Properties and nature of Be stars

Nemravová, J.; Harmanec, P.; Koubský, P.; Мирошниченко, А. С.; Yang, S.; Šlechta, M.; Buil, C.; Korčáková, D.; Votruba, V.

doi:10.1051/0004-6361/201117922

Cited by 60 publications

(91 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The series of spectroscopic observations that has previously been used by Nemravová et al (2013) was complemented with more recent ones secured at Ondřejov and La Silla: they were made with the echelle spectrograph FEROS (Kaufer et al 1999), and at Cerro Armazones with the BESO spectrograph (Steiner et al 2008;Fuhrmann et al 2011). Four archival ELODIE echelle spectra were also used (Moultaka et al 2004).…”

Section: Spectral Observationsmentioning

confidence: 99%

“…Four archival ELODIE echelle spectra were also used (Moultaka et al 2004). With this rich collection of electronic spectra, we no longer needed the early RVs from the David Dunlap Observatory (DDO) photographic spectra that were used by Nemravová et al (2013). The spectra were primarily used to obtain RV measurements of all three components of the close triple subsystem.…”

Section: Spectral Observationsmentioning

confidence: 99%

“…The photometry that has previously been used by Nemravová et al (2013) was complemented by very accurate observations acquired almost continuously over two weeks with the MOST satellite (Walker et al 2003) and by another series of Johnson UBV observations from Hvar. Additionally, we analysed the photometric minima published by Zasche et al (2014).…”

Section: Photometric Observationsmentioning

confidence: 99%

“…Initial RVs for the searching program were computed from the orbital solution presented in Nemravová et al (2013), and we searched for the RV for each component in the interval [−70; 70] km s −1 that surrounds the initial estimate. The components of the eclipsing binary Aa and Ab are very similar, therefore we had to verify that the two components had not been interchanged by the program, especially near the conjunctions.…”

Section: Rvs Measured By Comparing the Observed And Synthetic Line Prmentioning

confidence: 99%

“…Hummel et al (2013) reported a solution of the 145.2 d orbit based on interferometric observations. The first detailed, but still preliminary study of ξ Tau was published by Nemravová et al (2013). These authors analysed numerous spectral, photometric and interferometric observations and discovered the apsidal motion of the 145.2 d orbit with a period 224 ± 147 yr.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

ξTauri: a unique laboratory to study the dynamic interaction in a compact hierarchical quadruple system

Nemravová

Harmanec

Brož

et al. 2016

A&A

Self Cite

View full text Add to dashboard Cite

Context. Compact hierarchical systems are important because the effects caused by the dynamical interaction among its members occur on a human timescale. These interactions play a role in the formation of close binaries through Kozai cycles with tides. One such system is ξ Tauri: it has three hierarchical orbits: 7.14 d (eclipsing components Aa, Ab), 145 d (components Aa+Ab, B), and 51 yr (components Aa+Ab+B, C). Aims. We aim to obtain physical properties of the system and to study the dynamical interaction between its components. Methods. Our analysis is based on a large series of spectroscopic photometric (including space-borne) observations and long-baseline optical and infrared spectro-interferometric observations. We used two approaches to infer the system properties: a set of observation-specific models, where all components have elliptical trajectories, and an N-body model, which computes the trajectory of each component by integrating Newton's equations of motion. Results. The triple subsystem exhibits clear signs of dynamical interaction. The most pronounced are the advance of the apsidal line and eclipsetiming variations. We determined the geometry of all three orbits using both observation-specific and N-body models. The latter correctly accounted for observed effects of the dynamical interaction, predicted cyclic variations of orbital inclinations, and determined the sense of motion of all orbits. Using perturbation theory, we demonstrate that prominent secular and periodic dynamical effects are explainable with a quadrupole interaction. We constrained the basic properties of all components, especially of members of the inner triple subsystem and detected rapid low-amplitude light variations that we attribute to co-rotating surface structures of component B. We also estimated the radius of component B. Properties of component C remain uncertain because of its low relative luminosity. We provide an independent estimate of the distance to the system. Conclusions. The accuracy and consistency of our results make ξ Tau an excellent test bed for models of formation and evolution of hierarchical systems.

show abstract