@article{MTMT:34125272,
	title = {Type W and Type 15bn Subgroups of Hydrogen-poor Superluminous Supernovae: Premaximum Diversity, Postmaximum Homogeneity?},
	url = {https://m2.mtmt.hu/api/publication/34125272},
	author = {Könyves-Tóth, Réka and Seli, Bálint Attila},
	doi = {10.3847/1538-4357/ace787},
	journal-iso = {ASTROPHYS J},
	journal = {ASTROPHYSICAL JOURNAL},
	volume = {954},
	unique-id = {34125272},
	issn = {1538-4357},
	abstract = {In this study, we analyze the postmaximum spectra of a sample of 27 Type I superluminous supernovae (SLSNe-I) in order to search for physical differences between the so-called Type W and Type 15bn subtypes. This paper is a continuation of Konyves-Toth & Vinko and Konyves-Toth. In the former, it was revealed that not all SLSNe-I show the W-shaped absorption feature between 4000 and 5000 & ANGS; in the premaximum spectra, and two new SLSN subgroups were disclosed. In the latter, physical differences in the premaximum phases were studied. For completeness, postmaximum data are analyzed in this paper. It is concluded that in terms of photospheric temperature and velocity, Type W and Type 15bn SLSNe-I decrease to a similar value by the postmaximum phases, and their pseudo-nebular spectra are nearly uniform. The relation between the photometric and spectroscopic phases (& phi;) between the two subgroups was examined, and it was found that the & phi; of Type W SLSNe-I increases monotonically with time, while Type 15bn objects tend to show larger & phi; before peak brightness, which evolves slowly. Pseudo-equivalent width (pEW) calculations show that the pEWs of the wavelength range between 4166 and 5266 & ANGS; evolve differently in the cases of the two subtypes, while the other parts of the spectra seem to evolve similarly. It was found that the host galaxies of the studied objects do not differ significantly in their star formation rate, morphology, stellar mass, and absolute brightness. The main difference behind the bimodality of Type W and Type 15bn SLSNe-I therefore is in their premaximum evolution.},
	year = {2023},
	eissn = {0004-637X},
	orcid-numbers = {Seli, Bálint Attila/0000-0002-3658-2175}
}

@article{MTMT:34053151,
	title = {EI Eridani: A star under the influence. The effect of magnetic activity in the short and long term},
	url = {https://m2.mtmt.hu/api/publication/34053151},
	author = {Kriskovics, Levente and Kővári, Zsolt and Seli, Bálint Attila and Oláh, Katalin Ilona and Vida, Krisztián and Henry, G. W. and Granzer, T. and Görgei, A.},
	doi = {10.1051/0004-6361/202245767},
	journal-iso = {ASTRON ASTROPHYS},
	journal = {ASTRONOMY & ASTROPHYSICS},
	volume = {674},
	unique-id = {34053151},
	issn = {0004-6361},
	abstract = {Context. Homogeneous photometric time series spanning decades provide a unique opportunity to study the long-term cyclic behavior of active spotted stars such as our target EI Eridani. In addition, with ultraprecise space photometry data, it is possible to investigate the accompanying flare activity in detail. However, the rotation period of ≈2 days for EI Eri makes it impossible to achieve time-resolved surface images from a single ground-based observing site. Therefore, for this purpose, spectroscopic data from a multi-site observing campaign are needed.},
	year = {2023},
	eissn = {1432-0746},
	orcid-numbers = {Kővári, Zsolt/0000-0001-5160-307X; Seli, Bálint Attila/0000-0002-3658-2175; Görgei, A./0009-0002-1289-7946}
}

@article{MTMT:33538419,
	title = {Characteristics of flares on giant stars},
	url = {https://m2.mtmt.hu/api/publication/33538419},
	author = {Oláh, Katalin Ilona and Seli, Bálint Attila and Kővári, Zsolt and Kriskovics, Levente and Vida, Krisztián},
	doi = {10.1051/0004-6361/202243789},
	journal-iso = {ASTRON ASTROPHYS},
	journal = {ASTRONOMY & ASTROPHYSICS},
	volume = {668},
	unique-id = {33538419},
	issn = {0004-6361},
	abstract = {Context. Although late-type dwarfs and giant stars are substantially different, their flares are thought to originate in similar physical processes and differ only by a scale factor in the energy levels. We study the validity of this approach.},
	year = {2022},
	eissn = {1432-0746},
	orcid-numbers = {Seli, Bálint Attila/0000-0002-3658-2175; Kővári, Zsolt/0000-0001-5160-307X}
}

@article{MTMT:33535919,
	title = {Erratum: “A New Sample of Warm Extreme Debris Disks from the ALLWISE Catalog” (2021, ApJ, 910, 27)},
	url = {https://m2.mtmt.hu/api/publication/33535919},
	author = {Moór, Attila and Ábrahám, Péter and Szabó M., Gyula and Vida, Krisztián and Cataldi, Gianni and Derekas, Alíz and Henning, Thomas and Kinemuchi, Karen and Kóspál, Ágnes and Kovács, József and Pál, András and Sarkis, Paula and Seli, Bálint Attila and Szabó, Zsófia M. and Takáts, Katalin},
	doi = {10.3847/1538-4357/aca280},
	journal-iso = {ASTROPHYS J},
	journal = {ASTROPHYSICAL JOURNAL},
	volume = {940},
	unique-id = {33535919},
	issn = {1538-4357},
	year = {2022},
	eissn = {0004-637X},
	orcid-numbers = {Szabó M., Gyula/0000-0002-0606-7930; Cataldi, Gianni/0000-0002-2700-9676; Derekas, Alíz/0000-0002-6526-9444; Henning, Thomas/0000-0002-1493-300X; Kinemuchi, Karen/0000-0001-7908-7724; Sarkis, Paula/0000-0001-8128-3126; Seli, Bálint Attila/0000-0002-3658-2175; Szabó, Zsófia M./0000-0001-9830-3509}
}

@article{MTMT:33108812,
	title = {Mid-infrared time-domain study of recent dust production events in the extreme debris disc of TYC 4209-1322-1},
	url = {https://m2.mtmt.hu/api/publication/33108812},
	author = {Moór, Attila and Ábrahám, Péter and Kóspál, Ágnes and Su, Kate Y. L. and Rieke, George H. and Vida, Krisztián and Cataldi, Gianni and Bódi, Attila and Sódorné Bognár, Zsófia and Cseh, Borbála and Csörnyei, Géza and Egei, Nóra and Farkas, Anikó and Hanyecz, Ottó and Ignácz, Bernadett and Kalup, Csilla and Könyves-Tóth, Réka and Kriskovics, Levente and Mészáros, László and Pál, András and Ordasi, András and Sárneczky, Krisztián and Seli, Bálint Attila and Sódor, Ádám and Szakáts, Róbert and Vinkó, József and Zsidi, Gabriella},
	doi = {10.1093/mnras/stac2595},
	journal-iso = {MON NOT R ASTRON SOC},
	journal = {MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY},
	volume = {516},
	unique-id = {33108812},
	issn = {0035-8711},
	abstract = {Extreme debris discs are characterized by unusually strong mid-infrared excess emission, which often proves to be variable. The warm dust in these discs is of transient nature and is likely related to a recent giant collision occurring close to the star in the terrestrial region. Here we present the results of a 877 days long, gap-free photometric monitoring performed by the Spitzer Space Telescope of the recently discovered extreme debris disc around TYC 4209-1322-1. By combining these observations with other time-domain optical and mid-infrared data, we explore the disc variability of the last four decades, with particular emphasis on the last 12 years. During the latter interval the disc showed substantial changes, the most significant was the brightening and subsequent fading between 2014 and 2018 as outlined in WISE data. The Spitzer light curves outline the fading phase and a subsequent new brightening of the disc after 2018, revealing an additional flux modulation with a period of ~39 days on top of the long-term trend. We found that all these variations can be interpreted as the outcome of a giant collision that happened at an orbital radius of ~0.3 au sometime in 2014. Our analysis implies that a collision on a similar scale could have taken place around 2010, too. The fact that the disc was already peculiarly dust rich 40 years ago, as implied by IRAS data, suggests that these dust production events belong to a chain of large impacts triggered by an earlier even more catastrophic collision.},
	keywords = {infrared: planetary systems; (stars:) circumstellar matter; stars: individual: TYC 4209-1322-1},
	year = {2022},
	eissn = {1365-2966},
	pages = {5684-5701},
	orcid-numbers = {Bódi, Attila/0000-0002-8585-4544; Seli, Bálint Attila/0000-0002-3658-2175; Vinkó, József/0000-0001-8764-7832}
}

@CONFERENCE{MTMT:33087071,
	title = {Stellar FIP effect from the empirical side},
	url = {https://m2.mtmt.hu/api/publication/33087071},
	author = {Seli, Bálint Attila and Van Driel Gesztelyi, Lídia and Baker, Deborah and Laming, J. Martin and Kővári, Zsolt and Oláh, Katalin Ilona and Kriskovics, Levente and Vida, Krisztián and Balázs, Lajos},
	booktitle = {44th COSPAR Scientific Assembly. Held 16-24 July},
	unique-id = {33087071},
	abstract = {The difference between the elemental abundances of the corona and the photosphere is an apparently common feature of stellar atmospheres. The abundance difference depends on the first ionization potential of the given element, so the phenomenon is known as the FIP effect. Here we explore the variation of the strength of the FIP effect for different types of stars, through the FIP bias parameter. Using a sample of 59 main sequence and evolved stars with known coronal abundances from the literature, we look for macroscopic, measurable parameters that affect the stellar FIP bias, and also re-evaluate the simple dependence on the effective temperature.},
	year = {2022},
	orcid-numbers = {Seli, Bálint Attila/0000-0002-3658-2175; Kővári, Zsolt/0000-0001-5160-307X}
}

@article{MTMT:33087067,
	title = {A Multi-epoch, Multiwavelength Study of the Classical FUor V1515 Cyg Approaching Quiescence},
	url = {https://m2.mtmt.hu/api/publication/33087067},
	author = {Szabó, Zs. M. and Kóspál, Ágnes and Ábrahám, Péter and Park, Sunkyung and Siwak, Michal and Green, J. D. and Pál, András and Acosta-Pulido, J. A. and Lee, J. -E. and Ibrahimov, M. and Grankin, K. and Kovács, B. and Bora, Zs. and Bódi, Attila and Cseh, Borbála and Csörnyei, Géza and Dróżdż, Marek and Hanyecz, O. and Ignácz, B. and Kalup, Csilla and Könyves-Tóth, Réka and Krezinger, Máté and Kriskovics, Levente and Ogłoza, Waldemar and Ordasi, A. and Sárneczky, Krisztián and Seli, Bálint Attila and Szakáts, Róbert and Sódor, Ádám and Szing, A. and Vida, Krisztián and Vinkó, József},
	doi = {10.3847/1538-4357/ac82f5},
	journal-iso = {ASTROPHYS J},
	journal = {ASTROPHYSICAL JOURNAL},
	volume = {936},
	unique-id = {33087067},
	issn = {1538-4357},
	abstract = {Historically, FU Orionis-type stars are low-mass, pre-main-sequence stars. The members of this class experience powerful accretion outbursts and remain in an enhanced accretion state for decades or centuries. V1515 Cyg, a classical FUor, started brightening in the 1940s and reached its peak brightness in the late 1970s. Following a sudden decrease in brightness, it stayed in a minimum state for a few months, then started brightening for several years. We present the results of our ground-based photometric monitoring complemented with optical/near-infrared spectroscopic monitoring. Our light curves show a long-term fading with strong variability on weekly and monthly timescales. The optical spectra show P Cygni profiles and broad blueshifted absorption lines, common properties of FUors. However, V1515 Cyg lacks the P Cygni profile in the Ca II 8498 Å line, a part of the Ca infrared triplet, formed by an outflowing wind, suggesting that the absorbing gas in the wind is optically thin. The newly obtained near-infrared spectrum shows the strengthening of the CO bandhead and the FeH molecular band, indicating that the disk has become cooler since the last spectroscopic observation in 2015. The current luminosity of the accretion disk dropped from the peak value of 138 L ⊙ to about 45 L ⊙, suggesting that the long-term fading is also partly caused by the dropping of the accretion rate.},
	keywords = {SPECTROSCOPY; photometry; Astrophysics - Solar and Stellar Astrophysics; YOUNG STELLAR OBJECTS; CIRCUMSTELLAR DISKS; INFRARED ASTRONOMY; FU Orionis stars; 1834; 553; 1558; optical astronomy; 1234; 235; 786; 1776},
	year = {2022},
	eissn = {0004-637X},
	orcid-numbers = {Bódi, Attila/0000-0002-8585-4544; Seli, Bálint Attila/0000-0002-3658-2175; Vinkó, József/0000-0001-8764-7832}
}

@article{MTMT:32732997,
	title = {Complex Modulation of Rapidly Rotating Young M Dwarfs: Adding Pieces to the Puzzle},
	url = {https://m2.mtmt.hu/api/publication/32732997},
	author = {Günther, Maximilian N. and Berardo, David A. and Ducrot, Elsa and Murray, Catriona A. and Stassun, Keivan G. and Oláh, Katalin Ilona and Bouma, L. G. and Rappaport, Saul and Winn, Joshua N. and Feinstein, Adina D. and Matthews, Elisabeth C. and Sebastian, Daniel and Rackham, Benjamin V. and Seli, Bálint Attila and Triaud, Amaury H. M. J. and Gillen, Edward and Levine, Alan M. and Demory, Brice-Olivier and Gillon, Michaël and Queloz, Didier and Ricker, George R. and Vanderspek, Roland K. and Seager, Sara and Latham, David W. and Jenkins, Jon M. and Brasseur, C. E. and Colón, Knicole D. and Daylan, Tansu and Delrez, Laetitia and Fausnaugh, Michael and Garcia, Lionel J. and Jayaraman, Rahul and Jehin, Emmanuel and Kristiansen, Martti H. and Kruijssen, J. M. Diederik and Pedersen, Peter Pihlmann and Pozuelos, Francisco J. and Rodriguez, Joseph E. and Wohler, Bill and Zhan, Zhuchang},
	doi = {10.3847/1538-3881/ac503c},
	journal-iso = {ASTRON J},
	journal = {ASTRONOMICAL JOURNAL},
	volume = {163},
	unique-id = {32732997},
	issn = {0004-6256},
	keywords = {1681; 982; 1290; 1603; 1580; 1629; 1761; 1213; 1572},
	year = {2022},
	eissn = {1538-3881},
	orcid-numbers = {Seli, Bálint Attila/0000-0002-3658-2175}
}

@article{MTMT:32726535,
	title = {Extending the FIP bias sample to magnetically active stars},
	url = {https://m2.mtmt.hu/api/publication/32726535},
	author = {Seli, Bálint Attila and Oláh, Katalin Ilona and Kriskovics, Levente and Kővári, Zsolt and Vida, Krisztián and Balázs, Lajos and Laming, J. M. and Van Driel Gesztelyi, Lídia and Baker, D.},
	doi = {10.1051/0004-6361/202141493},
	journal-iso = {ASTRON ASTROPHYS},
	journal = {ASTRONOMY & ASTROPHYSICS},
	volume = {659},
	unique-id = {32726535},
	issn = {0004-6361},
	abstract = {Context. The different elemental abundances of the photosphere and the corona are striking features of not only the Sun, but of other stars as well. This phenomenon is known as the first ionisation potential (FIP) effect, and its strength can be characterized by the FIP bias, the logarithmic abundance difference between low- and high-FIP elements in the corona, compared to the photosphere. The FIP bias was shown to depend on the surface temperature of the star. Aims: We aim to extend the Teff−FIP bias relationship to a larger stellar sample and analyse the effect of other astrophysical parameters on the relation (e.g. surface gravity, age, activity indicators). Methods: We compiled FIP bias and other parameters for 59 stars for which coronal composition is available, now including evolved stars. Using principal component analysis and linear discriminant analysis, we searched for correlations with other astrophysical parameters within the sample that may influence the stellar FIP bias. Results: Adding stars to the Teff−FIP bias diagram unveiled new features in its structure. In addition to the previously known relationship, there appears to be a second branch: a parallel sequence about 0.5 dex above it. While the Teff remains the main determinant of the FIP bias, other parameters such as stellar activity indicators also have influence. We find three clusters in the FIP bias determinant parameter space. One distinct group is formed by the evolved stars. Two groups contain main sequence stars in continuation separated roughly by the sign change of the FIP-bias value. Conclusions: The new branch of the Teff−FIP bias diagram contains stars with higher activity level, in terms of X-ray flux and rotational velocity. The Rossby number also seems to be important, indicating possible dependence on the type of dynamo operating in these stars influencing their FIP bias. The two main-sequence clusters run from the earliest spectral types of A-F with shallow convection zones through G-K-early-M stars with gradually deeper convection zones, and they end with the fully convective M dwarf stars, depicting the change of the dynamo type with the internal differences of the main sequence stars in connection with the FIP-bias values.},
	year = {2022},
	eissn = {1432-0746},
	orcid-numbers = {Seli, Bálint Attila/0000-0002-3658-2175; Kővári, Zsolt/0000-0001-5160-307X}
}

@article{MTMT:32559296,
	title = {Triply eclipsing triple stars in the northern TESS fields: TICs 193993801, 388459317, and 52041148},
	url = {https://m2.mtmt.hu/api/publication/32559296},
	author = {Borkovits, Tamás and Mitnyan, Tibor and Rappaport, S A and Pribulla, T and Powell, B P and Kostov, V B and Bíró, Imre Barna and Csányi, István and Garai, Zoltán and Gary, B L and Kaye, T G and Komžík, R and Terentev, I and Omohundro, M and Gagliano, R and Jacobs, T and Kristiansen, M H and LaCourse, D and Schwengeler, H M and Czavalinga, Donát Róbert and Seli, Bálint Attila and Huang, C X and Pál, András and Vanderburg, A and Rodriguez, J E and Stevens, D J},
	doi = {10.1093/mnras/stab3397},
	journal-iso = {MON NOT R ASTRON SOC},
	journal = {MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY},
	volume = {510},
	unique-id = {32559296},
	issn = {0035-8711},
	abstract = {In this work we report the discovery and analysis of three new triply eclipsing triple star systems found with the TESS mission during its observations of the northern skies: TICs 193993801, 388459317, and 52041148. We utilized the TESS precision photometry of the binary eclipses and third-body eclipsing events, ground-based archival and follow-up photometric data, eclipse timing variations, archival spectral energy distributions, as well as theoretical evolution tracks in a joint photodynamical analysis to deduce the system masses and orbital parameters of both the inner and outer orbits. In one case (TIC 193993801) we also obtained radial velocity measurements of all three stars. This enabled us to 'calibrate' our analysis approach with and without 'truth' (i.e. RV) data. We find that the masses are good to 1-3 per cent accuracy with RV data and 3-10 per cent without the use of RV data. In all three systems we were able to find the outer orbital period before doing any detailed analysis by searching for a longer-term periodicity in the ASAS-SN archival photometry data - just a few thousand ASAS-SN points enabled us to find the outer periods of 49.28 d, 89.86 d, and 177.0 d, respectively. From our full photodynamical analysis we find that all three systems are coplanar to within 1 degrees-3 degrees. The outer eccentricities of the three systems are 0.003, 0.10, and 0.62, respectively (i.e. spanning a factor of 200). The masses of the three stars {Aa, Ab, and B} in the three systems are: {1.31, 1.19, 1.34}, {1.82, 1.73, 2.19}, and {1.62, 1.48, 2.74} M-circle dot, respectively.},
	year = {2022},
	eissn = {1365-2966},
	pages = {1352-1374},
	orcid-numbers = {Borkovits, Tamás/0000-0002-8806-496X; Mitnyan, Tibor/0000-0001-5803-3938; Pribulla, T/0000-0003-3599-516X; Garai, Zoltán/0000-0001-9483-2016; Seli, Bálint Attila/0000-0002-3658-2175}
}