Zobrazeno 1 - 10
of 217
pro vyhledávání: '"Wolter, U."'
Autor:
Uttenthaler, S., Shetye, S., Nanni, A., Aringer, B., Eriksson, K., McDonald, I., Gobrecht, D., Höfner, S., Wolter, U., Cristallo, S., Bernhard, K.
Context: The details of the mass-loss process in the late stages of low- and intermediate-mass stellar evolution are not well understood, in particular its dependence on stellar parameters. Mira variables are highly suitable targets for studying this
Externí odkaz:
http://arxiv.org/abs/2409.19604
Autor:
Cao, Dongtao, Gu, Shenghong, Ge, Jian, Wang, Tinggui, Zhou, Jilin, Chang, Liang, Wolter, U., Mittag, M., Schmitt, J. H. M. M., Perdelwitz, V.
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 482, Issue 1, p.988-998, January 2019
We present the results of time-resolved high-resolution spectroscopic observations of the very active RS Canum Venaticorum (RS CVn) star SZ Piscium (SZ Psc), obtained during two consecutive observing nights on October 24 and 25, 2011. Several optical
Externí odkaz:
http://arxiv.org/abs/2401.02590
Autor:
Cao, Dongtao, Gu, Shenghong, Wolter, U., Mittag, M., Schmitt, J. H. M. M., Gao, Dongyang, Hu, Shaoming
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 523, Issue 3, pp.4146-4157, August 2023
We present a study of high-resolution spectra of RS Canum Venaticorum (RS CVn), a prototype of active binary systems. Our data were obtained from 1998 to 2017 using different telescopes. We analyze the chromospheric activity indicators Ca II IRT, H$_
Externí odkaz:
http://arxiv.org/abs/2401.02583
Autor:
Zamanov, R. K., Stoyanov, K. A., Marchev, D., Tomov, N. A., Wolter, U., Bode, M. F., Nikolov, Y. M., Stefanov, S. Y., Kurtenkov, A., Latev, G. Y.
We present new spectroscopic observations of the Be/black hole binary MWC 656 obtained during the period 2015 - 2021. We measure the equivalent width of H$\alpha$ (EW$_\alpha$), H$\beta$ ($EW_\beta$), and the distance between the peaks of H$\alpha$ (
Externí odkaz:
http://arxiv.org/abs/2206.06013
Autor:
Jeffers, S. V., Cameron, R. H., Marsden, S. C., Saikia, S. Boro, Folsom, C. P., Jardine, M. M., Morin, J., Petit, P., See, V., Vidotto, A. A., Wolter, U., Mittag, M.
Cool main-sequence stars, such as the Sun, have magnetic fields which are generated by an internal dynamo mechanism. In the Sun, the dynamo mechanism produces a balance between the amounts of magnetic flux generated and lost over the Sun's 11-year ac
Externí odkaz:
http://arxiv.org/abs/2201.07530
Autor:
Coffaro, M., Stelzer, B., Orlando, S., Hall, J., Metcalfe, T. S., Wolter, U., Mittag, M., Sanz-Forcada, J., Schneider, P. C., Ducci, L.
Publikováno v:
A&A 636, A49 (2020)
In 2015 we started the XMM-Newton monitoring of the young solar-like star Epsilon Eridani (440 Myr), one of the youngest solar-like stars with a known chromospheric CaII cycle. By analyzing the most recent Mount Wilson S-index CaII data of this star,
Externí odkaz:
http://arxiv.org/abs/2002.11009
Autor:
Xiang, Yue, Gu, Shenghong, Wolter, U., Schmitt, J. H. M. M., Cameron, A. Collier, Barnes, J. R., Mittag, M., Perdelwitz, V., Kohl, S.
We present the first Doppler images of the prototypical active binary star RS CVn, derived from high-resolution spectra observed in 2004, 2016 and 2017, using three different telescopes and observing sites. We apply the least-squares deconvolution te
Externí odkaz:
http://arxiv.org/abs/2001.02572
Autor:
Zamanov, R. K., Stoyanov, K. A., Wolter, U., Marchev, D., Tomov, N. A., Bode, M. F., Nikolov, Y. M., Marchev, V., Iliev, L., Stateva, I. K.
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period December 2017 - January 2020 (MJD~58095 - MJD~58865). In December 2017 the $H\alpha$, $H\beta$, and HeI 6678 emission lines were symmetric with violet-to-re
Externí odkaz:
http://arxiv.org/abs/1906.11587
We report photometric observations in Johnson UBV bands of the short term variability of Mira. The amplitude detected is 0.16 mag in B band. Adopting interstellar extinction E(B-V)=0, we find for the flickering source colour B-V=1.3, temperature T=37
Externí odkaz:
http://arxiv.org/abs/1903.03782
Publikováno v:
A&A 622, A173 (2019)
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999 - 2018. Using new and published data, we found that during "disc-rise" the expansion velocity of the circumstellar disc is 0.4 - 0.7 km/s. Our results
Externí odkaz:
http://arxiv.org/abs/1811.09162