Results 81 to 90 of about 12,394 (217)

Extending the cosmic distance ladder two orders of magnitude with strongly lensed Cepheids, carbon AGB stars, and RGB stars

Astronomy & Astrophysics
Gravitational lensing by galaxy clusters can create extreme magnification (μ > 1000) near the cluster caustics, thereby enabling detections of individual luminous stars in high-redshift background galaxies.
Diego J. M., Willner S. P., Palencia J. M., Windhorst R. A.   +3 more
doaj   +1 more source

Quantitative Spectroscopy of Supergiants [PDF]

Publications of the Astronomical Society of the Pacific, 2003
Blue supergiants of spectral types B and A are the visually brightest stars in spiral and irregular galaxies, with their most luminous members (at M_V=-10) outshining entire dwarf galaxies. This characteristic allows us to use them as probes to study the Local Universe in great detail.
openaire   +2 more sources

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

The winds of OBA hypergiants and luminous blue variables

Astronomy & Astrophysics
Context. OBA hypergiants are evolved massive stars with notable wind features in their optical spectrum. Located at the cool end of the line-driven wind regime, many of these objects are candidate luminous blue variables (LBVs) and presumably close to ...
Bernini-Peron M., Sander A. A. C., Sabhahit G. N., Najarro F., Ramachandran V., Vink J. S.   +5 more
doaj   +1 more source

THE NATURE OF THE TYPE C SEMI-REGULAR VARIABLES

Odessa Astronomical Publications, 2017
The type C semi-regular (SRC) variables are M-type supergiants like Betelgeuse that undergo regular periodic brightness fluctuations superposed upon seemingly irregular trends.
D. G. Turner
doaj   +1 more source

The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants

, 2008
The quantitative analysis of low resolution spectra of A and B supergiants is used to determine a distance modulus of 24.99 +/- 0.10 mag (995 +/- 46 Kpc) to the Local Group galaxy WLM.
Appenzeller I., Deeming T. J., Fabio Bresolin, Ferraro F. R., Gieren W., Grzegorz Pietrzyński, Miguel A. Urbaneja, Norbert Przybilla, Rolf‐Peter Kudritzki, Whitney C. A., Wolfgang Gieren   +10 more
core   +1 more source

Infrared Photometry of Red Supergiants in Young Clusters in the Magellanic Clouds [PDF]

, 1999
We present broad-band infrared photometry for 52 late-type supergiants in the young Magellanic Clouds clusters NGC 330, NGC 1818, NGC 2004 and NGC 2100. Standard models are seen to differ in the temperature they predict for the red supergiant population ...
Barbuy B., Bessell M. S., Bessell M. S., Bohm-Vitense E., Caloi V., Caloi V., Carter B. S., Charbonnel C., Chiosi C., Fagotto F., Hill V., Jones T. J., McGregor P. J., Meliani M. T., Oliva E., Robertson J., Salaris M., Schaerer D., Spite F., Stefan C. Keller, Walker M. F.   +20 more
core   +2 more sources

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

Evaluating Gaia Astrometric Quality and Distances for Galactic Hot Supergiants

Universe
Distances to Galactic BA supergiants are essential for determining their luminosities, radii, and positions on the Hertzsprung–Russell diagram, yet Gaia parallaxes for these bright, extended sources are often affected by systematics.
Nadezhda L. Vaidman, Shakhida T. Nurmakhametova, Aziza B. Umirova, Serik A. Khokhlov, Aldiyar T. Agishev, Berik S. Yermekbayev   +5 more
doaj   +1 more source

Spectroscopic and physical parameters of Galactic O-type stars. II. Observational constraints on projected rotational and extra broadening velocities as a function of fundamental parameters and stellar evolution

, 2013
Rotation is of key importance for the evolution of hot massive stars, however, the rotational velocities of these stars are difficult to determine. Based on our own data for 31 Galactic O stars and incorporating similar data for 86 OB supergiants from ...
Herrero, A., Langer, N., Markov, H., Markova, N., Puls, J., Simón-Díaz, S.   +5 more
core   +1 more source