Results 61 to 70 of about 11,425 (209)

Red and Yellow Hypergiants

Galaxies
The red and yellow hypergiants are a rare and important phase in the evolution of the most massive stars that can reach the cool part of the HR Diagram.
Terry Jones
doaj   +1 more source

Beyond Accretion Limits: The Rise of Pulsating Gems

Astronomische Nachrichten, Volume 346, Issue 1, January 2025.
ABSTRACT The discovery of several ultraluminous X‐ray sources exhibiting fast and rapidly evolving X‐ray pulsations unequivocally associates these sources with accreting neutron stars orbiting relatively massive companion stars (> 8M ⊙$$ {}_{\odot } $$).
Gian Luca Israel, Roberta Amato, Matteo Imbrogno, Nicoló Oreste Pinciroli Vago, on behalf of a Larger Team, Guillermo Andres Rodríguez Castillo, Andrea Belfiore, Luigi Stella, Matteo Bachetti, Felix Fürst, Dom Walton, Matthew Middleton, Murray Brightman, Fabio Pintore, Ciro Pinto, Silvia Conforti, Luca Zampieri, Chiara Salvaggio, Anna Wolter, Andrea Tiengo, Andrea De Luca, Paolo Esposito, Ruben Salvaterra, Hannah Earnshaw, Tim Roberts, Andres Gúrpide, Sara Motta   +26 more
wiley   +1 more source

Physical Environment of Accreting Neutron Stars

Advances in Astronomy, Volume 2016, Issue 1, 2016., 2016
Neutron stars (NSs) powered by accretion, which are known as accretion‐powered NSs, always are located in binary systems and manifest themselves as X‐ray sources. Physical processes taking place during the accretion of material from their companions form a challenging and appealing topic, because of the strong magnetic field of NSs.
J. Wang, Elmetwally Elabbasy
wiley   +1 more source

Visual Orbits of Wolf–Rayet Stars. II. The Orbit of the Nitrogen-rich Wolf–Rayet Binary WR 138 Measured with the CHARA Array

The Astrophysical Journal
Classical Wolf–Rayet (WR) stars are descendants of massive OB-type stars that have lost their hydrogen-rich envelopes and are in the final stages of stellar evolution, possibly exploding as Type Ib/c supernovae.
Amanda Holdsworth, Noel Richardson, Gail H. Schaefer, Jan J. Eldridge, Grant M. Hill, Becca Spejcher, Jonathan Mackey, Anthony F. J. Moffat, Felipe Navarete, John D. Monnier, Stefan Kraus, Jean-Baptiste Le Bouquin, Narsireddy Anugu, Sorabh Chhabra, Isabelle Codron, Jacob Ennis, Tyler Gardner, Mayra Gutierrez, Noura Ibrahim, Aaron Labdon, Cyprien Lanthermann, Benjamin R. Setterholm   +21 more
doaj   +1 more source

A Study of Primordial Very Massive Star Evolution

The Astrophysical Journal, 2023
We present new evolutionary models of primordial very massive stars with initial masses ranging from 100 to 1000 M _⊙ that extend from the main sequence to the onset of dynamical instability caused by the creation of electron–positron pairs during core C,
Guglielmo Volpato, Paola Marigo, Guglielmo Costa, Alessandro Bressan, Michele Trabucchi, Léo Girardi   +5 more
doaj   +1 more source

Evolution and the period-luminosity relation for red supergiants in the Magellanic Clouds [PDF]

, 2013
Excitation of radial pulsations in red supergiants of Magellanic Clouds is investigated using the stellar evolution calculations and the self-consistent solution of the equations of radiation hydrodynamics and turbulent convection. The stars with initial
Fadeyev, Yuri A.
core   +1 more source

P Cygni Stars as an Intermediate Stage Between Red Supergiants and Wolf-Rayet Stars [PDF]

Symposium - International Astronomical Union, 1984
P Cygni's evolutionary status is evaluated using its recently redetermined basic parameters (Lamers et al. 1983) to plot the star on the HRD (Figure 1). The theoretical evolutionary track of a 60 M⊙ star passes through P Cygni's error box twice. From a comparison of the time scales along the two parts of the track it is found to be twenty times more ...
Henny J.G.L.M. Lamers, Mart de Groot, Angelo Cassatella   +2 more
openaire   +1 more source

Micritisation products in the inner ramp settings of the Abu Dhabi Lagoon

The Depositional Record, Volume 10, Issue 4, Page 402-425, September 2024.
Journey inside carbonate grains; internal microstructures of micritic envelopes and peloids in the Abu Dhabi lagoon. Abstract In numerous carbonate reservoirs in the Middle East, peloidal packstone‐grainstones are rock types with excellent pore storage potential in micritised microporous grains.
Thomas Teillet, Mohamed Harkat, Kai Hachmann, Elisa Garuglieri, Viswasanthi Chandra, Daniele Daffonchio, Mónica Sánchez‐Román, Volker Vahrenkamp   +7 more
wiley   +1 more source

Photospheric Helium Abundance in Cool Giants: A Comprehensive Study

The Astrophysical Journal
High-resolution optical spectra of 16 red giants, two early asymptotic giant branch (AGB) stars, and two supergiants, having no/minimal - to super-lithium (Li)-rich abundances, are analyzed to investigate the helium (He)-enhancement. The spectra of eight
B. P. Hema, Gajendra Pandey
doaj   +1 more source

The impact of mass-loss on the evolution and pre-supernova properties of red supergiants [PDF]

, 2014
The post main-sequence evolution of massive stars is very sensitive to many parameters of the stellar models. Key parameters are the mixing processes, the metallicity, the mass-loss rate and the effect of a close companion.
Chomienne, V., Eggenberger, P., Ekström, S., Georgy, C., Granada, A., Groh, J., Levesque, E., Maeder, A., Massey, P., Meynet, G.   +9 more
core   +2 more sources