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We build and train the artificial neural network model (ANN) based on the experimental $\alpha$-decay energy ($Q_{\alpha}$) data. Besides decays between the ground states of parent and daughter nuclei, decays from the ground state of parent…

Nuclear Theory · Physics 2022-04-12 Hong-Qiang You , Zheng-Zhe Qu , Ren-Hang Wu , Hao-Ze Su , Xiao-Tao He

The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe…

Astrophysics · Physics 2009-11-13 A. Hosford , S. G. Ryan , A. E. Garcia Perez , J. E. Norris , K. A. Olive

Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median…

Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed to be unusually young. From a combined…

For studies of Galactic evolution, the accurate characterization of stars in terms of their evolutionary stage and population membership is of fundamental importance. A standard approach relies on extracting this information from stellar…

Solar and Stellar Astrophysics · Physics 2015-06-12 Aldo Serenelli , Maria Bergemann , Gregory Ruchti , Luca Casagrande

We present optical spectroscopy of two samples of GALEX grism selected Ly alpha emitters (LAEs): one at z=0.195-0.44 and the other at z=0.65-1.25. We have also observed a comparison sample of galaxies in the same redshift intervals with the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Lennox L. Cowie , Amy J. Barger , Esther M. Hu

White dwarf (WD) stars evolve simply and predictably, making them reliable age indicators. However, self-consistent validation of the methods for determining WD total ages has yet to be widely performed. This work uses 1565 wide ( > 100 au)…

Solar and Stellar Astrophysics · Physics 2022-08-17 Tyler M. Heintz , J. J. Hermes , Kareem El-Badry , Charlie Walsh , Jennifer L. van Saders , C. E. Fields , Detlev Koester

Machine Learning (ML) is becoming increasingly important in daily life. In this context, Artificial Neural Networks (ANNs) are a popular approach within ML methods to realize an artificial intelligence. Usually, the topology of ANNs is…

Neural and Evolutionary Computing · Computer Science 2022-11-15 Rune Krauss , Marcel Merten , Mirco Bockholt , Rolf Drechsler

The knowledge of the ages of stars hosting exoplanets allows us to obtain an overview on the evolution of exoplanets and understand the mechanisms affecting their life. The measurement of the ages of stars in the Galaxy is usually affected…

Earth and Planetary Astrophysics · Physics 2021-06-30 D. Nardiello , M. Deleuil , G. Mantovan , L. Malavolta , G. Lacedelli , M. Libralato , L. R. Bedin , L. Borsato , V. Granata , G. Piotto

We provide a meta-study of the statistical and individual properties of two volume-complete sets of evolved stars in the Solar Neighbourhood: (1) 852 stars from the Nearby Evolved Stars Survey (NESS), and (2) a partially overlapping set of…

This work presents a homogeneous determination of lithium abundances in a large sample of giant-planet hosting stars (N=117), and a control sample of disk stars without detected planets (N=145). The lithium abundances were derived using a…

Solar and Stellar Astrophysics · Physics 2010-11-04 L. Ghezzi , K. Cunha , V. V. Smith , R. de la Reza

We present a catalog of ~100,000 periodic variable stars in TESS FFI data among members of widely distributed moving groups identified with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to…

Solar and Stellar Astrophysics · Physics 2022-09-21 Marina Kounkel , Keivan G. Stassun , Luke G. Bouma , Kevin Covey , Lynne A. Hillenbrand , Jason Lee Curtis

Lithium abundances in a sample of halo dwarfs have been redetermined by using the new T$_{eff}$ derived by Fuhrmann et al (1994) from modelling of the Balmer lines. These T$_{eff}$ are reddening independent, homogeneous and of higher…

Astrophysics · Physics 2007-05-23 P. Molaro , F. Primas , P. Bonifacio

Stellar population synthesis models can now reproduce the photometry of old stellar systems (age $>$ 2 Gyr) in the near-infrared (NIR) bands at 3.4 and 4.6$\mu$m (WISE W1 $\&$ W2 or IRAC 1 $\&$ 2). In this paper we derive stellar…

Based on high resolution optical spectra obtained with ESPaDOnS at CFHT, we determine fundamental parameters (\Teff, R, \Lbol, \logg\ and metallicity) for 59 candidate members of nearby young kinematic groups. The candidates were identified…

Solar and Stellar Astrophysics · Physics 2015-06-22 Lison Malo , René Doyon , Gregory A. Feiden , Loïc Albert , David Lafrenière , Étienne Artigau , Jonathan Gagné , Adric Riedel

A method based on Generative Adversaria! Networks (GANs) is developed for disentangling the physical (effective temperature and gravity) and chemical (metallicity, overabundance of a-elements with respect to iron) atmospheric properties in…

Instrumentation and Methods for Astrophysics · Physics 2025-02-26 Minia Manteiga , Raúl Santoveña , Marco A. Álvarez , Carlos Dafonte , Manuel G. Penedo , Silvana Navarro , Luis Corral

Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In…

Solar and Stellar Astrophysics · Physics 2015-06-18 David R. Soderblom , Lynne A. Hillenbrand , Rob D. Jeffries , Eric E. Mamajek , Tim Naylor

Lithium is predicted, and observed, to be depleted in contracting, low-mass pre main sequence (PMS) stars. Yet these stars reach the zero age main sequence (ZAMS) with a spread in lithium abundance at a given effective temperature that is…

Solar and Stellar Astrophysics · Physics 2025-04-28 R. J. Jackson , R. D. Jeffries , E. Tognelli

This study is focused on determining the potential of using deep neural networks (DNNs) to predict the ultimate bearing capacity of shallow foundation in situations when the experimental data which may be used to train networks is scarce.…

Neural and Evolutionary Computing · Computer Science 2018-10-23 Marta Bagińska , Piotr E. Srokosz

We have determined Li abundances in 55 metal-poor (3.6 < [Fe/H] < -0.7) stars with extreme orbital kinematics. We find the Li abundance in the Li-plateau stars and examine its decrease in low-temperature, low-mass stars. The Li observations…

Astrophysics · Physics 2009-11-13 Ann Merchant Boesgaard , Alex Stephens , Constantine P. Deliyannis
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