Start year
2010
Organizational Unit
Organizing institutions
Grants related:
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.
Members
Principal investigator
Carlos
Allende Prieto
Project staff
Prof.
Rafael
Rebolo López
Yeisson Fabián
Martínez Osorio
Thomas
Masseron
Collaborators
Andrés
Asensio Ramos
Juan
Calvo Tovar
Jorge
Casares Velázquez
Martín
López Corredoira
José Alfonso
López Aguerri
Claudio
Dalla Vecchia
Domingo Aníbal
García Hernández
Ramón
García López
Fabio
Tenegi Sanginés
FRANCISCO SHU
KITAURA JOYANES
Jonay Isai
González Hernández
Olga María
Zamora Sánchez
Pablo
Rodríguez Gil
Dr.
I. Hubeny
Dr.
D.L. Lambert
Dr.
L. Koesterke
Dr.
I. Ramirez
Dr.
M. Shetrone
Dr.
J.J. Hermes
Dr.
D. E. Winget
Dr.
B. Castanheira
Dr.
M. Asplund
Dr.
W. Brown
Dr.
M. Kilic
Dr.
S. Majewski
Dr.
R. Schiavon
Dr.
J. Holtzman
Dr.
H.G. Ludwig
Dr.
T. Beers
Dr.
V. S. Smith
Dr.
Y. Sun Lee
Dr.
M. Cropper
Dr.
D. Kawata
Dr.
M. P. Ruffoni
Dr.
J. C. Pickering
Dr.
K. Cunha
Dr.
C. Rockosi
Dr.
Andrew Cooper
Dr.
Boris Gaensicke
Results
- Complete the installation and commissioning of HORuS on GTC
- Discover two new stars with more than 100,000 times less iron than the Sun
- Complete the classification of all the APOGEE spectra with K-means
- Publish a complete collection of model stellar spectra for stars O to M
- Identify the signature of chemical diffusion in the atmospheres of the stars in the cluster M67
Scientific activity
Related publications
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Short-duration high-amplitude flares detected on the M dwarf star KIC 5474065Using data obtained during the RATS-Kepler project, we identified one short-duration flare in a 1 h sequence of ground-based photometry of the dwarf star KIC 5474065. Observations made using Gran Telescopio Canarias show that it is a star with an M4V spectral type. Kepler observations made using 1 min sampling show that KIC 5474065 exhibits largeRamsay, G. et al.
Advertised on:
92013 -
Target Selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and halo), with the principal goal of constraining dynamical and chemical evolution models of the Milky Way. APOGEE takes advantage of the reduced effects of extinction atZasowski, G. et al.
Advertised on:
102013 -
A PCA approach to stellar effective temperaturesContext. The derivation of the effective temperature of a star is a critical first step in a detailed spectroscopic analysis. Spectroscopic methods suffer from systematic errors related to model simplifications. Photometric methods may be more robust, but are exposed to the distortions caused by interstellar reddening. Direct methods are difficultMuñoz Bermejo, J. et al.
Advertised on:
52013 -
The ELM Survey. V. Merging Massive White Dwarf BinariesWe present the discovery of 17 low-mass white dwarfs (WDs) in short-period (PBrown, Warren R. et al.
Advertised on:
52013 -
Very Low Mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. V. A Low Eccentricity Brown Dwarf from the Driest Part of the Desert, MARVELS-6bWe describe the discovery of a likely brown dwarf (BD) companion with a minimum mass of 31.7 ± 2.0 M Jup to GSC 03546-01452 from the MARVELS radial velocity survey, which we designate as MARVELS-6b. For reasonable priors, our analysis gives a probability of 72% that MARVELS-6b has a mass below the hydrogen-burning limit of 0.072 M ☉, and thus it isDe Lee, Nathan et al.
Advertised on:
62013 -
A Cautionary Tale: MARVELS Brown Dwarf Candidate Reveals Itself to be a Very Long Period, Highly Eccentric Spectroscopic Stellar BinaryWe report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV)Mack, Claude E., III et al.
Advertised on:
52013 -
Very Metal-poor Stars in the Outer Galactic Bulge Found by the APOGEE SurveyDespite its importance for understanding the nature of early stellar generations and for constraining Galactic bulge formation models, at present little is known about the metal-poor stellar content of the central Milky Way. This is a consequence of the great distances involved and intervening dust obscuration, which challenge optical studiesWilson, John C. et al.
Advertised on:
42013 -
On the interpolation of model atmospheres and high-resolution synthetic stellar spectraWe present tests carried out on optical and infrared stellar spectra to evaluate the accuracy of different types of interpolation. Both model atmospheres and continuum normalized fluxes were interpolated. In the first case, we used linear interpolation, and in the second linear, cubic spline, cubic Bezier and quadratic Bezier methods. We generatedAllende-Prieto, C. et al.
Advertised on:
42013 -
Exploring the circumstellar environment of the young eruptive star V2492 CygniContext. V2492 Cyg is a young eruptive star that went into outburst in 2010. The near-infrared color changes observed since the outburst peak suggest that the source belongs to a newly defined sub-class of young eruptive stars, where time-dependent accretion and variable line-of-sight extinction play a combined role in the flux changes. Aims: InVida, K. et al.
Advertised on:
32013 -
Chemical Abundances in Field Red Giants from High-resolution H-band Spectra Using the APOGEE Spectral LinelistHigh-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory Fourier transform spectrometer, are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the Sloan Digital SkyJohnson, Jennifer A. et al.
Advertised on:
32013 -
Convective line shifts for the Gaia RVS from the CIFIST 3D model atmosphere gridContext. To derive space velocities of stars along the line of sight from wavelength shifts in stellar spectra requires accounting for a number of second-order effects. For most stars, gravitational redshifts, convective blueshifts, and transverse stellar motion are the dominant contributors. Aims: We provide theoretical corrections for the netAllende-Prieto, C. et al.
Advertised on:
22013 -
Oxygen Abundances in Nearby FGK Stars and the Galactic Chemical Evolution of the Local Disk and HaloAtmospheric parameters and oxygen abundances of 825 nearby FGK stars are derived using high-quality spectra and a non-local thermodynamic equilibrium analysis of the 777 nm O I triplet lines. We assign a kinematic probability for the stars to be thin-disk (P 1), thick-disk (P 2), and halo (P 3) members. We confirm previous findings of enhanced [ORamírez, I. et al.
Advertised on:
22013 -
Very-low-mass Stellar and Substellar Companions to Solar-like Stars from Marvels. III. A Short-period Brown Dwarf Candidate around an Active G0IV SubgiantWe present an eccentric, short-period brown dwarf candidate orbiting the active, slightly evolved subgiant star TYC 2087-00255-1, which has effective temperature T eff = 5903 ± 42 K, surface gravity log (g) = 4.07 ± 0.16 (cgs), and metallicity [Fe/H] = -0.23 ± 0.07. This candidate was discovered using data from the first two years of the MultiZhao, Bo et al.
Advertised on:
12013 -
Automated Unsupervised Classification of the Sloan Digital Sky Survey Stellar Spectra using k-means ClusteringLarge spectroscopic surveys require automated methods of analysis. This paper explores the use of k-means clustering as a tool for automated unsupervised classification of massive stellar spectral catalogs. The classification criteria are defined by the data and the algorithm, with no prior physical framework. We work with a representative set ofAllende-Prieto, C. et al.
Advertised on:
12013 -
The Metallicity Distribution Functions of SEGUE G and K Dwarfs: Constraints for Disk Chemical Evolution and FormationWe present the metallicity distribution function (MDF) for 24,270 G and 16,847 K dwarfs at distances from 0.2 to 2.3 kpc from the Galactic plane, based on spectroscopy from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey. This stellar sample is significantly larger in both number and volume than previous spectroscopicSantiago, Basílio X. et al.
Advertised on:
122012 -
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic SurveyThe Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z ~ 0.52), 102,100 new quasar spectra (median z ~ 2.32), and 90,897 new stellar spectra, along with the dataSheldon, Erin et al.
Advertised on:
122012 -
Stars and brown dwarfs in the σ Orionis cluster. III. OSIRIS/GTC low-resolution spectroscopy of variable sourcesContext. Although many studies have been performed so far, there are still dozens of low-mass stars and brown dwarfs in the young σ Orionis open cluster without detailed spectroscopic characterisation. Aims: We look for unknown strong accretors and disc hosts that were undetected in previous surveys. Methods: We collected low-resolutionCaballero, J. A. et al.
Advertised on:
102012 -
Observation and modelling of main-sequence star chromospheres - XIX. FIES and FEROS observations of dM1 starsWe present 187 high-resolution spectra for 62 different M1 dwarfs from observations obtained with the FIbre-fed Echelle Spectrograph (FIES) on the Nordic Optical Telescope (NOT) and from observations with the Fibre-fed Extended Range Echelle Spectrograph (FEROS) from the European Southern Observatory (ESO) data base. We also compiled otherHoudebine, E. R. et al.
Advertised on:
102012 -
The Milky Way's Circular-velocity Curve between 4 and 14 kpc from APOGEE dataWe measure the Milky Way's rotation curve over the Galactocentric range 4 kpcBovy, Jo et al.
Advertised on:
112012 -
The shortest period detached binary white dwarf systemWe identify SDSS J010657.39-100003.3 (hereafter J0106-1000) as the shortest period detached binary white dwarf (WD) system currently known. We targeted J0106-1000 as part of our radial velocity programme to search for companions around known extremely low-mass (ELM; ˜0.2 M&sun;) WDs using the 6.5-m Multiple Mirror Telescope. We detect peak-to-peakKilic, Mukremin et al.
Advertised on:
52011
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SEVERO OCHOA 2016 - 2019
The IAC is an internationalized Spanish research centre aiming to achieve major advances in the understanding of the laws that govern the origin and evolution of the various forms of matter/energy in the Universe. Outstanding results are expected in key areas of research such as Solar physics, Sun-Earth connections, Exoplanetary systems, Solar
Rafael
Rebolo López
