Jaroslav Merc

Astronomical Institute of Charles University in Prague
Institute of Physics, P. J. Šafárik University in Košice

I am a PhD student at Charles University in Prague and at the same time at P. J. Šafárik University in Košice. My research focuses on symbiotic binaries.

ADS Entry: Merc, J.
Scopus ID: 57188984705
ResearcherID: C-4044-2018
ORCID: 0000-0001-6355-2468

Research Interests

Symbiotic Binaries

Symbiotic stars are strongly interacting systems, in which physical mechanisms related to transfer and accretion of matter cause observable activity. During their active stages, which may last from a few days to decades, they manifest increases of brightness (about 2–5 mag) and significant changes in their spectra. Symbiotic systems are detached binaries with orbital periods of hundreds to thousands of days.

Cataclysmic Variables

Cataclysmic variables are closely related to the group of symbiotic binaries. These stars are characterised by irregular increases of the brightness by a large factor. Usually, they are much closer systems as in the case of symbiotic binaries, but the effects connected with the mass transfer are similar. Short orbital periods, however, represent an undeniable advantage from the observer's point of view.

White Dwarfs

Hot components of symbiotic binaries are usually white dwarfs. Unlike typical white dwarfs which are final stages of single low-mass stars and are very faint, white dwarfs in symbiotic binaries are characterised by very high temperature and luminosity due to quasi-steady hydrogen burning on their surfaces. Moreover, white dwarfs in symbiotic systems may be one of the progenitors of supernovae Ia, which are used as a standard candles in astronomy.

Supernovae Ia

Type Ia supernova occurs in binary system when a white dwarf component reaches Chandrasekhar mass limit (1.44 solar masses). As the mass of white dwarfs which explode as supernovae Ia is same, they produce consistent peak luminosity. Because of that, these explosions are used as a standard candles to measure the distance to their host galaxies. Symbiotic binaries may be one of the progenitors of supernovae Ia.

Papers & Talks

Papers

2021

Merc, J., Gális, R., Velez, P., Charbonnel, S., Garde, O., Le Dû, P., Mulato, L.; Petit, T. (2021). Brightening of SS73 141: Outburst of Z And-type? The Astronomer’s Telegram, 14874, 1
Merc, J., Gális, R., Garde, O., Mulato, L., Le Dû, P., Charbonnel, S., Petit, T. (2021). Ongoing brightening of the eclipsing symbiotic star AR Pav. The Astronomer’s Telegram, 14837, 1
Merc, J., Gális, R., Wolf, M., Velez, P., Buil, C., et al. (2021). Spectroscopic and photometric analysis of symbiotic candidates - I. Ten candidates on classical symbiotic stars. Monthly Notices of the Royal Astronomical Society, 506, 4151
Mártonfi, P., Gális, R., Merc, J. (2021). Long-term photometric activity of AX Persei. Open European Journal on Variable Stars, 220, 26
Merc, J., Gális, R., Vrašťák, M., Teyssier, F., Boyd, D., Leedjärv, L., Wolf, M. (2021). Symbiotic binaries as ideal targets for amateur observers. Open European Journal on Variable Stars, 220, 11
Merc, J., Gális, R., Charbonnel, S., Garde, O., Le Dû, P., Mulato, L., Petit, T. (2021). TCP J18224935-2408280 is an outburst of a symbiotic star. The Astronomer’s Telegram, 14691, 1
Wolf, M., Kučáková, H., Zasche, P., Hornoch, K., Kára, J., Merc, J., Zejda, M. (2021). Possible substellar companions in dwarf eclipsing binaries: SDSS J143547.87+373338.5, NSVS 7826147, and NSVS 14256825. Astronomy & Astrophysics, 647, A65
Merc, J., Gális, R., Leedjärv, L., Wolf, M. (2021). Yellow symbiotic star AG Draconis in the scope of the New Online Database of Symbiotic Variables. The Golden Age of Cataclysmic Variables and Related Objects - V, Proceedings of Science, 368, 43
Merc, J., Kalup, Cs., Rathour, R. S., Sánches Arias, J. P., Beck, P. G. (2021). Asteroseismology of the heartbeat star KIC 5006817. Contributions of the Astronomical Observatory Skalnaté Pleso, 51, 45
Dubovský, P. A., Merc, J., Gális, R., Wolf, M. (2021). Spectroscopic confirmation of the active dwarf nature of 2MASS J07363415+6538548. Research Notes of the AAS, 5, 11

2020

Merc, J., Gális, R., Wolf, M. (2020). Spectroscopic analysis of selected symbiotic candidates. WDS'20 Proceedings of Contributed Papers, 45
Merc, J., Mikołajewska, J., Gromadzki, M., Gałan, C., Iłkiewicz, K., et al. (2020). Gaia18aen: First symbiotic star discovered by Gaia. Astronomy & Astrophysics, 644, A49
Merc, J., Gális, R., Kára, J., Wolf, M., Vrašťák, M. (2020). The nature of the symbiotic candidate 2MASS J07363415+6538548 in the field of NGC 2403. Monthly Notices of the Royal Astronomical Society, 499, 2116
Zasche, P., Wolf, M., Kučáková, H., Kára, J., Merc, J., Zejda, M., Skarka, M., Janík, J., Kurfürst, P. (2020). First apsidal motion and light curve analysis of 162 eccentric eclipsing binaries from LMC. Astronomy & Astrophysics, 640, A33
Merc, J., Gális, R., Wolf, M. (2020). Galactic members in the New Online Database of Symbiotic Variables. Contributions of the Astronomical Observatory Skalnaté Pleso, 50, 426

2019

Merc, J., Gális, R., Wolf, M. (2019). Symbiotic Variables in the Local Group and Beyond. WDS'19 Proceedings of Contributed Papers, 165
Cabello, C., Csörnyei, G., Merc, J., Ferreiros, V., Pessev, P. (2019). Independent Study and Spectral Classification of a Sample of Poorly Studied High Proper Motion M-dwarf Candidate Stars. Contributions of the Astronomical Observatory Skalnaté Pleso, 49, 546
Merc, J., Gális, R., Wolf, M. (2019). New Online Database of Symbiotic Variables: Symbiotics in X-rays. Astronomische Nachrichten, 340, 7, 598 (Editor’s Choice)
Merc, J., Gális, R., Wolf, M. (2019). New Online Database of Symbiotic Variables. Eruptive Stars Information Letter, 41, 78
Merc, J., Gális, R., Teyssier, F. (2019). Study of long-term spectroscopic variability of symbiotic stars based on observations of the ARAS Group. Contributions of the Astronomical Observatory Skalnaté Pleso, 49, 228
Gális, R., Merc, J., Leedjärv, L. (2019). The current active stage of the symbiotic system AG Draconis. Contributions of the Astronomical Observatory Skalnaté Pleso, 49, 197
Merc, J., Gális, R., Wolf, M., Leedjärv, L., Teyssier, F. (2019). The activity of the symbiotic binary Z Andromedae and its last outburst. Open European Journal on Variable Stars, 197, 23
Gális, R., Merc, J., Leedjärv, L., Vrašťák, M., Karpov, S. (2019). The peculiar outburst activity of the symbiotic binary AG Draconis. Open European Journal on Variable Stars, 197, 15
Merc, J., Gális, R., Teyssier, F., Boyd, D., Sims, W., Boussin, C., Campos, F. (2019). The symbiotic star AX Per is going into strong outburst. The Astronomer’s Telegram, 12660, 1
Merc, J., Gális, R., Wolf, M. (2019). First release of the New Online Database of Symbiotic Variables. Research Notes of the AAS, 3, 28

2018

Merc, J., Gális, R. (2018). CorrLAB: Correlation and Period Analysis Software. Astronomical Journal, 156, 111
Merc, J., Gális, R., Vrašťák, M., Leedjärv, L. (2018). The fourth outburst during the ongoing active stage of AG Draconis has finished. Research Notes of the AAS, 2, 142
Merc, J., Gális, R., Leedjärv, L. (2018). Recent outburst activity of the symbiotic binary AG Draconis. The Golden Age of Cataclysmic Variables and Related Objects - IV, Proceedings of Science, 315, 60
Gális, R., Merc, J., Vrašták, M., Teyssier, F., Lester, T., Boyd, D., Sims, W., Leedjärv, L. (2018). The fourth outburst during the present active stage of symbiotic binary AG Dra. The Astronomer's Telegram, 11559, 1

2017

Merc, J., Gális, R., Leedjärv, L. (2017). Recent outburst activity of the super-soft X-ray binary AG Draconis. Contributions of the Astronomical Observatory Skalnaté Pleso, 47, 192
Gális, R., Merc, J., Leedjärv, L. (2017). Outburst activity of the symbiotic binary AG Dra. Open European Journal on Variable Stars, 180, 24

2016

Merc, J., Gális, R. (2016). Korelačná analýza fotometrických a spektroskopických dát symbiotických systémov AG Dra a Z And. Prírodovedec č. 635, 197
Gális, R., Hric, L., Leedjärv, L., Merc, J. (2016). Outburst activity of the symbiotic binary AG Dra. Open European Journal on Variable Stars, 176, 22
Leedjärv, L., Gális, R., Hric, L., Merc, J., Burmeister, M. (2016). Spectroscopic view on the outburst activity of the symbiotic binary AG Draconis. Monthly Notices of the Royal Astronomical Society, 456 2558

Talks

2021

September 2021 - Merc, J., Gális, R., Wolf, M. et al. Spectroscopic and photometric analysis of symbiotic candidates: Lessons learned from the ongoing campaign (Bezovec 2021: Conference of young astronomers, Nová Lehota, Slovakia)
September 2021 - Merc, J., Mikołajewska, J., Gromadzki, M., Gałan, C., Iłkiewicz, K., et al. Gaia18aen: First symbiotic binary discovered by Gaia (Bezovec 2021: Conference of young astronomers, Nová Lehota, Slovakia)
September 2021 - Merc, J., Gális, R., Wolf, M. New Online Database of Symbiotic Variables as a tool for understanding the symbiotic population. (ChETEC MC+WG Main Meeting, Lisbon, Portugal)
September 2021 - Merc, J., Mikołajewska, J., Gromadzki, M., Gałan, C., Iłkiewicz, K., et al. Gaia18aen: First symbiotic binary discovered by Gaia (25th Conference of Slovak Physicists. Bratislava, Slovakia, held online)
May 2021 - Merc, J. Is it a symbiotic binary?! (Seminar of the Astronomical Institute of Charles University. Prague, Czech Republic, held online)
March 2021 - Merc, J., Gális, R., Wolf, M. Symbiotic binaries and where to find them. (AstroWorkshop FMFI UK, Bratislava, Slovakia, held online)
January 2021 - Merc, J., Mikołajewska, J., Gromadzki, M., Gałan, C., Iłkiewicz, K., et al. Gaia18aen: First symbiotic binary discovered by Gaia (11th OPTICON Gaia Science Alerts Workshop. Poland/United Kingdom, held online)

2020

December 2020 - Merc, J. Symbiotic binaries: The mystery of cool giants and hot dwarfs. (Seminar of Stellar Physic Department of AI ASCR. Ondřejov, Czech Republic, held online)
October 2020 - Merc, J., Gális, R., Vrašťák, M., Teyssier, F., Leedjärv, L., Wolf, M. Symbiotic binaries as ideal targets for amateur observers. (52. konference o výzkumu proměnných hvězd a exoplanet. Prague, Czech Republic, held online)
October 2020 - Merc, J. Symbiotic binaries: A story of giants and dwarfs. (Seminar of the Astronomical Institute of Charles University. Prague, Czech Republic, held online)
October 2020 - Merc, J., Gális, R. Symbiotic binaries at P. J. Šafárik University. (Bezovec 2020: Astronomical Research in Slovakia. Hlohovec, Slovakia, held online)
September 2020 - Merc, J., Gális, R., Wolf, M. Characterizing the symbiotic population using the Gaia data. (International Annual Meeting of the German Astronomical Society. Germany, held online)
September 2020 - Merc, J., Gális, R., Wolf, M. Spectroscopic analysis of selected symbiotic candidates. (Week of Doctoral Students 2020 focused on physical study branches. Prague, Czech Republic, held online)
September 2020 - Merc, J., Gális, R., Leedjärv, L. Symbiotic binaries in the scope of the ChETEC project. (ChETEC Period 4 Main Event. Split, Croatia, held online)
August 2020 - Kalup, Cs., Merc, J., Rathour, R. S., Sánches Arias, J. P., Beck, P. Asteroseismology of red giant KIC 5006817 (ERASMUS Summer School, GAIA & TESS: Tools for understanding of the Local Universe. Brno, Czech Republic, held online)

2019

September 2019 - Merc, J., Gális, R., Wolf, M. New Online Database of Symbiotic Variables. (Universe of Binaries, Binaries in the Universe, Telč, Czech Republic)
September 2019 - Merc, J., Gális, R., Leedjärv, L., Wolf, M. Yellow symbiotic star AG Draconis in the scope of the New Online Database of Symbiotic Variables. (The Golden Age of Cataclysmic Variables and Related Objects IV, Palermo, Italy)
June 2019 – Ferreiros, V., Merc, J., Csörnyei, G., Cabello, C., Pessev, P. Spectral Clasification of a Sample of Poorly Studied High Proper Motion M-dwarf Candidate Stars (ERASMUS/OPTICON Summer School, Observational Astrophysics: from proposals to publication, Stará Lesná, Slovakia)
June 2019 – Gális, R., Merc, J. The IAU100 activities in Slovakia. (European Week of Astronomy and Space Science 2019, Lyon, France)
June 2019 - Merc, J., Gális, R., Wolf, M. Symbiotic variables in the Local Group and beyond. (Week of Doctoral Students 2019 focused on physical study branches, Prague, Czech Republic)
June 2019 - Merc, J., Gális, R., Teyssier, F., Boyd, D., Leedjärv, L., Wolf, M. Spectroscopic study of (up to) four outbursts of the four symbiotic stars in the recent four years. (Conference about succeses of stellar astronomy "Bezovec 2019", Slovakia)
June 2019 - Merc, J., Gális, R., Wolf, M. New Online Database of Symbiotic Variables. (Conference about succeses of stellar astronomy "Bezovec 2019", Slovakia)
June 2019 - Gális, R.,, Merc, J., Bodnárová, R. Long-term variability of intermediate polars. (Conference about succeses of stellar astronomy "Bezovec 2019", Slovakia)
June 2019 - Gális, R.,, Merc, J. IAU: 100 years under one sky. (Conference about succeses of stellar astronomy "Bezovec 2019", Slovakia)
May 2019 - Merc, J., Gális, R., Wolf, M. New Online Database of Symbiotic Variables: Symbiotics in X-rays. (16th INTEGRAL/BART Workshop, Karlovy Vary, Czech Republic)
January 2019 - Merc, J., Gális, R., Wolf, M., Leedjärv, L. Symbiotic binaries, more than a century old puzzle. (Tříkrálová konference 2019: Setkání českých a slovenských fyziků, Prague, Czech Republic)

2018

December 2018 - Merc, J., Gális, R., Leedjärv, L. AG Draconis, a mystery older than the Republic. (Seminár Katedry teoretickej fyziky a astrofyziky PF UPJŠ, Košice, Slovakia)
December 2018 - Gális, R., Merc, J., Leedjärv, L., Vrašťák, M. The peculiar outburst activity of the symbiotic binary AG Draconis. (International meeting on variable stars research “Kolos 2018″, Slovakia)
December 2018 - Merc, J., Gális, R., Wolf, M., Leedjärv, L., Teyssier, F. The activity of the symbiotic binary Z Andromedae and its last outburst. (50. konference o výzkumu proměnných hvězd a exoplanet, Brno, Czech Republic)
December 2018 - Gális, R., Merc, J., Leedjärv, L., Vrašťák, M. The peculiar outburst activity of the symbiotic binary AG Draconis. (50. konference o výzkumu proměnných hvězd a exoplanet, Brno, Czech Republic)
November 2018 - Merc, J., Gális, R., Leedjärv, L. The activity of the symbiotic binaries AG Dra, AG Peg and Z And observed by amateur astronomers. (Astronoomia seminarid, Tartu Observatoorium, Tõravere, Estonia)
September 2018 - Merc, J., Gális, R., Teyssier, F. - Study of long-term spectroscopic variability of symbiotic stars based on observations of the ARAS Group. (Observing techniques, instrumentation and science for metre-class telescopes II, Stará Lesná, Slovakia)
September 2018 - Gális, R., Merc, J., Leedjärv, L., Vrašťák, M. - The current active stage of the symbiotic system AG Draconis. (Observing techniques, instrumentation and science for metre-class telescopes II, Stará Lesná, Slovakia)
June 2018 - Gális, R.,Merc, J., Vrašťák, M., Leedjärv, L. - The fourth outburst during the present activity of AG Draconis. (Conference about succeses of stellar astronomy "Bezovec 2018", Slovakia)

2017

October 2017 - Gális, R., Merc, J., Leedjärv, L. Súčasná aktivita symbiotickej dvojhviezdy AG Draconis. (Seminář Astronomického ústavu UK, Praha, Czech Republic)
September 2017 - Merc, J.,Gális, R., Leedjärv, L. Recent outburst activity of the symbiotic binary AG Draconis. (The Golden Age of Cataclysmic Variables and Related Objects IV, Palermo, Italy)
June 2017 - Merc, J., Gális, R. CorrLAB - Correlation and period analysis software. (Conference about successes of stellar astronomy “Bezovec 2017″, Slovakia)
June 2017 - Gális, R., Merc, J., Leedjärv, L. Recent outburst activity of AG Draconis - the story continues. (Conference about successes of stellar astronomy “Bezovec 2017″, Slovakia)
June 2017 - Leedjärv, L., Gális, R., Hric, L., Merc, J., et al. AG Draconis - a story of one active symbiotic star. (Conference about successes of stellar astronomy “Bezovec 2017″, Slovakia)
April 2017 - Merc, J., Gális, R., Leedjärv, L. Recent outburst activity of the supersoft X-ray binary AG Draconis. (14th INTEGRAL/BART Workshop, Karlovy Vary, Czech Republic)

2016

December 2016 - Gális, R., Merc, J., Leedjärv, L. Recent outburst activity of the symbiotic binary AG Draconis. (International meeting on variable stars research “Kolos 2016″, Slovakia)
November 2016 - Gális, R., Merc, J., Leedjärv, L. Súčasná aktivita symbiotickej dvojhviezdy AG Draconis. (48. konference o výzkumu proměnných hvězd a exoplanet, Praha, Czech Republic)
September 2016 - Gális, R., Merc J., Leedjärv, L. Spectroscopic view on the outburst activity of the symbiotic binary AG Draconis. (Astronoomia seminarid, Tartu Observatoorium, Tõravere, Estonia)
June 2016 - Gális, R., Hric, L., Leedjärv, L., Merc, J. Spektroskopický výskum aktivity symbiotického systému AG Draconis. (Conference about successes of stellar astronomy “Bezovec 2016″, Slovakia)

2015

November 2015 - Gális, R., Hric, L., Leedjärv, L., Merc, J. Spectroscopic view on the outburst activity of the symbiotic binary AG Draconis. (47. konference o výzkumu proměnných hvězd a exoplanet, Ostrava, Czech Republic)
December 2015 – Merc, J., Gális, R., Leedjärv, L. Correlation analysis of photometric and spectroscopic data of symbiotic systems AG Dra and Z And. (International meeting on variable star research “Kolos 2015″, Slovakia)
December 2015 – Gális, R., Hric, L., Leedjärv, L., Merc, J. Spectroscopic view on the outburst activity of the symbiotic binary AG Draconis. (International meeting on variable star research “Kolos 2015″, Slovakia)
June 2015 - Gális, R., Hric, L., Leedjärv, L., Merc, J. Outburst activity driven by evolved pulsating star in the symbiotic binary AG Draconis. (Physics of Evolved Stars 2015, Nice, France)
June 2015 – Merc, J., Gális, R., Leedjärv, L. Spectroscopic research of symbiotic binary star AG Dra. (Conference about successes of stellar astronomy “Bezovec 2015″, Slovakia)

Posters

2021

June 2021 – Gális, R., Merc, J., Leedjärv, L. Active and quiescent stages of the symbiotic system AG Draconis. (European Astronomical Society Annual Meeting 2021, Leiden, Netherlands, held online)
June 2021 - Merc, J., Mikołajewska, J., Gromadzki, M., Gałan, C., Iłkiewicz, K., et al. Gaia18aen: First symbiotic binary discovered by Gaia (European Astronomical Society Annual Meeting 2021, Leiden, Netherlands, held online)
March 2021 – Merc, J., Gális, R., Wolf, M. Characterising cool giants in symbiotic binaries using the Gaia EDR3 data. (The 20.5th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, held online)

2020

September 2020 – Merc, J., Gális, R., Wolf, M. New Online Database of Symbiotic Variables. (Royal Astronomical Society Early Career Poster Exhibition. United Kingdom, held online)
June 2020 – Merc, J., Gális, R., Teyssier, F. A need for long-term spectroscopic data in the investigation of symbiotic binaries. (European Astronomical Society Annual Meeting 2020, Leiden, Netherlands, held online)
June 2020 – Merc, J., Gális, R., Wolf, M. Characterizing the symbiotic population using the Gaia data. (European Astronomical Society Annual Meeting 2020, Leiden, Netherlands, held online)
June 2020 – Gális, R., Merc, J., Leedjärv, L. Clumpy environment around accreting compact objects in symbiotic systems. (European Astronomical Society Annual Meeting 2020, Leiden, Netherlands, held online)

2019

June 2019 – Gális, R., Merc, J., Leedjärv, L. Accretion-related winds in the symbiotic stars with Z And-type outburst activity. (European Week of Astronomy and Space Science 2019, Lyon, France)

Grants

Actual grants

APVV-20-0148 – 2021-2025 – From Interacting Binaries to Exoplanets
VVGS-PF-2021-1746 – 2021-2022 – Comprehensive research of selected symbiotic candidates in the Milky Way and Magellanic Clouds
GAUK 890120 – 2020-2022 – Population of symbiotic binaries in the Galaxy and Magellanic Clouds
SVV-260587 – 2020-2022 – Current problems of theoretical physics, astronomy and astrophysics
COST Action CA18104 – 2019-2023 – Revealing the Milky Way with Gaia
COST Action CA16117 – 2017-2021 – Chemical Elements as Tracers of the Evolution of the Cosmos

Previous grants

VVGS-PF-2019-1047 – 2019-2020 – Multi-frequency research of selected symbiotic binaries
APVV-15-0458 – 2016-2020 – Interacting binaries: the key to understanding of the universe
SVV-260441 – 2017-2019 – Current problems of theoretical physics, astronomy and astrophysics

Education

Sep 2018 - present

PhD in Astrophysics

Charles University in Prague, Czech Republic
P. J. Šafárik University in Košice, Slovakia

PhD thesis: Multifrequency investigation of symbiotic binaries
Supervisors: Marek Wolf & Rudolf Gális

Sep 2016 - May 2018

Master of Astrophysics

P. J. Šafárik University in Košice, Slovakia

Master thesis: Spectroscopic activity of the symbiotic binary AG Draconis (in Slovak language)
Supervisor: Rudolf Gális

Sep 2013 - June 2016

Bachelor of Physics

P. J. Šafárik University in Košice, Slovakia

Bachelor thesis: Spectroscopic investigation of the symbiotic binary AG Draconis (in Slovak language)
Supervisor: Rudolf Gális

CONTACT Me

Address

Astronomical Institute of Charles University
V Holešovičkách 2
180 00 Prague, Czech Republic

Email

merc@sirrah.troja.mff.cuni.cz
jaroslav.merc@student.upjs.sk

Jaroslav Merc

Research Interests

Symbiotic Binaries

Cataclysmic Variables

White Dwarfs

Supernovae Ia

Papers & Talks

Papers

2021

2020

2019

2018

2017

2016

Talks

2021

2020

2019

2018

2017

2016

2015

Posters

2021

2020

2019

Software

Grants

Actual grants

Previous grants

Education

PhD in Astrophysics

Master of Astrophysics

Bachelor of Physics

CONTACT Me

Address

Email