Results 21 to 30 of about 4,406,721 (399)

Chemical abundances in seven metal-poor H ii regions and a determination of the primordial helium abundance [PDF]

, 2021
We conducted a long-slit spectrophotometry analysis to obtain the chemical abundances of seven metal-poor H II regions in three galaxies: UM 160, UM 420, and TOL 0513−393.
M. Valerdi, A. Peimbert, M. Peimbert
semanticscholar   +1 more source

The Open Cluster Chemical Abundances and Mapping Survey. IV. Abundances for 128 Open Clusters Using SDSS/APOGEE DR16 [PDF]

Astronomical Journal, 2020
The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to constrain key Galactic dynamical and chemical evolution parameters by the construction of a large, comprehensive, uniform, infrared-based spectroscopic data set of hundreds of open ...
J. Donor, P. Frinchaboy, K. Cunha, J. O’Connell, C. Prieto, Andres Almeida, F. Anders, R. Beaton, D. Bizyaev, J. Brownstein, R. Carrera, C. Chiappini, R. Cohen, D. A. García-Hernández, D. Geisler, S. Hasselquist, H. Jönsson, R. Lane, S. Majewski, D. Minniti, C. M. Bidin, K. Pan, A. Roman-Lopes, J. Sobeck, G. Zasowski   +24 more
semanticscholar   +1 more source

SPCANet: Stellar Parameters and Chemical Abundances Network for LAMOST-II Medium Resolution Survey [PDF]

Astrophysical Journal, 2020
The fundamental stellar atmospheric parameters (Teff and log g) and 13 chemical abundances are derived for medium-resolution spectroscopy from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Medium Resolution Survey (MRS) data sets ...
Rui Wang, A. Luo, Jian-Jun Chen, W. Hou, Shuo Zhang, Yongheng Zhao, Xiangru Li, Yong-Hui Hou   +7 more
semanticscholar   +1 more source

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

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 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

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