Results 21 to 30 of about 207,702 (293)

The atmosphere of supergiant star HD 7927 (F0 Ia): Fundamental parameters and chemical composition [PDF]

Serbian Astronomical Journal
The atmosphere of supergiant star HD 7927 (F0 Ia) is investigated by the method of atmospheric model. The effective temperature and surface gravity are determined by comparing the observed and theoretical values of photometrical indices ...
Samedov Z.A., Hajiyeva G.M.
doaj   +1 more source

Intriguing Revelations from Lithium, Beryllium, and Boron

The Astrophysical Journal, 2023
This is a report on some highlights of research on the rare light elements, lithium (Li), beryllium (Be), and boron (B), that were presented at my Henry Norris Russell Lecture in 2020 January.
Ann Merchant Boesgaard
doaj   +1 more source

Ionization in atmospheres of brown dwarfs and extrasolar planets. i. The role of electron avalanche [PDF]

, 2010
Brown dwarf and extrasolar planet atmospheres form clouds which strongly influence the local chemistry and physics. These clouds are globally neutral obeying dust-gas charge equilibrium which is, on short timescales, inconsistent with the observation of ...
D. A. Diver, Witte, S., Diver, D.A., S. Witte, Helling, C., Jardine, M., M. Jardine, Helling, Christiane, Diver, D. A., Ch. Helling   +9 more
core   +1 more source

The influence of galactic cosmic rays on ion-neutral hydrocarbon chemistry in the upper atmospheres of free-floating exoplanets [PDF]

, 2014
The authors highlight financial support of the European Community under the FP7 by an ERC starting grant.Cosmic rays may be linked to the formation of volatiles necessary for prebiotic chemistry.
P. B. Rimmer, C. Bilger, Rimmer, P.B., Helling, C., Bilger, C., Ch. Helling   +5 more
core   +1 more source

Pulsating Stellar Atmospheres [PDF]

Symposium - International Astronomical Union, 1997
We review the basic concepts, present state of theoretical models, and the future prospects for theory and observations of pulsating stellar atmospheres. Our emphasis is on radially pulsating cool stars, which dynamic atmospheres provide a general example for the differences with standard static model atmospheres.
openaire   +3 more sources

Lithium in Turnoff Stars in the Globular Cluster M5: A Quest for Primordial Lithium

The Astrophysical Journal, 2023
The light element lithium is formed by nucleosynthesis during the Big Bang. Its abundance can help to define the parameters of the early Universe. To find this primordial value, it is necessary to determine Li abundances in the oldest stars because it is
Ann Merchant Boesgaard, Constantine P. Deliyannis   +1 more
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A study of U Aquarii and the nucleosynthesis of neutrons and S-process elements in evolved stars of low mass [PDF]

, 2014
The origin of the extreme hydrogen deficiency observed in the R Coronae Borealis (RCrB) stars remains poorly understood. A likely mechanism for producing this deficiency is one whereby the original hydrogen envelope of the star is engulfed and ...
Malaney, Robert A.
core   +2 more sources

A ring system detected around the Centaur (10199) Chariklo [PDF]

, 2014
Hitherto, rings have been found exclusively around the four giant planets in the Solar System1. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies.
Vanzi, L., Frank, N.R., Spagnotto, Julio, H. Monteiro, Harpsøe, Kennet Bomann West, J. Lecacheux, M. Emilio, Braga-Ribas, Felipe, F. Roques, M. Gillon, E. Jehin, Vanzi, Leonardo, Machado, D. I., Roques, Françoise, Lellouch, Emmanuel, Vachier, Frédéric, R. Sfair, Almenares, L., Colazo, C., Colas, F., D. G. Lambas, Jørgensen, U., Jehin, E., Lemos, Pablo, J. L. Ortiz, J. B. Haislip, J. P. Moore, Gil Hutton, Ricardo Alfredo, Wang, X.-b., Gil-Hutton, Ricardo, Ivarsen, Kevin, Opitom, C., R. Melia, Ortiz, J. L., Moore, J., A. Ceretta, Harpsoe, K., Schneiter, E. M., Lambas, Diego García, Lacluyze, A.P., Braga-Ribas, F., Lorenzini, L., Schneiter, E.M., B. Sicardy, Gu, S.-h., L. Almenares, Melia, R., L. Maquet, Reichart, Daniel E., LaCluyze, A. P., Haislip, J. B., Ivarsen, K. M., L. Vanzi, Benedetti-Rossi, G., R. G. Sandness, Haislip, J.B., Garcia Lambas, Diego Rodolfo, G. Tancredi, Perez, V., J. Spagnotto, Sicardy, Bruno, Wang, Xiaobin, Martinez, N., Colas, François, P. Kervella, P. Lemos, Benedetti-Rossi, Gustavo, C. Colazo, Gil-Hutton, R., LaCluyze, A., Tancredi, G., Frank, N. R., Gu, S. -H., Snodgrass, Colin, Maury, A., Gillon, Michaël, Gomes, A. Ramos, Manfroid, Jean, MacHado, D.I., Gomes Jr., A., F. Char, Widemann, Thomas, Ceretta, Alberto, Maury, A. J., M. Dominik, Schneiter, E., Tancredi, Gonzalo, Char, F., Opitom, Cyrielle, Gillon, M., Brage-Ribas, F., Roland, S., Lacluyze, Aaron P., Moutamid, M. El, Lambas, D., Roques, F., Ceretta, A., Manfroid, J., Ligier, N., Lecacheux, J., V. Perez, Monteiro, H., Lambas, D. G., S. Roland, U. G. Jørgensen, El Moutamid, Maryame, Harpsøe, Kennet, Machado, D., J. Pollock, Leiva, R., R. Gil-Hutton, Colazo, Carlos, Benedetti Rossi, G., Mehret, Leandro Cesar, Braga Ribas, F., Frank, Nathan R., El Moutamid, M., Assafin, Marcelo, A. Ramos Gomes, Emilio, M., Gu, S., Jorgensen, U. G., Gu, Shenghong, N. Ligier, M. Rabus, Camargo, Julio, L. Lorenzini, Rabus, Markus, Skottfelt, Jesper Mirsa, Camargo, J. I. B., Sicardy, B., Skottfelt, J., Vieira-Martins, R., Lemos, P., Moore, Justin, Char, Farid, Moore, J.P., Rabus, M., Roig, F., Ivarsen, K., Vachier, F., Sandness, R. G., Wang, X. -B., Camargo, J., K. M. Ivarsen, Haislip, Joshua, Skottfelt, Jesper, Assafin, M., Lellouch, E., Vierira-Martins, R., Sandness, R.G., Vieira Martins, R., Ivarsen, K.M., Reichart, D.E., D. I. Machado, Gomes, A. R., J. Manfroid, Camargo, J., I B, Sfair, R. [UNESP], E. Lellouch, Frank, N., N. Morales, Reichart, D., F. Colas, Ortiz, J.L., X.-b. Wang, C. Opitom, S.-h. Gu, F. Braga-Ribas, Emilio, Marcelo, N. R. Frank, K. Harpsøe, Roland, Santiago, Vieira-Martins, Roberto, J. Skottfelt, Harpsøe, K., Jorgensen, U., N. Martinez, Moore, J. P., Ligier, Nicolas, J. I. B. Camargo, Pollock, J., Camargo, J.I.B., Reichart, D. E., Melia, Raul Roberto, Lecacheux, Jean, Jørgensen, Uffe Gråe, C. Snodgrass, Jørgensen, U.G., G. Benedetti-Rossi, Haislip, J., M. El Moutamid, Camargo, J.,, Sfair, R., Maquet, L., Sfair, Rafael, Mehret, L., Duffard, R., Jørgensen, U. G., Dominik, M., Duffard, R,, Kervella, Patrick, Dominik, Martin, R. Vieira-Martins, Snodgrass, C., Spagnotto, J., Widemann, T., Duffard, René, A. P. LaCluyze, Pollock, Joseph, E. M. Schneiter, Maquet, Lucie, Sandness, R., Morales, N., Kervella, P., Wang, X., L. Mehret, A. Maury, Ramos Gomes, A., F. Vachier, Jehin, Emmanuel, T. Widemann, R. Duffard, Schneiter, E. Matías, F. Roig, R. Leiva, M. Assafin, Ortiz, J., D. E. Reichart, Ortiz, José Luis, Morales, Nicolás, Duffard, René D., Gomes, A. Ramos, Jr.   +232 more
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The Influence of Chemi-Ionization and Recombination Processes on Spectral Line Shapes in Stellar Atmospheres

Open Astronomy, 2011
The chemi-ionization processes in atom - Rydberg atom collisions, as well as the corresponding chemi-recombination processes, are considered as factors of influence on the atom exited-state populations in weakly ionized layers of stellar atmospheres. The
Mihajlov Anatolij A., Ignjatović Ljubinko M., Srécković Vladimir A., Dimitrijević Milan S.   +3 more
doaj   +1 more source

New Methods in Modeling of Hot Stellar Atmospheres

Open Astronomy, 2013
In the present study we had three main aims. First to study the possibility of reducing the initial model atmosphere data to short analytical polynomials.
Sapar A., Poolamäe R., Sapar L.
doaj   +1 more source