Zobrazeno 1 - 10
of 84
pro vyhledávání: '"Todt, Helge"'
Spectroscopic observations have shown for decades that the Wolf-Rayet (WR) phenomenon is ubiquitous among stars with different initial masses. Although much effort to understand the winds from massive WR stars has been presented in the literature, no
Externí odkaz:
http://arxiv.org/abs/2405.10177
Publikováno v:
A&A 686, A29 (2024)
We present spectroscopy of three hydrogen-deficient central stars of faint planetary nebulae, with effective temperatures ($T_\mathrm{eff}$) in excess of 100,000 K. The nucleus of RaMul 2 is a Population II Wolf-Rayet star of spectral type [WC], and
Externí odkaz:
http://arxiv.org/abs/2402.18976
Autor:
Marques, Bárbara L. Miranda, Monteiro, Hektor, Aleman, Isabel, Akras, Stavros, Todt, Helge, Corradi, Romano L. M.
The study of planetary nebulae provides important constraints for many aspects of stellar and Galactic evolution. Hen 2-108 is a poorly known planetary nebula with a slight elliptical morphology and a peculiar central star (CS), which has defied clas
Externí odkaz:
http://arxiv.org/abs/2306.03201
Autor:
Lefever, Roel R., Sander, Andreas A. C., Shenar, Tomer, Poniatowski, Luka G., Dsilva, Karan, Todt, Helge
Given their strong stellar winds, Wolf-Rayet (WR) stars exhibit emission line spectra that are predominantly formed in expanding atmospheric layers. The description of the wind velocity field $v(r)$ is therefore a crucial ingredient in the spectral a
Externí odkaz:
http://arxiv.org/abs/2302.13964
Investigating the impact of different velocity fields on the spectral appearance of Wolf-Rayet stars
Autor:
Lefever, Roel R., Shenar, Tomer, Sander, Andreas A. C., Poniatowski, Luka, Dsilva, Karan, Todt, Helge
The emission line spectra of WR stars are often formed completely in the optically thick stellar wind. Hence, any assumption on the wind velocity law in a spectral analysis has a profound impact on the determination of the stellar parameters. By comp
Externí odkaz:
http://arxiv.org/abs/2209.06043
While there is strong evidence for clumping in the winds of massive hot stars, very little is known about clumping in the winds from Central Stars. We have checked [WC]-type CSPN winds for clumping by inspecting the electron-scattering line wings. At
Externí odkaz:
http://opus.kobv.de/ubp/volltexte/2008/1771/
Autor:
Sander, Andreas A. C., Vink, Jorick S., Higgins, Erin R., Shenar, Tomer, Hamann, Wolf-Rainer, Todt, Helge
Classical Wolf-Rayet (WR) stars mark an important stage in the late evolution of massive stars. As hydrogen-poor massive stars, these objects have lost their outer layers, while still losing further mass through strong winds indicated by their promin
Externí odkaz:
http://arxiv.org/abs/2202.04671
Autor:
Hajduk, Marcin, Todt, Helge, Hamann, Wolf-Rainer, Borek, Karolina, van Hoof, Peter A. M., Zijlstra, Albert A.
Publikováno v:
2020, Volume 498, pp. 1205-1220
SwSt 1 (PN G001.5-06.7) is a bright and compact planetary nebula containing a late [WC]-type central star. Previous studies suggested that the nebular and stellar lines are slowly changing with time. We studied new and archival optical and ultraviole
Externí odkaz:
http://arxiv.org/abs/2009.14616
The merger of two white dwarfs (WD) is a natural outcome from the evolution of many binary stars. Recently, a WD merger product, IRAS 00500+6713, was identified. IRAS 00500+6713 consists of a central star embedded in a circular nebula. The analysis o
Externí odkaz:
http://arxiv.org/abs/2008.10612
Autor:
Zhang, Wei, Todt, Helge, Wu, Hong, Shi, Jianrong, Hsia, Chih-Hao, Wu, Yuzhong, Wu, Chaojian, Zhao, Yongheng, Zhang, Tianmeng, Hou, Yonghui
We report the discovery of a new transition type Wolf-Rayet (WR) WN/C star in the Galaxy. According to its coordinates (R.A., Dec)J2000 = 18h51m39.7s, -05d34m51.1s, and the distance (7.11 kpc away from Earth) inferred from the second Gaia, data relea
Externí odkaz:
http://arxiv.org/abs/2008.08205