The Stellar Population of the Thin Disk (2009)
We discuss recent observations of stars located close to the symmetry plane of the Milky Way, and examine them in the context of theories of Galaxy formation and evolution. The kinematics, ages, and...
The Discovery of Binary White Dwarfs that will Merge within 500 Myr (2009)
Kilic, Mukremin, Brown, Warren R., Prieto, Carlos Allende, Kenyon, S. J.
We present radial velocity observations of four extremely low-mass (0.2 Msol) white dwarfs. All four stars show peak-to-peak radial velocity variations of 540 - 710 km/s with 1.0 - 5.9 hr periods....
A Unique Star in the Outer Halo of the Milky Way (2009)
Lai, David K., Rockosi, Constance M., Bolte, Michael, Johnson, Jennifer A., Beers, Timothy C., Lee, Young Sun, ...
As part of a program to measure abundance ratios in stars beyond 15 kpc from the Galactic center, we have discovered a metal-poor star in the outer halo with a unique chemical signature. We...
Photometric Calibrations for 21st Century Science (2009)
Kent, Stephen, Kaiser, Mary Elizabeth, Deustua, Susana E., Smith, J. Allyn, Adelman, Saul, Allam, Sahar, ...
The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements...
An, Deokkeun, Johnson, Jennifer A., Clem, James L., Yanny, Brian, Rockosi, Constance M., Morrison, Heather L., ...
We present photometry for globular and open cluster stars observed with the Sloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellar objects with r < 22.5 mag observed by SDSS,...
The Milky Way Tomography with SDSS: II. Stellar Metallicity (2008)
Ivezic, Zeljko, Sesar, Branimir, Juric, Mario, Bond, Nicholas, Dalcanton, Julianne, Rockosi, Constance M., ...
Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F and G type main sequence stars (0.2
The sixth data release of the Sloan Digital Sky Survey (2008)
Adelman-McCarthy, Jennifer K., Agüeros, Marcel A., Allam, Sahar S., Prieto, Carlos Allende, Anderson, Kurt S. J., Anderson, Scott F., ...
This paper describes the Sixth Data Release of the Sloan Digital Sky Survey. With this data release, the imaging of the northern Galactic cap is now complete. The survey contains images and...
Roederer, Ian U., Frebel, Anna, Shetrone, Matthew D., Prieto, Carlos Allende, Rhee, Jaehyon, Gallino, Roberto, ...
We present the first detailed abundance analysis of the metal-poor giant HKII 17435-00532. This star was observed as part of the University of Texas long-term project "Chemical Abundances of Stars in...
A Reappraisal Of The Solar Photospheric C/o Ratio (2008)
Carlos Allende Prieto, David L. Lambert, Martin Asplund
Accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local thermodynamical equilibrium (LTE). We argue that...
HIPPARCOS, IUE, AND THE STELLAR CONTENT OF THE SOLAR NEIGHBOURHOOD (2007)
La combinación de flujos absolutos estelares medidos en la Tierra con las paralajes espectroscópicas del catálogo de Hipparcos, permite determinar con precisión los flujos emergentes de las...
To appear in the Astronomical Journal The Near-Ultraviolet Continuum of Late-Type Stars (2007)
Carlos Allende Prieto, David L. Lambert
Analyses of the near-ultraviolet continuum of late-type stars have led to controversial results regarding the performance of state-of-the-art model atmospheres. The release of the homogeneous IUE nal...
S 4 N: A Spectroscopic Survey of Stars in the Solar Neighborhood (2007)
Spectroscopic Survey Of, David L. Lambert, Carlos Allende Prieto, Katia Cunha
We are using the McDonald 2.7m and ESO 1.52m telescopes to obtain spectra of nearby stars at high-resolution, high S/N, and with complete optical coverage. The sample includes all stars in the...
Preprint typeset using L A T E X style emulateapj v. 04/03/99 (2007)
Carlos Allende Prieto, Ivan Hubeny, David L. Lambert
We test our knowledge of the atomic opacity in the solar UV spectrum. Using the atomic data compiled in Paper I from modern, publicly available, databases, we perform calculations that are confronted...
Preprint typeset using L A T E X style emulateapj v. 20/04/00 (2007)
The Century Survey, Warren R. Brown, Carlos Allende Prieto, Timothy C. Beers, Ronald Wilhelm, Margaret J. Geller, ...
The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (V R < 0:30 mag) as probes of the Milky Way halo. The Survey strip...
Preprint typeset using L A T E X style emulateapj v. 04/03/99 (2007)
Carlos Allende Prieto, David L. Lambert, Ivan Hubeny, Thierry Lanz
With the goal of producing a reliable set of model atoms and singly-ionized ions for use in building NLTE model atmospheres, we have combined measured energy levels, critically-compiled line...
Mon. Not. R. Astron. Soc. 000, 1{?? (2001) Printed 22 May 2002 (MN L A T E X style (2007)
Le The Isotopic, David L. Lambert, Carlos Allende Prieto
Analyses of the abundances of neutron-capture elements have led to the belief that these elements in metal-poor stars are r-process products with relative abundances closely resembling those found in...
RevMexAA (Serie de Conferencias), 10, 205-208 (2001) (2007)
Hipparcos Iue And, Carlos Allende Prieto
The spectroscopic parallaxes in the Hipparcos catalogue can be used to translate absolute stellar uxes observed at Earth to the uxes emerging at the stellar surface for nearby stars. The comparison...
Brown, Warren R., Beers, Timothy C., Wilhelm, Ronald, Prieto, Carlos Allende, Geller, Margaret J., Kenyon, Scott J., ...
We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically...
Computing Solar Absolute Fluxes (2007)
Computed color indices and spectral shapes for individual stars are routinely compared with observations for essentially all spectral types, but absolute fluxes are rarely tested. We can confront...
Constraints on Circumstellar Material Around the Type Ia Supernova 2007af (2007)
Simon, Joshua D., Gal-Yam, Avishay, Penprase, Bryan E., Li, Weidong, Quimby, Robert M., Silverman, Jeffrey M., ...
Patat et al. recently inferred the existence of circumstellar material around a normal Type Ia supernova (SN) for the first time, finding time-variable Na I D absorption lines in the spectrum of SN...
Velocities from Cross-Correlation: A Guide for Self-Improvement (2007)
The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals, and finding the location of its maximum....
The Discovery of a Companion to the Lowest Mass White Dwarf (2007)
Kilic, Mukremin, Brown, Warren R., Prieto, Carlos Allende, Pinsonneault, M. H., Kenyon, S. J.
We report the detection of a radial velocity companion to SDSS J091709.55+463821.8, the lowest mass white dwarf currently known with M~0.17Msun. The radial velocity of the white dwarf shows...
The Abundances of Oxygen and Carbon in the Solar Photosphere (2007)
A series of recent studies has placed the best estimates of the photospheric abundances of carbon and oxygen at log epsilon = 8.39 and 8.66, respectively. These values are ~ 40 % lower than earlier...
Solar Chemical Peculiarities? (2006)
Several investigations of FGK stars in the solar neighborhood have suggested that thin-disk stars with an iron abundance similar to the Sun appear to show higher abundances of other elements, such as...
The Lowest Mass White Dwarf (2006)
Kilic, Mukremin, Prieto, Carlos Allende, Brown, Warren R., Koester, D.
Extremely low mass white dwarfs are very rare objects likely formed in compact binary systems. We present MMT optical spectroscopy of 42 low mass white dwarf candidates serendipitously discovered in...
Hipparcos, IUE, and the Stellar Content of the Solar Neighbourhood (2006)
Hipparcos, IUE, and the Stellar Content of the Solar Neighbourhood
Elemental abundance survey of the galactic thick disc (2006)
Eswar Reddy, Bacham, Lambert, David L, Prieto, Carlos Allende
We have performed an abundance analysis for F- and G- dwarfs of the Galactic thick-disc component. A sample of 176 nearby (d≤ 150 pc) thick-disc candidate stars was chosen from the Hipparcos...
Abstract. The determination of chemical abundances from stellar spectra is considered a mature field of astrophysics. Digital spectra of stars are recorded and processed with standard techniques,...
Elemental Abundance Survey of The Galactic Thick Disk (2005)
Reddy, Bacham E., Lambert, David L., Prieto, Carlos Allende
[Abridged abstract] We have performed an abundance analysis for 176 F- and G- dwarfs of the Galactic thick disk component. Using accurate radial velocities combined with $Hipparcos$ astrometry,...
The Metallicity Distribution Function of the Halo of the Milky Way (2005)
Beers, Timothy C., Christlieb, Norbert, Norris, John E., Bessell, Michael S., Wilhelm, Ronald, Prieto, Carlos Allende, ...
We report on the distribution of metallicities, [Fe/H], for very metal-poor stars in the halo of the Galaxy. Although the primary information on the nature of the Metallicity Distribution Function...
Brown, Warren R., Geller, Margaret J., Kenyon, Scott J., Kurtz, Michael J., Prieto, Carlos Allende, Beers, Timothy C., ...
We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB) stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to select...
A Study of the Near-Ultraviolet Spectrum of Vega (2005)
García-Gil, Alejandro, López, Ramón J. García, Prieto, Carlos Allende, Hubeny, Ivan
UV, optical, and near-IR spectra of Vega have been combined to test our understanding of stellar atmospheric opacities, and to examine the possibility of constraining chemical abundances from...
Carlos Allende Prieto, Timothy C. Beers, Ronald Wilhelm, Heidi Jo Newberg, Constance M. Rockosi, Brian Yanny, ...
Accepted for publication in the ApJ We perform an analysis of spectra and photometry for 22,770 stars included in the third data release (DR3) of the Sloan Digital Sky Survey (SDSS). We measure...
HD 137510: An Oasis in the Brown Dwarf Desert (2004)
Endl, Michael, Hatzes, Artie P., Cochran, William D., McArthur, Barbara, Prieto, Carlos Allende, ...
Since the beginning of precise Doppler surveys, which have had stunning success in detecting extrasolar planetary companions, one surprising enigma has emerged: the relative paucity of spectroscopic...
S4N: A Spectroscopic Survey of Stars in the Solar Neighborhood (2004)
Prieto, Carlos Allende, Barklem, Paul S., Lambert, David L., Cunha, Katia
[ABRIDGED] We report the results of a high-resolution spectroscopic survey of all the stars more luminous than Mv = 6.5 mag within 14.5 pc from the Sun. We derive stellar parameters and perform a...
Carlos Allende Prieto, Martin Asplund, Peña Fabiani Bendicho
We present new observations of the center-to-limb variation of spectral lines in the quiet Sun. Our long-slit spectra are corrected for scattered light, which amounts to 4–8 % of the continuum...
Magnesium isotope ratios in Hyades stars (2003)
Yong, David, Lambert, David L., Prieto, Carlos Allende, Paulson, Diane B.
Using classical model atmospheres and an LTE analysis, Mg isotope ratios 24Mg:25Mg:26Mg are measured in 32 Hyades dwarfs covering 4000K < Teff < 5000K. We find no significant trend in any isotope...
An automated system to classify stellar spectra (2003)
Analyses of stellar spectra often begin with the determination of a number of parameters that define a model atmosphere. This work presents a prototype for an automated spectral classification system...
The Chemical Compositions of Galactic Disk F and G Dwarfs (2002)
Reddy, Bacham E., Tomkin, Jocelyn, Lambert, David L., Prieto, Carlos Allende
Photospheric abundances are presented for 27 elements from carbon to europium in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high signal-to-noise spectra. Stellar $T_{\rm...
Automated Stellar Spectral Classification and Parameterization for the Masses (2002)
Von Hippel, Ted, Prieto, Carlos Allende, Sneden, Chris
Stellar spectroscopic classification has been successfully automated by a number of groups. Automated classification and parameterization work best when applied to a homogeneous data set, and thus...
A Reappraisal of the Solar Photospheric C/O Ratio (2002)
Prieto, Carlos Allende, Lambert, David L., Asplund, Martin
Accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local thermodynamical equilibrium (LTE). We argue that...
The Isotopic Mixture of Barium in the Metal-poor Subgiant HD 140283 (2002)
Lambert, David L., Prieto, Carlos Allende
Analyses of the abundances of neutron-capture elements have led to the belief that these elements in metal-poor stars are r-process products with relative abundances closely resembling those found in...
Convective Wavelength Shifts in the Spectra of Late-Type Stars (2002)
Prieto, Carlos Allende, Lambert, David L., Tull, Robert G., MacQueen, Phillip J.
We present ultra-high resolution spectra for a set of nearby F-G-K stars on, or close to, the main sequence. The wavelength shifts of stellar lines relative to their laboratory wavelengths are...
The Spectrum of the Th-Ar Hollow-Cathode Lamp Used with the 2dcoude Spectrograph (2001)
We have produced an atlas of the Th-Ar hollow-cathode lamp used with the 2dcoude spectrograph at McDonald Observatory. The atlas covers from 3611.9 to 10596.4 A at a resolving power of 52,000. We...
Prieto, Carlos Allende, Asplund, Martin, Lopez, Ramon J. Garcia, Lambert, David L.
We have observed the spectrum of Procyon A (F5IV) from 4559 to 5780 A with a S/N of ~ 1e3 and a resolving power of 2e5. We have measured the line bisectors and relative line shifts of a large number...
Snider, Shawn, Prieto, Carlos Allende, Von Hippel, Ted, Beers, Timothy C., Sneden, Christopher, Qu, Yuan, ...
We explore the application of artificial neural networks (ANNs) for the estimation of atmospheric parameters (Teff, logg, and [Fe/H]) for Galactic F- and G-type stars. The ANNs are fed with...
The 'Forbidden' Abundance of Oxygen in the Sun (2001)
Prieto, Carlos Allende, Lambert, David L., Asplund, Martin
We reexamine closely the solar photospheric line at 6300 A, which is attributed to a forbidden line of neutral oxygen, and is widely used in analyses of other late-type stars. We use a...
Prieto, Carlos Allende, Barklem, Paul S., Asplund, Martin, Cobo, Basilio Ruiz
Spectra of late-type stars are usually analyzed with static model atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous plane-parallel or spherically symmetric geometry. The energy...
An Empirical Procedure to Estimate Distances to Stellar Clusters (2000)
A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main sequence stars with spectral...
Hipparcos, IUE, and the Stellar Content of the Solar Neighbourhood (2000)
The spectroscopic parallaxes in the Hipparcos catalogue can be used to translate absolute stellar fluxes observed at Earth to the fluxes emerging at the stellar surface for nearby stars. The...
The Near-Ultraviolet Continuum of Late-Type Stars (2000)
Prieto, Carlos Allende, Lambert, David L.
Analyses of the near-ultraviolet continuum of late-type stars have led to controversial results regarding the performance of state-of-the-art model atmospheres. The release of the homogeneous IUE...
Snider, Shawn, Qu, Yuan, Prieto, Carlos Allende, Von Hippel, Ted, Beers, Timothy C., Sneden, Chistopher, ...
New generation large-aperture telescopes, multi-object spectrographs, and large format detectors are making it possible to acquire very large samples of stellar spectra rapidly. In this context,...
Prieto, Carlos Allende, Lambert, David L.
The Hipparcos mission has made it possible to constrain the positions of nearby field stars in the colour-magnitude diagram with very high accuracy. These positions can be compared with the...
Prieto, Carlos Allende, Lopez, Ramon J. Garcia, Lambert, David L., Cobo, Basilio Ruiz
An inversion technique to recover LTE one-dimensional model photospheres for late-type stars, which was previously applied to the Sun (Allende Prieto et al. 1998), is now employed to reconstruct,...
A Consistency Test of Spectroscopic Gravities for Late-Type Stars (1999)
Prieto, Carlos Allende, Lopez, Ramon J. Garcia, Lambert, David L., Gustafsson, Bengt
Chemical analyses of late-type stars are usually carried out following the classical recipe: LTE line formation and homogeneous, plane-parallel, flux-constant, and LTE model atmospheres. We review...
Spectroscopic Observations of Convective Patterns in the Atmospheres of Metal-Poor Stars (1999)
Prieto, Carlos Allende, Lopez, Ramon J. Garcia, Lambert, David L., Gustafsson, Bengt
Convective line asymmetries in the optical spectrum of two metal-poor stars, Gmb1830 and HD140283, are compared to those observed for solar metallicity stars. The line bisectors of the most...
A catalogue of accurate wavelengths in the optical spectrum of the Sun (1998)
Prieto, Carlos Allende, Lopez, Ramon J. Garcia
We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ~ 50-150 m/s, are given for both flux...
Prieto, Carlos Allende, Cobo, Basilio Ruiz, Lopez, Ramon J. Garcia
An inversion technique has been developed to recover LTE one-dimensional model photospheres for late-type stars from very high resolution, high signal-to-noise stellar line profiles. It is...