Astronomical Institute
Topic
Outburst of the symbiotic star BF Cyg with flares and collimated mass ejections
PhD. program
Astronomy and Astrophysics
Name of the supervisor
Mgr. Emil Kundra, PhD.
Contact:
Receiving school
Faculty of Mathematics, Physics and Informatics
Annotation
Consultant: RNDr. Augustin Skopal, DrSc.
Affiliation: Astronomical Insititute of Slovak Academy of Sciences, Tatranská Lomnica, 059 60 Vysoké Tatry
Syllabus:
Focus of the research: Symbiotic stars are interacting binaries with very long orbital periods (on the order of years). They consist of a red giant that is losing some of its mass and a white dwarf that is accreting it. Occasionally, on a time scale of tens of years, outbursts occur, during which we observe an increase in the brightness of the system by 2 to 7 magnitudes and significant changes in the spectrum. An outburst is often characterized by a single brightening followed by a decrease to the original brightness. In some cases, the main maximum is accompanied by a secondary flare. In the case of the symbiotic star BF Cyg, the primary outburst occurred in 2006, but the slow decline was interrupted by further flares in 2015 and 2017, after which collimated mass ejections were indicated. The high level of BF Cyg activity continues to the present. The fundamental problem is to clarify the source of energy and the mechanism that maintains such a long-lasting outburst. The essence of symbiotic star outbursts is one of the key problems of their research.
Objectives: The aim of the PhD thesis is to determine the basic physical parameters of the BF Cyg radiation regions (temperatures, radii, luminosities, emission volume, mass-loss rate from the system) during outburst that occurred in 2006, especially during flares in 2015 and 2017. This goal will be achieved by modeling the energy distribution in the BF Cyg spectrum (software available), which will distinguish its individual radiation components. Furthermore, it is the determination of the basic physical parameters of collimated mass ejections and their evolution in different stages of the outburst. Both tasks should contribute to a better understanding of the process of mass accretion onto a white dwarf as well as the mechanism that maintains the high energy output of BF Cyg for a long time (17 years so far). The doctoral student will work with existing observations (UBVRI photometry, spectroscopy) with the possibility of obtaining new observations with the AISAS telescopes.
Requirements: knowledge of English, basics of programming
Research field: Symbiotic stars and novae
For a next information go to:
https://www.astro.sk/en/study/phd-study/
Affiliation: Astronomical Insititute of Slovak Academy of Sciences, Tatranská Lomnica, 059 60 Vysoké Tatry
Syllabus:
Focus of the research: Symbiotic stars are interacting binaries with very long orbital periods (on the order of years). They consist of a red giant that is losing some of its mass and a white dwarf that is accreting it. Occasionally, on a time scale of tens of years, outbursts occur, during which we observe an increase in the brightness of the system by 2 to 7 magnitudes and significant changes in the spectrum. An outburst is often characterized by a single brightening followed by a decrease to the original brightness. In some cases, the main maximum is accompanied by a secondary flare. In the case of the symbiotic star BF Cyg, the primary outburst occurred in 2006, but the slow decline was interrupted by further flares in 2015 and 2017, after which collimated mass ejections were indicated. The high level of BF Cyg activity continues to the present. The fundamental problem is to clarify the source of energy and the mechanism that maintains such a long-lasting outburst. The essence of symbiotic star outbursts is one of the key problems of their research.
Objectives: The aim of the PhD thesis is to determine the basic physical parameters of the BF Cyg radiation regions (temperatures, radii, luminosities, emission volume, mass-loss rate from the system) during outburst that occurred in 2006, especially during flares in 2015 and 2017. This goal will be achieved by modeling the energy distribution in the BF Cyg spectrum (software available), which will distinguish its individual radiation components. Furthermore, it is the determination of the basic physical parameters of collimated mass ejections and their evolution in different stages of the outburst. Both tasks should contribute to a better understanding of the process of mass accretion onto a white dwarf as well as the mechanism that maintains the high energy output of BF Cyg for a long time (17 years so far). The doctoral student will work with existing observations (UBVRI photometry, spectroscopy) with the possibility of obtaining new observations with the AISAS telescopes.
Requirements: knowledge of English, basics of programming
Research field: Symbiotic stars and novae
For a next information go to:
https://www.astro.sk/en/study/phd-study/