Results 41 to 50 of about 4,473,250 (366)

Neon and Sulfur Abundances of Planetary Nebulae in the Magellanic Clouds [PDF]

, 2007
The chemical abundances of neon and sulfur for 25 planetary nebulae (PNe) in the Magellanic Clouds are presented. These abundances have been derived using mainly infrared data from the Spitzer Space Telescope.
Aller L. H., de Graauw T., Feldman U., Fluks M. A., Grevesse N., J. Bernard‐Salas, J. R. Houck, Monk D. J., P. W. Morris, Pena M., S. Gutenkunst, S. R. Pottasch, Zijlstra A. A.   +12 more
core   +4 more sources

Constraining cosmic scatter in the Galactic halo through a differential analysis of metal-poor stars [PDF]

, 2017
© ESO 2017.Context. The chemical abundances of metal-poor halo stars are important to understanding key aspects of Galactic formation and evolution. Aims.
Amanda Karakas, Andrievsky, Andrievsky, Andrievsky, Andrievsky, Andrievsky, Aoki, Aoki, Arnone, Asplund, Asplund, Audouze, Baumueller, Baumueller, Bensby, Bergemann, Bergemann, Biazzo, Boesgaard, Bonifacio, Bonifacio, Busso, Busso, Carlos, Caughlan, Cayrel, Cescutti, Chiaki Kobayashi, Chiappini, Chieffi, Civitarese, Coc, Coc, Coc, Cohen, Cowan, Cyburt, Eggen, Ferraro, Ferraro, Fishlock, François, Frischknecht, Fu, Gustafsson, Hampel, Hannaford, Hansen, Hartog, Heger, Henrique Reggiani, Herwig, Hollek, Hou, Iocco, Jacobson, Ji, Jorge Meléndez, Karakas, Karakas, Keller, Kim, Kobayashi, Kobayashi, Kobayashi, Kohri, Lai, Lawler, Lind, Lind, Liu, Liu, Maeda, McCrea, McWilliam, Meléndez, Meléndez, Meléndez, Meléndez, Meyer, Meynet, Monroe, Nissen, Nissen, Nissen, Nomoto, Norris, Norris, O’Malley, Pignatari, Placco, Placco, Placco, Pllumbi, Ramírez, Ramírez, Ramírez, Ramírez, Ramírez, Ramírez, Reggiani, Richard, Roederer, Ryan, Ryan, Ryan, Salvati, Santucci, Scholz, Schuster, Searle, Shigeyama, Sills, Sitnova, Sneden, Spina, Spite, Spite, Spite, Suda, Suda, Thielemann, Tucci Maia, Tucci Maia, Umeda, Vinicius Placco, Wood, Yamada, Yi, Yong, Zhao, Önehag   +131 more
core   +3 more sources

Chemical Abundances of New Member Stars in the Tucana II Dwarf Galaxy [PDF]

, 2018
We present chemical abundance measurements for seven stars with metallicities ranging from Fe/H] = −3.3 to [Fe/H] = −2.4 in the Tucana II ultra-faint dwarf galaxy (UFD), based on high-resolution spectra obtained with the MIKE spectrograph on the 6.5 m ...
A. Chiti, A. Frebel, A. Ji, H. Jerjen, Dongwon Kim, J. Norris   +5 more
semanticscholar   +1 more source

Chemical abundances and radial velocities in the extremely metal-poor galaxy DDO 68 [PDF]

Monthly notices of the Royal Astronomical Society, 2018
We present chemical abundances and radial velocities of six HII regions in the extremely metal-poor star-forming dwarf galaxy DDO 68. They are derived from deep spectra in the wavelength range 3500 - 10,000 {\AA}, acquired with the Multi Object Double ...
F. Annibali, V. L. Torre, M. Tosi, C. Nipoti, F. Cusano, A. Aloisi, M. Bellazzini, L. Ciotti, A. Marchetti, M. Mignoli, D. Romano, E. S. I. D. A. E. S. Spazio, Bologna, Italy, D. Astronomia, U. Bologna, Space Telescope Science Institute, Baltimore., Usa, I. D. F. Cosmica, Milano   +20 more
semanticscholar   +1 more source

Chemical Abundances of Main-sequence, Turnoff, Subgiant, and Red Giant Stars from APOGEE Spectra. I. Signatures of Diffusion in the Open Cluster M67 [PDF]

, 2018
Detailed chemical abundance distributions for 14 elements are derived for eight high-probability stellar members of the solar metallicity old open cluster M67 with an age of ∼4 Gyr.
D. Souto, K. Cunha, V. Smith, C. Prieto, C. Prieto, D. A. García-Hernández, D. A. García-Hernández, M. Pinsonneault, Parker H. Holzer, P. Frinchaboy, J. Holtzman, J. A. Johnson, H. Jönsson, S. Majewski, M. Shetrone, J. Sobeck, G. Stringfellow, J. Teske, O. Zamora, O. Zamora, G. Zasowski, R. Carrera, K. Stassun, J. Fernández-Trincado, J. Fernández-Trincado, S. Villanova, D. Minniti, F. Santana   +27 more
semanticscholar   +1 more source

Chemical Abundances in Galactic Bulge Pn [PDF]

Symposium - International Astronomical Union, 1993
We present abundance determinations, in particular of carbon, and C/O ratios, for 11 Galactic bulge planetary nebulae (PN) based on our low resolution UV data from IUE observations and optical spectrophotometry from the Anglo-Australian Telescope. We compare the observed abundances with those predicted by dredge-up theory for the high metallicity ...
N. A. Walton, M. J. Barlow, R. E. S. Clegg   +2 more
openaire   +1 more source

Li-rich Giants Identified from LAMOST DR8 Low-resolution Survey

The Astronomical Journal, 2023
A small fraction of giants possess photospheric lithium (Li) abundance higher than the value predicted by the standard stellar evolution models, and the detailed mechanisms of Li enhancement are complicated and lack a definite conclusion.
Beichen Cai, Xiaoming Kong, Jianrong Shi, Qi Gao, Yude Bu, Zhenping Yi   +5 more
doaj   +1 more source

Chemical Abundances of Hydrostatic and Explosive Alpha-elements in Sagittarius Stream Stars [PDF]

, 2018
We analyze chemical abundances of stars in the Sagittarius (Sgr) tidal stream using high-resolution Gemini+GRACES spectra of 42 members of the highest surface-brightness portions of both the trailing and leading arms.
J. Carlin, Allyson A. Sheffield, K. Cunha, V. Smith   +3 more
semanticscholar   +1 more source

JINAbase—A Database for Chemical Abundances of Metal-poor Stars [PDF]

Astrophysical Journal Supplement Series, 2017
Reconstructing the chemical evolution of the Milky Way is crucial for understanding the formation of stars, planets, and galaxies throughout cosmic time.
Abdu Abohalima, A. Frebel
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
Lu, Guoliang, Zhu, Chunhua, Han, Zhanwen, Wang, Zhaojun   +3 more
openaire   +2 more sources