of twelve elements for four cool exoplanets TOI-1685, GJ 436, 3470, TOI-2445, scheduled future observations by JWST. The analysis utilizes high-resolution near-infrared spectra from SDSS-IV APOGEE survey between 1.51-1.69$\mu$. Based on 1D-LTE...
Stellar magnetic fields have a major impact on space weather around exoplanets orbiting low-mass stars. From an analysis of Zeeman-broadened Fe I lines measured in near-infrared SDSS/APOGEE spectra, mean are determined for sample 29 M dwarf stars that host closely small exoplanets. The calculations employed the radiative transfer code Synmast and MARCS stellar model atmospheres. dwarfs found to measurable ranging between $\sim$0.2 $\sim$1.5 kG, falling unsaturated regime $<$B$>$ vs P$_{\rm...
This paper presents chemical abundances of twelve elements (C, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe) for 80 FGK dwarfs in the Pleiades open cluster, which span a temperature range $\sim$2000 K T$_{\rm eff}$, using high-resolution (R$\sim$22,500) near-infrared SDSS-IV/APOGEE spectra ($\lambda$1.51--1.69 \micron). Using 1D LTE abundance analysis, we determine an overall metallicity [Fe/H]=+0.03$\pm$0.04 dex, with elemental ratios [$\alpha$/Fe]=+0.01$\pm$0.05, [odd-z/Fe]=-0.04$\pm$0.08,...
Abstract Stellar magnetic fields have a major impact on space weather around exoplanets orbiting low-mass stars. From an analysis of Zeeman-broadened Fe i lines measured in near-infrared SDSS/APOGEE spectra, mean are determined for sample 29 M dwarf stars that host closely small exoplanets. The calculations employed the radiative transfer code Synmast and MARCS stellar model atmospheres. dwarfs found to measurable ranging between ∼0.2 ∼1.5 kG, falling unsaturated regime 〈 B 〉 versus P rot...
We present a spectroscopic analysis of sample 48 M dwarf stars ($0.2 M_{\odot}< < 0.6 M_{\odot}$) from the Hyades open cluster using high-resolution H-band spectra SDSS/APOGEE survey. Our methodology adopts spectrum synthesis with LTE MARCS model atmospheres, along APOGEE DR17 line list, to determine effective temperatures, surface gravities, metallicities, and projected rotational velocities. The median metallicity obtained for dwarfs is [M/H]= 0.09$\pm$0.03 dex, indicating small...