Results 11 to 20 of about 720,446 (211)

Wolf-Rayet Stars

open access: yes, 2015
Nearly 150 years ago, the French astronomers Charles Wolf and Georges Rayet described stars with very conspicuous spectra that are dominated by bright and broad emission lines. Meanwhile termed Wolf-Rayet Stars after their discoverers, those objects turned out to represent important stages in the life of massive stars. As the first conference in a long
Hamann, Wolf-Rainer (Prof. Dr.)   +2 more
openaire   +2 more sources

Studying the Interstellar Medium of H II/BCD Galaxies Using IFU Spectroscopy

open access: yesAdvances in Astronomy, 2013
We review the results from our studies, and previous published work, on the spatially resolved physical properties of a sample of H ii/BCD galaxies, as obtained mainly from integral-field unit spectroscopy with Gemini/GMOS and VLT/VIMOS. We confirm that,
Patricio Lagos, Polychronis Papaderos
doaj   +2 more sources

Wolf-Rayet stars

open access: yes
Massive Wolf-Rayet (WR) stars comprise a spectroscopic class characterized by high temperatures (Teff > ~30 kK) and powerful and rapid stellar winds. Hydrogen-rich WR stars represent the most massive stars in existence (M > ~100 Msun), while classical WR stars are hydrogen-depleted, evolved massive stars which probe the final evolutionary stages ...
Shenar, Tomer
core   +4 more sources

Laboratory exploration of mineral precipitates from Europa's subsurface ocean. [PDF]

open access: yesJ Appl Crystallogr, 2021
Precipitation experiments from a model Europan ocean solution subjected to fast and slow freezing suggest that the highly hydrated Na–Mg sulfate phase Na2Mg(SO4)2·16H2O is one of the lowest‐temperature mineral phases likely to be stable on Europa's surface and may therefore be astrobiologically significant.The precipitation of hydrated phases from a ...
Thompson SP   +5 more
europepmc   +2 more sources

On the application of machine learning in astronomy and astrophysics: A text‐mining‐based scientometric analysis

open access: yesWIREs Data Mining and Knowledge Discovery, Volume 12, Issue 5, September/October 2022., 2022
This work presents a text‐mining‐based scientometric analysis of the scientific output in the last three decades regarding the use of artificial intelligence and machine learning in the fields of astronomy and astrophysics. Abstract Since the beginning of the 21st century, the fields of astronomy and astrophysics have experienced significant growth at ...
José‐Víctor Rodríguez   +2 more
wiley   +1 more source

SARS‐CoV‐2 infection and venous thromboembolism after surgery: an international prospective cohort study

open access: yesAnaesthesia, Volume 77, Issue 1, Page 28-39, January 2022., 2022
Summary SARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri‐operative or prior SARS‐CoV‐2 were at further increased risk of venous ...
COVIDSurg Collaborative   +16163 more
wiley   +1 more source

Application of Spectroscopy Technology in Nanomaterials in Identification of Chinese Paintings

open access: yesJournal of Nanomaterials, Volume 2022, Issue 1, 2022., 2022
The authenticity of calligraphy and painting is an important knowledge in the collection and research of Chinese painting and calligraphy. The identification of folk painting and calligraphy is usually conducted by experts and scholars engaged in cultural relics, archaeology, painting and calligraphy, and ancient buildings.
Lili Bai   +3 more
wiley   +1 more source

Optically thick clumps: not the solution to the Wolf-Rayet wind momentum problem? [PDF]

open access: yes, 2004
The hot star wind momentum problem η = Mν∞/(L/c)» much greater than 1 is revisited, and it is shown that the conventional belief, that it can be solved by a combination of clumping of the wind and multiple scattering of photons, is ...
Li, Q.   +13 more
core   +1 more source

A study of U Aquarii and the nucleosynthesis of neutrons and S-process elements in evolved stars of low mass [PDF]

open access: yes, 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

Evolution of Wolf-Rayet stars as black hole progenitors [PDF]

open access: yes, 2021
Evolved Wolf-Rayet stars form a key aspect of massive star evolution, and their strong outflows determine their final fates. In this study, we calculate grids of stellar models for a wide range of initial masses at five metallicities (ranging from solar ...
Vink, J S   +3 more
core   +1 more source

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