Chemical Abundances in Stars

Start year
2010
Organizational Unit

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    General
    Description

    Stellar spectroscopy allows us to determine the properties and chemical compositions of stars. From this information for stars of different ages in the Milky Way, it is possible to reconstruct the chemical evolution of the Galaxy, as well as the origin of the elements heavier than boron, created mainly in stellar interiors. It is also possible to study stellar formation, and the formation of the Galaxy, from the signature of the Galactic potential on the stellar orbits, and the distributions of mass, ages, and the abundance of heavy elements.

    Obtaining high-resolution spectra, as necessary for studies of chemical compositions, requires advanced and efficient instrumentation. This is particularly true for research that calls for large stellar samples, which demands the observation of hundreds or thousands of sources simultaneously. Efficiency requires that the data processing and analysis are performed in an automated way.

    The interpretation of spectra is based on physical models of the atmospheres of the stars, from where the light that we observe escapes the stars. The main ingredients for building such models are the fluid dynamics, and the properties of the atoms, ions, and molecules, especially regarding their interactions with the radiation coming from the stellar interior.

    Once we have a plausible model, it is possible to compute in detail how the radiation propagates through the stellar atmosphere, and the emergent spectrum, which can then be iteratively compared with the observations to refine the model.

    This project covers three different research fronts:

    - Improving model atmospheres and simulations of stellar spectra.

    - Developing tools for acquisition, reduction, and analysis of spectroscopic observations, in particular for the determination of chemical abundances in stars.

    - Designing, preparing, and executing spectroscopic studies of stars aimed at understanding a) the most relevant aspects of the physics of stellar atmospheres, b) the formation and evolution of stars, c) the origin of the chemical elements, and d) the formation, structure, and evolution of the Milky Way galaxy.

    Principal investigator
    Project staff
    Collaborators
    Dr.
    I. Hubeny
    Dr.
    B. Castanheira
    Dr.
    M. Kilic
    Dr.
    S. Majewski
    Dr.
    H.G. Ludwig
    Dr.
    M. Cropper
    Dr.
    M. P. Ruffoni
    Dr.
    J. C. Pickering
    Dr.
    K. Cunha
    Dr.
    Andrew Cooper
    Dr.
    Boris Gaensicke
    1. Complete the installation and commissioning of HORuS on GTC
    2. Discover two new stars with more than 100,000 times less iron than the Sun
    3. Complete the classification of all the APOGEE spectra with K-means
    4. Publish a complete collection of model stellar spectra for stars O to M
    5. Identify the signature of chemical diffusion in the atmospheres of the stars in the cluster M67

    Related publications

    The Pristine survey - XXII. A serendipitous discovery of an extremely Li-rich very metal-poor giant and a new method of <SUP>6</SUP>Li/<SUP>7</SUP>Li isotope measurement 2023MNRAS.526.5976S
    GTC Follow-up Observations of Very Metal-poor Star Candidates from DESI 2023ApJ...957...76A
    A Tale of Two Disks: Mapping the Milky Way with the Final Data Release of APOGEE 2023ApJ...954..124I
    The Gaia-ESO Survey: Homogenisation of stellar parameters and elemental abundances 2023A&A...676A.129H
    Decoding the compositions of four bright r-process-enhanced stars 2023MNRAS.524.5607S
    iNNterpol: High-precision interpolation of stellar atmospheres with a deep neural network using a 1D convolutional auto encoder for feature extraction 2023A&A...675A.191W
    Opacity for realistic 3D MHD simulations of cool stellar atmospheres 2023A&A...675A.160P
    Stellar Characterization and Radius Inflation of Hyades M-dwarf Stars from the APOGEE Survey 2023ApJ...951...90W
    sMILES SSPs: a library of semi-empirical MILES stellar population models with variable [α/Fe] abundances 2023MNRAS.523.3450K
    The Pristine Inner Galaxy Survey (PIGS) VII: a discovery of the first inner Galaxy CEMP-r/s star 2023MNRAS.523.2111M
    Overview of the DESI Milky Way Survey 2023ApJ...947...37C
    DAHe white dwarfs from the DESI Survey 2023MNRAS.521.4976M
    The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument 2023AJ....165..144G
    DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of Our Nearest Neighbor 2023ApJ...944....1D
    The Pristine survey - XX. GTC follow-up observations of extremely metal-poor stars identified from Pristine and LAMOST 2023MNRAS.519.5554A
    The pristine nature of SMSS 1605−1443 revealed by ESPRESSO 2023A&A...669L...4A
    Star formation in IC1396: Kinematics and subcluster structure revealed by Gaia 2023A&A...669A..22P
    The Pristine Inner Galaxy Survey (PIGS) - V. A chemo-dynamical investigation of the early assembly of the Milky Way with the most metal-poor stars in the bulge 2023MNRAS.518.4557S
    The Pristine survey - XIX. Cu and Zn abundances in metal-poor giants 2023MNRAS.518.3796C
    The Robotic Multiobject Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI) 2023AJ....165....9S
    ESPRESSO observations of HE 0107−5240 and other CEMP-no stars with [Fe/H] ≤ -4.5 2022A&A...668A..86A
    Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument 2022AJ....164..207D
    The Gaia-ESO Public Spectroscopic Survey: Motivation, implementation, GIRAFFE data processing, analysis, and final data products 2022A&A...666A.120G
    The Gaia-ESO Public Spectroscopic Survey: Implementation, data products, open cluster survey, science, and legacy,★ 2022A&A...666A.121R
    Non-LTE abundance corrections for late-type stars from 2000 Å to 3 µm. I. Na, Mg, and Al 2022A&A...665A..33L
    HD 23472: a multi-planetary system with three super-Earths and two potential super-Mercuries 2022A&A...665A.154B
    Information content of BP/RP spectra in Gaia DR3 2022MNRAS.516.3254W
    BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS) 2022ApJS..262...34H
    White Dwarf Binaries across the H-R Diagram 2022AJ....164..126A
    Absolute dimensions and apsidal motion of the eclipsing binaries V889 Aquilae and V402 Lacertae 2022A&A...665A..13B
    Photometric and spectroscopic study of the burst-like brightening of two Gaia-alerted young stellar objects 2022MNRAS.515.1774N
    HORuS transmission spectroscopy and revised planetary parameters of KELT-7 b 2022MNRAS.515.1247T
    Interpolation of spectra from 3D model atmospheres 2022A&A...661A..76B
    SEGUE-2: Old Milky Way Stars Near and Far 2022ApJS..259...60R
    Accurate Metallicities for Very Metal-poor Stars from the Ca II Infrared Triplet 2022ApJ...928..173O
    Strong CO absorption features in massive ETGs 2022MNRAS.512..378E
    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data 2022ApJS..259...35A
    Recurrent Strong Outbursts of an EXor-like Young Eruptive Star Gaia20eae 2022ApJ...927..125C
    Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey 2022ApJ...927..123S
    Fundamental physics with ESPRESSO: Precise limit on variations in the fine-structure constant towards the bright quasar HE 0515−4414 2022A&A...658A.123M

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