Results 21 to 30 of about 4,473,250 (366)

Chemical Analysis of the Brightest Star of the Cetus II Ultrafaint Dwarf Galaxy Candidate

The Astrophysical Journal, 2023
We present a detailed chemical abundance analysis of the brightest star in the ultrafaint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra.
K. B. Webber, T. T. Hansen, J. L. Marshall, J. D. Simon, A. B. Pace, B. Mutlu-Pakdil, A. Drlica-Wagner, C. E. Martínez-Vázquez, M. Aguena, S. S. Allam, O. Alves, E. Bertin, D. Brooks, A. Carnero Rosell, J. Carretero, L. N. da Costa, J. De Vicente, P. Doel, I. Ferrero, D. Friedel, J. Frieman, J. García-Bellido, G. Giannini, D. Gruen, R. A. Gruendl, S. R. Hinton, D. L. Hollowood, K. Honscheid, K. Kuehn, J. Mena-Fernández, F. Menanteau, R. Miquel, R. L. C. Ogando, M. E. S. Pereira, A. Pieres, A. A. Plazas Malagón, E. Sanchez, B. Santiago, J. Allyn Smith, M. Smith, E. Suchyta, G. Tarle, C. To, N. Weaverdyck, B. Yanny   +44 more
doaj   +1 more source

Understanding the Chemical Evolution of Blue Edge-on Low Surface Brightness Galaxies

The Astrophysical Journal, 2023
We present a sample of 330 blue edge-on low surface brightness galaxies (ELSBGs). To understand the chemical evolution of ELSBGs, we derived the gas-phase abundance and the [ α /Fe] ratio.
Tian-wen Cao, Hong Wu, Gaspar Galaz, Venu M. Kalari, Cheng Cheng, Zi-Jian Li, Jun-feng Wang   +6 more
doaj   +1 more source

Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation

The Astrophysical Journal, 2023
Direct D-H exchange in radicals is investigated in a quasi-uniform flow employing chirped-pulse millimeter-wave spectroscopy. Inspired by the H-atom catalyzed isomerization of C _3 H _2 reported in our previous study, D-atom reactions with the propargyl (
Nureshan Dias, Ranil M. Gurusinghe, Bernadette M. Broderick, Tom J Millar, Arthur G. Suits   +4 more
doaj   +1 more source

Observing the signatures of AGB s-process nucleosynthesis in planetary nebulae: An origins story

Frontiers in Astronomy and Space Sciences, 2022
I relate an anecdotal history of the beginnings of a new initiative in studies of the chemical composition of planetary nebulae: namely, investigating abundances of elements beyond the iron-peak through infrared spectroscopy.
Harriet L. Dinerstein
doaj   +1 more source

Chemical abundances in Seyfert galaxies – X. Sulphur abundance estimates

Monthly Notices of the Royal Astronomical Society, 2023
ABSTRACT For the first time, the sulphur abundance relative to hydrogen (S/H) in the narrow-line regions of a sample of Seyfert 2 nuclei (Sy 2s) has been derived via direct estimation of the electron temperature. Narrow emission-line intensities from the Sloan Digital Sky Survey (SDSS) Data Release 17 (DR17) [in the wavelength range 3000
Oli L Dors, M Valerdi, R A Riffel, R Riffel, M V Cardaci, G F Hägele, Mark Armah, M Revalski, S R Flury, P Freitas-Lemes, E B Amôres, A C Krabbe, L Binette, A Feltre, T Storchi-Bergmann   +14 more
openaire   +3 more sources

On the Hunt for the Origins of the Orphan–Chenab Stream: Detailed Element Abundances with APOGEE and Gaia

The Astrophysical Journal, 2023
Stellar streams in the Galactic halo are useful probes of the assembly of galaxies like the Milky Way. Many tidal stellar streams that have been found in recent years are accompanied by a known progenitor globular cluster or dwarf galaxy.
Keith Hawkins, Adrian M. Price-Whelan, Allyson A. Sheffield, Aidan Z. Subrahimovic, Rachael L. Beaton, Vasily Belokurov, Denis Erkal, Sergey E. Koposov, Richard R. Lane, Chervin F. P. Laporte, Christian Nitschelm   +10 more
doaj   +1 more source

Chemical Tracing and the Origin of Carbon in the Galactic Disk

Universe, 2022
A basic problem in studies of the evolution of chemical elements in galaxies is the uncertainties in the yields of elements produced by different types of stars.
Bengt Gustafsson
doaj   +1 more source

Chemical Abundances of Main-sequence, Turnoff, Subgiant, and Red Giant Stars from APOGEE Spectra. II. Atomic Diffusion in M67 Stars [PDF]

Astrophysical Journal, 2019
Chemical abundances for 15 elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are presented for 83 stellar members of the 4 Gyr old solar-metallicity open cluster M67.
D. Souto, C. A. Prieto, C. A. Prieto, K. Cunha, M. Pinsonneault, V. Smith, R. Garcia-Dias, R. Garcia-Dias, J. Bovy, D. A. García-Hernández, D. A. García-Hernández, J. Holtzman, Julie A. Johnson, H. Jönsson, S. Majewski, M. Shetrone, J. Sobeck, O. Zamora, O. Zamora, K. Pan, C. Nitschelm   +20 more
semanticscholar   +1 more source

Chemical Abundances along the 1G Sequence of the Chromosome Maps: The Globular Cluster NGC 3201 [PDF]

Astrophysical Journal, 2019
The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the “chromosome map” (ChM) diagnostic tool that maximizes the separation between stars with different chemical
A. Marino, A. Milone, A. Sills, David Yong, A. Renzini, L. Bedin, G. Cordoni, F. D’Antona, H. Jerjen, A. Karakas, E. Lagioia, G. Piotto, M. Tailo   +12 more
semanticscholar   +1 more source

VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy [PDF]

Astronomy & Astrophysics, 2018
We present detailed chemical abundances for 99 red-giant branch stars in the centre of the Sculptor dwarf spheroidal galaxy, which have been obtained from high-resolution VLT/FLAMES spectroscopy.
V. Hill, 'Asa Sk'ulad'ottir, E. Tolstoy, K. Venn, M. Shetrone, P. Jablonka, F. Primas, G. Battaglia, T. D. Boer, P. Franccois, A. Helmi, A. Kaufer, B. Letarte, E. Starkenburg, M. Spite   +14 more
semanticscholar   +1 more source