Results 61 to 70 of about 3,144 (170)

Analysis of far-infrared fine-structure emissions from the red supergiant µ Cephei

Astronomy & Astrophysics
Context. The complex structure and dynamics of red supergiant stars (RSGs) and their variability hinder the spectral analysis of the conditions above their photosphere.
Wiesemeyer H., Marinho L., Harper G. M., Baudry A., Herpin F., Ricken O.   +5 more
doaj   +1 more source

Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger   +9 more
wiley   +1 more source

Iron line diagnostics of the stellar wind in X1908+075

Astronomy & Astrophysics
Aims. X1908+075 is a supergiant X-ray binary (SgXB) system formed by an evolved OB star and a neutron star (NS) orbiting it with a 4.4-day period. In this study, we aim to characterize the stellar wind properties, constrain the system geometry, and ...
Planelles-Villalva J., Torrejón J. M., Rodes-Roca J. J., Sanjurjo-Ferrín G.   +3 more
doaj   +1 more source

Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic O9.7 V star HD 54879 using rotational modulation of the Hα profile

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract The magnetic field in the O9.7 V star HD 54879 has been monitored for almost a decade. Spectropolarimetric observations reveal a rather strong mean longitudinal magnetic field that varies with a period of about 7.41 years. Observations in the Hα$$ \alpha $$ line show a variation with the same period, while the Hβ$$ \beta $$ line shows only ...
Manfred Küker, S. P. Järvinen, S. Hubrig, Ilya Ilyin, M. Schöller   +4 more
wiley   +1 more source

Turbulent Structure in the Upper Chromospheres of Cool Supergiants

, 2013
Although the contribution of a chromosphere to the total flux may be small, it plays a vital role as the interface between the star and interstellar space, as it is where the stellar wind originates.
R.E. Griffin
core   +1 more source

Red supergiants around the obscured open cluster Stephenson 2 [PDF]

, 2012
Context. Several clusters of red supergiants have been discovered in a small region of the Milky Way close to the base of the Scutum-Crux Arm and the tip of the Long Bar.
Jiménez Esteban, Francisco M., Jiménez-Esteban, F., González-Fernandez, C., F. Jiménez-Esteban, Marco, Amparo, Marco, A., M. Garcia, González-Fernández, Carlos, A. Marco, Negueruela, Ignacio, Clark, J. S., Clark, J. Simon, E. Solano, Garcia, M., García, Miriam, J. S. Clark, Solano, E., I. Negueruela, Negueruela, I., C. González-Fernández, Solano, Enrique   +20 more
core   +1 more source

The Complex Upper HR Diagram—Redux: The Low-Metallicity Galaxies

Universe
The properties of luminous evolved stars in nearby resolved galaxies are briefly reviewed with emphasis on recent results for the low-metallicity dwarf irregulars.
Roberta M. Humphreys
doaj   +1 more source

MODELS OF CIRCUMSTELLAR MASERS IN BIPOLAR OUTFLOWS

Odessa Astronomical Publications, 2017
Sources of molecular maser radio emission in envelopes of late-type variable stars (red giants and supergiants) are considered. Radio and optical data on asymmetry of mass loss process in red giants are briefly reviewed.
G. M. Rudnitskij
doaj   +1 more source

Understanding A-type supergiants

, 1999
This paper is the first of a series whose aim is to perform a systematic study of A-type supergiant atmospheres and winds. Here we present a spectral atlas of 41 A-supergiants observed by us in high and medium resolution in the visible and ultraviolet ...
E. Verdugo, A.I. Gómez de Castro, A. Talavera   +2 more
core   +1 more source

The origin of dispersion in the wind mass-loss rate–luminosity relation of massive O stars

Astronomy & Astrophysics
Context. Stellar winds of hot stars are accelerated by the radiative force that mainly comes from the line transitions of heavy elements. As a result, the wind mass-loss rate is expected to scale mostly with the stellar luminosity.
Krtička J., Krtičková I.
doaj   +1 more source