A5106263324- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Astronomical and nuclear sciences
- Historical Astronomy and Related Studies
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Ancient Near East History
- Adaptive optics and wavefront sensing
- Pulsars and Gravitational Waves Research
- Cephalopods and Marine Biology
- Paleontology and Stratigraphy of Fossils
- Cosmology and Gravitation Theories
- Hungarian Social, Economic and Educational Studies
- Atmospheric and Environmental Gas Dynamics
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- High-pressure geophysics and materials
Konkoly Observatory
2015-2024
Research Centre for Astronomy and Earth Sciences
2015-2024
Hungarian Research Network
2021-2023
Hungarian Academy of Sciences
2011-2020
Hadtörténeti Intézet és Múzeum
2019
Max Planck Society
2018
Odesa I. I. Mechnikov National University
2009
Saint Mary's University
2009
Stillwater (Canada)
2009
Abbey Ridge Observatory
2009
The Gaia second Data Release (DR2) presents a first mapping of full-sky RR Lyrae stars and Cepheids observed by the spacecraft during initial 22 months science operations. Specific Object Study (SOS) pipeline, developed to validate fully characterise (SOS Cep&RRL) Gaia, has been presented in documentation papers accompanying Release. Here we describe how SOS pipeline was modified allow for processing multiband (G, G_BP G_RP) time series photometry all-sky candidate variables produce specific...
Context. Gaia has been in operations since 2014. The third data release expands from the early (EDR3) 2020 by providing 34 months of multi-epoch observations that allowed us to probe, characterise and classify systematically celestial variable phenomena. Aims. We present a summary variability processing analysis photometric spectroscopic time series 1.8 billion sources done for DR3. Methods. used statistical Machine Learning methods sources. Training sets were built global revision major...
Gaia DR3 contains 1.8 billion sources with G-band photometry, 1.5 of which BP and RP complemented by positions on the sky, parallax, proper motion. The median number field-of-view transits in three photometric bands is between 40 44 measurements per source covers 34 months data collection. We pursue a classification Galactic extra-galactic objects that are detected as variable across whole sky. Supervised machine learning (eXtreme Gradient Boosting Random Forest) was employed to generate...
The Gaia second Data Release (DR2) presents a first mapping of full-sky RR Lyrae stars and Cepheids observed by the spacecraft during initial 22 months science operations. Specific Object Study (SOS) pipeline, developed to validate fully characterise (SOS Cep&RRL) Gaia, has been presented in documentation papers accompanying Release. Here we describe how SOS pipeline was modified allow for processing multiband (G, G_BP G_RP) time series photometry all-sky candidate variables produce...
The Gaia Data Release 2 (DR2): we summarise the processing and results of identification variable source candidates RR Lyrae stars, Cepheids, long period variables (LPVs), rotation modulation (BY Dra-type) delta Scuti & SX Phoenicis short-timescale variables. In this release aim to provide useful but not necessarily complete samples candidates. processed data consist G, BP, RP photometry during first 22 months operations as well positions parallaxes. Various methods from classical...
Gaia DR3 publishes a catalogue of full-sky RR Lyrae stars (RRLs) observed during the initial 34 months science operations, that were processed through Specific Object Study (SOS) pipeline for Cepheids and RRLs (SOS Cep&RRL) by Gaia. The SOS Cep&RRL validation candidate relies on tools include Period (P) G-amplitude diagram P-phi21 -phi31 parameters G light curve Fourier decomposition, based sample bona fide known (Gold Sample). processing led to 271779 listed in vari_rrlyrae table DR3. By...
Context. Cepheids are pulsating stars that play a crucial role in several astrophysical contexts. Among the different types, Classical fundamental tools for calibration of extragalactic distance ladder. They also powerful stellar population tracers context Galactic studies. The Gaia Third Data Release (DR3) publishes improved data on collected during initial 34 months operations. Aims. We present DR3 catalogue all obtained through analysis carried out with Specific Object Study (SOS) Cep&RRL...
Context. The European Space Agency spacecraft Gaia is expected to observe about 10 000 Galactic Cepheids and over 100 Milky Way RR Lyrae stars (a large fraction of which will be new discoveries), during the five-year nominal lifetime spent scanning whole sky a faint limit G = 20.7 mag, sampling their light variation on average 70 times.
The second $Gaia$ Data Release (DR2) contains astrometric and photometric data for more than 1.6 billion objects with mean $G$ magnitude $<$20.7, including many Young Stellar Objects (YSOs) in different evolutionary stages. In order to explore the YSO population of Milky Way, we combined DR2 database WISE Planck measurements made an all-sky probabilistic catalogue YSOs using machine learning techniques, such as Support Vector Machines, Random Forests, or Neural Networks. Our input 103...
Context. Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important classes of variable used as standard candles to estimate galactic extragalactic distances. Their multiplicity is imperfectly known, particularly for RRLs. Astoundingly, date only one RRL has convincingly been demonstrated be a binary, TU UMa, out tens thousands known Aims. Our aim detect the binary multiple present in sample Milky Way CCs Methods. In article, we combine H IPPARCOS Gaia DR2 positions determine mean...
We report the detection of a rare transiting brown dwarf with mass 59 MJup and radius 1.1 RJup around metal-rich, [Fe/H] = +0.44, G9V star CoRoT-33. The orbit is eccentric (e 0.07) period 5.82 d. companion, CoRoT-33b, thus new member in so-called desert. orbital within 3% to 3:2 resonance rotational star. CoRoT-33b may be an important test case for tidal evolution studies. true frequency dwarfs close their host stars (P< 10 d) estimated approximately 0.2% which about six times smaller than...
Context. The multiplicity of classical Cepheids (CCs) and RR Lyrae stars (RRLs) is still imperfectly known, particularly for RRLs. Aims. In order to complement the close-in short orbital period systems presented in Paper I, our aim detect wide, spatially resolved companions targets reference samples Galactic CCs Methods. Angularly common proper motion pairs were detected using a simple progressive selection algorithm separate most probable candidate from unrelated field stars. Results. We...
Abstract We present the first analysis of Cepheid stars observed by TESS space mission in Sectors 1–5. Our sample consists 25 pulsators: ten fundamental mode, three overtone and two double-mode classical Cepheids, plus type II seven anomalous Cepheids. The targets were chosen from fields with different stellar densities, both Galactic field Magellanic System. Three have 2 minutes cadence light curves available Science Processing Operations Center: for rest, we prepared custom full-frame...
Context. The Gaia third Data Release (DR3) presents the first catalogue of full-sky variable Young Stellar Object (YSO) candidates observed by space telescope during initial 34 months science operations. Aims. Numerous types stars were classified using photometric data collected Gaia. One new classes presented in DR3 is class YSOs showing brightness variability. We analysed 79 375 sources as YSO to validate their young nature and investigate completeness purity sample. Methods. cross-matched...
<i>Context. <i/> The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. <i>Aims. We attempt to revise period-amplitude (<i>P<i/>-<i>A<i/>) relationship Galactic Cepheids based multi-colour photometric and radial velocity data. Reliable <i>P<i/>-<i>A<i/> graphs for constructed <i>U<i/>, <i>B<i/>, <i>V<i/>, <i>R<i/><sub>C<sub/>, <i>I<i/><sub>C<sub/> bands pulsational variations facilitate investigations previously poorly studied interrelations...
The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a pulsating the fundamental mode one first overtone with Canadian MOST satellite. 3.7-d period pulsator (RT Aur) has light curve that repeats precisely, can be modeled by Fourier series accurately. (SZ Tau, 3.1 d period) on other hand shows from cycle to which characterize variations parameters. We present arguments are seeing instability...
We present a detailed analysis of the bright Cepheid-type variable star V1154 Cygni using 4 yr continuous observations by Kepler space telescope. detected 28 frequencies standard Fourier transform method. identified modulation main pulsation frequency and its harmonics with period ∼159 d. This is also in parameters light curve O − C diagram. another about 1160 The shows significant power low-frequency region that we as granulation noise. effective time-scale agrees extrapolated scalings red...
The distance to pulsating stars is classically estimated using the parallax-of-pulsation (PoP) method, which combines spectroscopic radial velocity measurements and angular diameter estimates derive of star. An important application this method determination Cepheid distances, in view calibration their scale. However, conversion pulsational velocities PoP relies on a poorly calibrated parameter, projection factor (p-factor). We aim measure empirically value p-factors homogeneous sample nine...