Accès ouvert
2023
article
OpenAlex
P. Ranaivomanana, C. Johnston, P. Groot, Conny Aerts et autres
Context. Colour–magnitude diagrams reveal a population of blue (hot) sub-luminous objects with respect to the main sequence. These hot sub-luminous stars are the result of evolutionary processes that require stars to expel their obscuring, hydrogen-rich envelopes to reveal the hot helium core. …
nl, be, Afrique du Sud, de, us
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Accès ouvert
2022
article
OpenAlex
Vishnu Reddy, Michael S. P. Kelley, Jessie Dotson, Davide Farnocchia et autres
Abstract We describe results of a planetary defense exercise conducted during the close approach to Earth by the near-Earth asteroid (99942) Apophis during 2020 December–2021 March. The planetary defense community has been conducting observational campaigns since 2017 to test the operational readiness …
us, Afrique du Sud, il, es, ca, it, be, kz, kr, pl, ru, tr, br, hu, mx, de, ro, fr
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Accès ouvert
2022
article
OpenAlex
Hee-Jae Lee, M.-J. Kim, A. Marciniak, D.-H. Kim et autres
Context. The close approach of the near-Earth asteroid (99942) Apophis to Earth in 2029 will provide a unique opportunity to examine how the physical properties of the asteroid could be changed due to the Earth’s gravitational perturbation. As a result, the Republic …
kr, pl, us, gb, hu, Afrique du Sud, es, de, jp, tr
(code pays fourni par la source)