Marek Chrastina

Transient Jets in the Symbiotic Prototype Z Andromedae

We present the development of collimated bipolar jets from the symbiotic prototype Z And that appeared and disappeared during its 2006 outburst. We monitored the outburst with optical high-resolution spectroscopy and multicolor UBVR C photometry. In 2006 July, Z And reached its historical maximum at U ~ 8.0. After ~1 mag decline in mid-August, it kept its brightness at a high level of U ~ 9 up to 2007 January. During this period, rapid photometric variations with ?m ~ 0.06 mag on the timescale of hours developed. Simultaneously, high-velocity satellite components appeared on both sides of the H? and H? emission line profiles. Their presence was transient, being detected to the end of 2006. They were launched asymmetrically with a red/blue velocity ratio of 1.2-1.3. From about mid-August onward they became symmetric at ~?1200 km s?1, reducing the velocity to ~?1100 km s?1 at their disappearance. The spectral properties of these satellite emissions indicated the ejection of bipolar jets collimated within an average opening angle of 61. If the jets were expelled at the escape velocity, then the mass of the accreting white dwarf is M WD ~ 0.64 M ?. We estimated the average outflow rate via jets to M ? yr?1, during their August-September maximum, which corresponds to the emitting mass in jets, M em jet ~ 6 ? 10?10(R jet/1 AU)3/2 M ?. During their lifetime, the jets released a total mass of M total jet 7.4 ? 10?7 M ?. Evolution in the rapid photometric variability and asymmetric ejection of jets around the optical maximum can be explained by a disruption of the inner parts of the disk caused by radiation-induced warping of the disk.

New analysis of the light time effect in TU Ursae Majoris

We investigate in detail the LiTE of the most probable binary candidate TU UMa. We used a new code applied on previously available and newly determined maxima timings to confirm binarity and refine parameters of the orbit of the RRab component in the binary system. The binary hypothesis is also tested using RV measurements. We used new approach to determine brightness maxima timings based on template fitting. This can also be used on sparse or scattered data. This approach was successfully applied on measurements from different sources. To determine the orbital parameters of the double star TU UMa, we developed a new code to analyse LiTE that also includes secular variation in the pulsation period. Its usability was successfully tested on CL Aur, an eclipsing binary with mass-transfer in a triple system that shows similar changes in the O-C diagram. Since orbital motion would cause systematic shifts in mean RVs (dominated by pulsations), we computed and compared our model with centre-of-mass velocities. They were determined using high-quality templates of RV curves of RRab stars. Maxima timings adopted from the GEOS database (168) together with those newly determined from sky surveys and new measurements (85) were used to construct an O-C diagram spanning almost five proposed orbital cycles. This data set is three times larger than data sets used by previous authors. Modelling of the O-C dependence resulted in 23.3-year orbital period, which translates into a minimum mass of the second component of about 0.33 M_s. Secular changes in the pulsation period of TU UMa over the whole O-C diagram were satisfactorily approximated by a parabolic trend with a rate of -2.2 ms/yr. To confirm binarity, we used RV measurements from nine independent sources. Although our results are convincing, additional long-term monitoring is necessary to unambiguously confirm the binarity of TU UMa.

NSVS 01031772 Cam: A New Low-Mass Triple?

We present a photometric study of the newly discovered low-mass eclipsing binary NSVS 01031772 Cam based on observations obtained at Ondřejov observatory from 2007 – 2011.

The MUNI Photometric Archive

Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University,Kotl´aˇrsk´a 2, CZ-61137 Brno, Czech Republic, homepage:http://astro.physics.muni.czAbstract.In the 1990s of the last century, CCD cameras became more reachable. Due to manyadvantages of CCD cameras, astronomers beganusing them as the primary detector for photom-etry of stellar objects. A typical observatory, which operates one telescope at a time, obtained0.5 TB of raw data during two decades, that means one million about 500 kB-sized files. Thereare several observatories in the Czech Republic and Slovakia (taking into account all scientific,public as well as private ones). A rough estimate of the total amount of this photometric data is10 TB, which could be a very interesting source of observational data. Unfortunately, these dataare not available online. These data are stored in observatory archives in arbitrary format. Oftenit is not even possible to find requested data. We have decided to change this state by establish-ing a common archive of raw photometric data, which would be available online together withtools for searching, listing etc. We already defined the data format, file and directory structureof our archive. We developed sophisticated tools for archive maintenance as well. Our goal is toprovide data storage with simple and straightforward access and we are ready to interconnectwith the VO right after the IVOA Photometry Data Model will be released.Keywords.astronomical data bases, techniques: photometric, methods: data analysis