Results 21 to 30 of about 4,372,191 (364)

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

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 Abundances in Symbiotic Stars [PDF]

The Astrophysical Journal, 2008
We have carried out a study of the chemical abundances of $^1$H, $^4$He, $^{12}$C, $^{13}$C, $^{14}$N, $^{15}$N, $^{16}$O, $^{17}$O, $^{20}$Ne and $^{22}$Ne in symbiotic stars (SSs) by means of a population synthesis code. We find that the ratios of the number of O-rich SSs to that of C-rich SSs in our simulations are between 3.4 and 24.1, depending on
Chunhua Zhu, Chunhua Zhu, Zhaojun Wang, Zhaojun Wang, Zhanwen Han, Guoliang Lü   +5 more
openaire   +3 more sources

Chemical abundances in Seyfert galaxies – VIII. Argon abundance estimates [PDF]

Monthly Notices of the Royal Astronomical Society, 2021
ABSTRACT For the first time, the argon abundance relative to hydrogen abundance (Ar/H) in the narrow line region of a sample of Seyfert 2 nuclei has been derived. In view of this, optical narrow emission line intensities of a sample of 64 local Seyfert 2 nuclei (z < 0.25) taken from Sloan Digital Sky Survey DR7 and measured by the
A F Monteiro, O L Dors
openaire   +3 more sources

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

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

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 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

Chemical Abundances in a Turbulent Medium–H2, OH+, H2O+, ArH+ [PDF]

Astrophysical Journal, 2019
Supersonic turbulence results in strong density fluctuations in the interstellar medium (ISM), which have a profound effect on the chemical structure. Particularly useful probes of the diffuse ISM are the ArH+, OH+, H2O+ molecular ions, which are highly ...
S. Bialy, D. Neufeld, M. Wolfire, A. Sternberg, B. Burkhart   +4 more
semanticscholar   +1 more source