Search Publications
The symbiotic recurrent nova V3890 Sgr: binary parameters and pre-outburst activity
Udalski, A.; Mikołajewska, J.; Iłkiewicz, K. +4 more
We present and analyse optical photometry and high-resolution Southern African Large Telescope spectra of the symbiotic recurrent nova V3890 Sgr at quiescence. The orbital period, P = 747.6 d, has been derived from both photometric and spectroscopic data. Our double-line spectroscopic orbits indicate that the mass ratio is q = Mg/M…
High-resolution spectroscopy of the hot Am star HR 3383
Nielsen, K. E.; Leckrone, D. S.; Wahlgren, G. M.
We present the spectrum analysis of the hot Am star HR 3383 (A1 Vm). Hubble Space Telescope STIS and Nordic Optical Telescope SOFIN data are modelled with synthetic spectra, and abundances are investigated for 78 elements. Most light elements up through oxygen show deficiencies, compared to solar abundances, followed by the general trend of increa…
Outbursts and stellar properties of the classical Be star HD 6226
Gies, Douglas R.; Wang, Luqian; Richardson, Noel D. +58 more
The bright and understudied classical Be star HD 6226 has exhibited multiple outbursts in the last several years during which the star grew a viscous decretion disc. We analyse 659 optical spectra of the system collected from 2017 to 2020, along with a ultraviolet spectrum from the Hubble Space Telescope and high cadence photometry from both Trans…
Confirmation of ξ1 CMa's ultra-slow rotation: magnetic polarity reversal and a dramatic change in magnetospheric UV emission lines
Wade, G. A.; Fullerton, A. W.; Shultz, M. E. +5 more
The magnetic β Cep pulsator ξ1 CMa has the longest rotational period of any known magnetic B-type star. It is also the only magnetic B-type star with magnetospheric emission that is known to be modulated by both rotation and pulsation. We report here the first unambiguous detection of a negative longitudinal magnetic field in ξ1
A celestial matryoshka: dynamical and spectroscopic analysis of the Albireo system
Drimmel, Ronald; Bastian, Ulrich; Sozzetti, Alessandro +4 more
We present a spectroscopic characterization and a new orbital solution for the binary system β Cyg Aa/Ac (MCA 55), the primary component ( β Cyg A) of the well-known wide double star Albireo. By matching evolutionary tracks to the physical parameters of all three Albireo stars ( β Cyg Aa, Ac, and B) as obtained from a spectroscopic analysis of TIG…
Space observations of AA Doradus provide consistent mass determinations. New HW-Vir systems observed with TESS
Heber, U.; Irrgang, A.; Reed, M. D. +5 more
We present an overview of eclipsing systems of the HW-Virginis (HW-Vir) type, based on space observations from the Transiting Exoplanet Survey Satellite (TESS) mission. We perform a detailed analysis of the properties of AA Doradus (AA Dor), which was monitored for almost a full year. This excellent time series data set permitted us to search for …
Discovery of new mercury-manganese stars, including a fast rotator
Nuñez, N. E.; González, J. F.; Veramendi, M. E. +3 more
The origin of mercury-manganese (HgMn) stars is still poorly understood and the statistical analysis of an extensive sample of well characterized objects would be very valuable. Nevertheless, the compilation of a clean and reliable list of all known HgMn stars, and complete characterization of those objects, is still a pending issue. We report the…
UV spectroscopy confirms SU Lyn to be a symbiotic star
Joshi, Vishal; Kumar, Vipin; Srivastava, Mudit K. +1 more
SU Lyn, a star that ostensibly appears to be an unremarkable late M type giant, has recently been proposed to be a symbiotic star largely based on its hard X-ray properties. The star does not display, in low-resolution optical spectra, the high excitation lines typically seen in the spectra of symbiotic stars. In this work, ultraviolet (UV), optic…