Explanipedia

SN 2023ixf in M101: Physical Parameters from Bolometric Light Curve Modeling Open

J. Vinkó, Zsofia R. Bodola, Ákos Gődény, Szelina Fruzsina Csák, Réka Könyves-Tóth , et al. · 2025

We present new photometric observations of the core-collapse supernova SN 2023ixf occurred in M101, taken with the RC 80 and BRC80 robotic telescopes in Hungary. The initial nickel mass from the late-phase bolometric light curve extending …

The elusive chase for the first RR Lyr star in a binary system: the case of KIC 2831097 Open

E. Poretti, J. F. Le Borgne, Miguel Correa, Á. Sódor, M. Rainer , et al. · 2025

Context. The lack of RR Lyr stars in binary systems is an atypical fact when we consider other classes of variables. Therefore, it has become a challenge for observers to detect an RR Lyr variable in a binary system. Aims. The RR Lyr varia…

Time-resolved protoplanetary disk physics in DQ Tau with JWST Open

Á. Kóspál, P. Ábrahám, Vitaly Akimkin, Longyue Chen, J. Forbrich , et al. · 2025

Aims . Accretion variability is ubiquitous in young stellar objects. While large outbursts (2.5–6 mag) may strongly affect the disk structure, the effects of moderate bursts (1–2.5 mag) are less understood. Our aim is to characterize the p…

Selected Results on Variable Stars Observed by TESS Open

Zsófia Bognár, Á. Sódor · 2025

As we enter the final year of the second extended mission of the Transiting Exoplanet Survey Satellite (TESS), it is time to reflect on what the TESS mission has contributed to the advancement of astronomy. Thousands of papers based on TES…

Selected Results on Variable Stars Observed by TESS Open

Zsófia Bognár, Á. Sódor · 2025

As we enter the final year of the second extended mission of the Transiting Exoplanet Survey Satellite (TESS), it is time to reflect on what the TESS mission has contributed to the advancement of astronomy. Thousands of papers based on TES…

The 2023 Outburst of the Gaia Alerted EXor Gaia23bab Open

Z. Nagy, Á. Kóspál, P. Ábrahám, T. Giannini, M. Kun , et al. · 2025

Episodic accretion is a fundamental process in the build-up of the stellar mass. EX Lupi-type eruptive young stars (EXors) represent one of the main types of episodic accretion. We study the recently discovered EXor Gaia23bab during its 20…

Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau Open

Gabriella Zsidi, Á. Kóspál, P. Ábrahám, E. Alécian, Silvia H. P. Alencar , et al. · 2025

Context. Classical T Tauri stars are newly formed, low-mass stars, which may display both periodic and random variations in their brightness. These systems are surrounded by a circumstellar disk, from which material falls onto the stellar …

Exoplanet atmospheres at high spectral resolution Open

Á. Sódor · 2025

High-resolution spectroscopy (HRS) has grown into one of the main techniques to characterise the atmospheres of extrasolar planets. High spectral resolving power allows for the efficient removal of telluric and host-star contamination. Com…

The 2023 outburst of the Gaia alerted EXor Gaia23bab Open

Z. Nagy, Á. Kóspál, P. Ábrahám, T. Giannini, M. Kun , et al. · 2025

Episodic accretion is a fundamental process in the build-up of the stellar mass. EX Lupi-type eruptive young stars (EXors) represent one of the main types of episodic accretion. We study the recently discovered EXor Gaia23bab during its 20…

Gaia20bdk – New FU Ori-type star in the Sh 2-301 star-forming region Open

M. Siwak, Á. Kóspál, P. Ábrahám, G. Marton, Paweł Zieliński , et al. · 2025

Context. We analyse multi-colour photometric and spectroscopic observations of the young stellar object (YSO) Gaia20bdk. Aims. We aim to investigate the exact nature of the eruptive phenomenon that the star has been undergoing since 2018. …

Gaia20bdk -- a new FUor in Sh 2-301 Star Forming Region Open

M. Siwak, Á. Kóspál, P. Ábrahám, G. Marton, Paweł Zieliński , et al. · 2024

Context. We analyse multi-colour photometric and spectroscopic observations of a Young Stellar Object Gaia20bdk. Aims. We aim to investigate the exact nature of the eruptive phenomenon that the star has been experiencing since 2018. Method…

Ejecta Masses in Type Ia Supernovae—Implications for the Progenitor and the Explosion Scenario* Open

Zsófia Bora, Réka Könyves-Tóth, J. Vinkó, D. Bánhidi, I Bíró , et al. · 2024

The progenitor system(s) as well as the explosion mechanism(s) of thermonuclear (Type Ia) supernovae are long-standing issues in astrophysics. Here we present ejecta masses and other physical parameters for 28 recent Type Ia supernovae inf…

Ejecta masses in Type Ia Supernovae -- Implications for the Progenitor and the Explosion Scenario Open

Zsófia Bora, Réka Könyves-Tóth, J. Vinkó, D. Bánhidi, I Bíró , et al. · 2024

The progenitor system(s) as well as the explosion mechanism(s) of thermonuclear (Type Ia) supernovae are long-standing issues in astrophysics. Here we present ejecta masses and other physical parameters for 28 recent Type Ia supernovae inf…

The enigma of Gaia18cjb: A possible rare hybrid of FUor and EXor properties Open

Eleonora Fiorellino, P. Ábrahám, Á. Kóspál, M. Kun, J. M. Alcalá , et al. · 2024

Context. Gaia18cjb is one of the Gaia -alerted eruptive young star candidates that has been experiencing a slow and strong brightening during the last 13 years, similarly to some FU Orionis-type objects. Aims. The aim of this work is to de…

Rotation of ZZ Ceti stars as seen by TESS Open

Zsófia Bognár, Á. Sódor · 2024

Context. Knowing the rotation rates and masses of white dwarf stars is an important step towards characterising the angular momentum transport mechanism in their progenitors, and coupling the cores of red giants to their envelopes. However…

Rotation of ZZ Ceti stars as seen by TESS Open

Zs. Bognár, Á. Sódor · 2024

Context. Knowing the rotation rates and masses of white dwarf stars is an important step towards characterising the angular momentum transport mechanism in their progenitors, and coupling the cores of red giants to their envelopes. However…

<i>TESS</i> Cycle 2 observations of roAp stars with 2-min cadence data Open

Daniel L. Holdsworth, M. S. Cunha, Mariel Lares-Martiz, D. W. Kurtz, V. Antoci , et al. · 2023

We present the results of a systematic search of the Transiting Exoplanet Survey Satellite (TESS) 2-min cadence data for new rapidly oscillating Ap (roAp) stars observed during the Cycle 2 phase of its mission. We find seven new roAp stars…

MELCHIORS Open

P. Royer, T. Merle, K. Dsilva, S. Sekaran, H. Van Winckel , et al. · 2023

Aims . Over the past decades, libraries of stellar spectra have been used in a large variety of science cases, including as sources of reference spectra for a given object or a given spectral type. Despite the existence of large libraries …

SN 2022oqm: A Bright and Multi-peaked Calcium-rich Transient Open

S. K. Yadavalli, V. Ashley Villar, L. Izzo, Yossef Zenati, R. J. Foley , et al. · 2023

We present the photometric and spectroscopic evolution of SN 2022oqm, a nearby multi-peaked hydrogen- and helium-weak calcium-rich transient (CaRT). SN 2022oqm was detected 13.1 kpc from its host galaxy, the face-on spiral galaxy NGC 5875.…

ZZ Ceti stars of the southern ecliptic hemisphere re-observed by TESS Open

Zsófia Bognár, Á. Sódor, Ian Clark, S. D. Kawaler · 2023

Context. In 2020, a publication presented the first-light results for 18 known ZZ Ceti stars observed by the TESS Space Telescope during the first survey observations of the southern ecliptic hemisphere. However, in the meantime, new measu…

The first view of δ Scuti and γ Doradus stars with the TESS mission Open

V. Antoci, M. S. Cunha, D. M. Bowman, Simon J. Murphy, D. W. Kurtz , et al. · 2022

© 2019 The Author(s) We present the first asteroseismic results for δ Scuti and γ Doradus stars observed in Sectors 1 and 2 of the TESS mission. We utilize the 2-min cadence TESS data for a sample of 117 stars to classify their behaviour r…

GD 99: Re-investigation of an old ZZ Ceti companion Open

Zs. Bognár, Á. Sódor, György Mező · 2022

Context. Thanks to photometric space missions, we have access to more and more information on the properties of white dwarf stars, especially pulsating ones. In the case of pulsators, we have the opportunity to get an insight into their ot…

Mid-infrared time-domain study of recent dust production events in the extreme debris disc of TYC 4209-1322-1 Open

A. Moór, P. Ábrahám, Á. Kóspál, K. Y. L. Su, G. H. Rieke , et al. · 2022

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 clo…

A Multi-epoch, Multiwavelength Study of the Classical FUor V1515 Cyg Approaching Quiescence Open

Zsófia Marianna Szabó, Á. Kóspál, P. Ábrahám, Sunkyung Park, M. Siwak , et al. · 2022

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, s…

Periodic variable A-F spectral type stars in the northern TESS continuous viewing zone Open

M. Skarka, Jiří Žák, M. Fedurco, E. Paunzen, Z. Henzl , et al. · 2022

Context. In the time of large space surveys that provide tremendous amounts of precise data, it is highly desirable to have a commonly accepted methodology and system for the classification of variable stars. This is especially important f…

First Results on RR Lyrae Stars with the TESS Space Telescope: Untangling the Connections between Mode Content, Colors, and Distances Open

L. Molnár, Attila Bódi, András Pál, Anupam Bhardwaj, Franz-Josef Hambsch , et al. · 2021

The Transiting Exoplanet Survey Satellite (TESS) space telescope is collecting continuous, high-precision optical photometry of stars throughout the sky, including thousands of RR Lyrae stars. In this paper, we present results for an initi…

Ground-based observations of the ZZ Ceti star HS 1625+1231 Open

Csilla Kalup, Zsófia Bognár, Á. Sódor · 2021

We present the results of our detailed light curve analysis of the ZZ Ceti star HS 1625+1231. We collected photometric time series data at Konkoly Observatory on 14 nights, and performed Fourier analysis of these data sets. We detected 11 …

SN 2018agk: A Prototypical Type Ia Supernova with a Smooth Power-law Rise in Kepler (K2) Open

Qinan Wang, A. Rest, Yossef Zenati, Ryan Ridden-Harper, G. Dimitriadis , et al. · 2021

We present the 30 minutes cadence Kepler/K2 light curve of the Type Ia supernova (SN Ia) SN 2018agk, covering approximately one week before explosion, the full rise phase, and the decline until 40 days after peak. We additionally present g…

SN2017jgh: a high-cadence complete shock cooling light curve of a SN IIb with the <i>Kepler</i> telescope Open

P. Armstrong, B. Tucker, A. Rest, Ryan Ridden-Harper, Yossef Zenati , et al. · 2021

SN 2017jgh is a type IIb supernova discovered by Pan-STARRS during the C16/C17 campaigns of the Kepler/K2 mission. Here, we present the Kepler/K2 and ground based observations of SN 2017jgh, which captured the shock cooling of the progenit…

A comprehensive look at RR Lyrae stars through high-precision photometry and astrometry Open

L. Molnár, Attila Bódi, András Pál, Anupam Bhardwaj, Franz-Josef Hambsch , et al. · 2021

The TESS and Gaia missions are both collecting data of exquisite quality for RR Lyrae-type pulsating stars. We combine light curve shape information from TESS with distances and brightnesses from Gaia to build a detailed classification sch…

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