A5010037298- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Inertial Sensor and Navigation
- High-pressure geophysics and materials
- Geophysics and Sensor Technology
- Calibration and Measurement Techniques
- Historical Astronomy and Related Studies
- Spacecraft Design and Technology
- Nuclear Physics and Applications
- Scientific Research and Discoveries
- Space Exploration and Technology
- Diverse Scientific and Economic Studies
- Advanced X-ray and CT Imaging
- Molecular Spectroscopy and Structure
- Atomic and Subatomic Physics Research
Nicolaus Copernicus Astronomical Center
2015-2024
Polish Academy of Sciences
2014-2024
Graz University of Technology
2018
University of Vienna
2004-2013
South African Radio Astronomy Observatory
1999-2009
Ames Research Center
2009
Search for Extraterrestrial Intelligence
2009
Instituto de Astrofísica de Andalucía
2009
University of Central Lancashire
2009
Smithsonian Astrophysical Observatory
2009
Asteroseismology involves probing the interiors of stars and quantifying their global properties, such as radius age, through observationsof normal modes oscillation. The technical requirements for conducting asteroseismology include ultra-high precision measured in photometry parts per million, well nearly continuous time series over weeks to years, cadences rapid enough sample oscillations with periods shortas a few minutes. We report on results from first 43 days observations which unique...
Over the duration of Kepler mission, KIC8462852 was observed to undergo irregularly shaped, aperiodic dips in flux up $\sim 20$\%. The dipping activity can last for between 5 and 80 days. We characterize object with high-resolution spectroscopy, spectral energy distribution fitting, radial velocity measurements, imaging, Fourier analyses light curve. determine that is a typical main-sequence F3 V star exhibits no significant IR excess, has very close interacting companions. In this paper, we...
The Kepler spacecraft is providing time series of photometric data with micromagnitude precision for hundreds A-F type stars. We present a first general characterization the pulsational behaviour stars as observed in light curves sample 750 candidate propose three main groups to describe variety pulsating stars: gamma Dor, delta Sct, and hybrid assign 63% our one groups, identify remaining part rotationally modulated/active stars, binaries, different spectral type, or that show no clear...
Observations of the pulsations stars can be used to infer their interior structure and test theoretical models. The main-sequence γ Doradus (Dor) δ Scuti (Sct) with masses 1.2–2.5 M☉ are particularly useful for these studies. Dor pulsate in high-order g-modes periods order 1 day, driven by convective blocking at base envelope convection zone. Sct low-order g- p-modes 2 hr, κ mechanism operating He ii ionization Theory predicts an overlap region Hertzsprung–Russell diagram between instability...
We present an extensive and up-to-date catalog of Galactic β Cephei stars. This is intended to give a comprehensive overview observational characteristics all known stars, covering information until 2004 June. Ninety-three stars could be confirmed use data from more than 250 papers published over the last nearly 100 years, we provide 45 notes on individual For some reanalyzed or conducted our own analyses. Sixty-one were rejected final list, 77 are suspected A list critically selected...
BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, the brightness and temperature variations of stars generally brighter than mag(V) ≈ 4 with precision time coverage not possible from ground. The current design consists six nanosats (hence Constellation): Austria, Canada, Poland. Each 7 kg nanosat carries optical telescope aperture 3 cm feeding uncooled CCD. One instrument each pair...
We present results from the first two quarters of a survey to search for pulsations in compact stellar objects with Kepler spacecraft. The sample and various methods applied its compilation are described, spectroscopic observations presented separate into accurate classes. From photometry we clearly identify nine pulsators, number interesting binary stars. Of one shows strong, rapid typical V361 Hya type sdB variable (sdBV), seven show long-period characteristic V1093 Her sdBVs,...
The analysis of the light curves 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all which show low frequencies, characteristic slowly B (SPB) stars. Seven also a few weak, isolated high frequencies and they could be considered as SPB/β Cephei (β Cep) hybrids. In cases, frequency spectra quite different from what seen ground-based observations. We suggest that this because most modes degree predicted to unstable in models mid-B find there non-pulsating...
The Kepler Mission has acquired 33.5 d of continuous 1-min photometry KPD 1946+4340, a short-period binary system that consists subdwarf B star (sdB) and white dwarf. In the light curve, eclipses are clearly seen, with deepest occurring when compact dwarf crosses disc sdB (0.4 per cent) more shallow ones (0.1 As expected, is deformed by gravitational field dwarf, which produces an ellipsoidal modulation curve. Spectacularly, very strong Doppler beaming (also known as boosting) effect also...
The oscillation spectrum of ν Eri is the richest known for any variable β Cephei type. We interpret in terms normal mode excitation and construct seismic models star. frequency data combined with on mean colours set upper limit extent overshooting from convective core. use rotational splitting two dipole (ℓ= 1) modes (g1 p1) to infer properties internal rotation rate. Adopting a plausible hypothesis nearly uniform envelope increasing rate μ-gradient zone, we find that this zone about three...
In this paper we describe a new class of pulsating stars, the prototype which is bright, early, F‐type dwarf γ Doradus. These stars typically have between 1 and 5 periods ranging from 0.4 to 3 days with photometric amplitudes up 0.1 mag in Johnson V. The mechanism for these observed variations high‐order, low‐degree, nonradial, gravity‐mode pulsation.
70 new γ Doradus candidates were identified from Hipparcos photometry, which represents more than a doubling of the presently known number. Selecting objects with good evidence for multiperiodicity, it is found that these stars, together bona fide members class, occupy well-defined region in colour-magnitude diagram. This domain corresponds to range 7200–7700 K on zero-age main sequence (ZAMS) and 6900–7500 one magnitude above it, partly overlaps instability strip δ Scuti stars.
We searched for δ Scuti-type pulsations amongst known and candidate γ Doradus stars. The motivations such a project come from the need to understand relationship of these two classes pulsator better, present poor knowledge hot border phenomenon, exciting prospects asteroseismology should stars be found which have both types pulsation excited. acquired 270 h observations monitored total 26 One target, HD 209295, turned out member pulsating star, but this object is peculiar in sense that it...
The motivation, techniques and performance of the ground-based photometric follow-up transit detections by CoRoT space mission are presented. Its principal <i>raison d'être<i/> arises from much higher spatial resolution common telescopes in comparison to CoRoT's cameras. This allows identification many candidates as arising eclipsing binaries that contaminating lightcurves, even low-amplitude events cannot be detected with obervations. For ground observations, "on" – "off" photometry is now...
HD 187547 was the first candidate that led to suggestion solar-like oscillations are present in δ Scuti stars. Longer observations, however, show modes interpreted as have either very long mode lifetimes, longer than 960 days, or coherent. These results incompatible with nature of "pure" stochastic excitation observed Nonetheless, one point is certain: opacity mechanism alone cannot explain oscillation spectrum 187547. Here we new theoretical investigations showing convection dynamics can...
BRITE (BRIght Target Explorer) Constellation, the first nanosatellite mission applied to astrophysical research, is a collaboration among Austria, Canada and Poland. The fleet of satellites (6 launched, 5 functioning) performs precise optical photometry brightest stars in night sky. A pioneering like - with optics instruments restricted small volume, mass power several nanosatellites, whose measurements must be coordinated orbit poses many unique challenges. We discuss technical issues,...
We used extensive ground-based multisite and archival spectroscopy to derive observational constraints for a seismic modelling of the magnetic beta Cep star V2052 Ophiuchi. The line-profile variability is dominated by radial mode (f_1=7.14846 d^{-1}) rotational modulation (P_rot=3.638833 d). Two non-radial low-amplitude modes (f_2=7.75603 d^{-1} f_3=6.82308 are also detected. four periodicities that we found same as ones discovered from companion photometric campaign (Handler et al. 2012)...
Empirical evidence for the involvement of nonradial pulsations (NRP's) in mass loss from Be stars ranges (i) a singular case (\object{$\mu$ Cen}) repetitive ejections triggered by multi-mode beating to (ii) several photometric reports about enormous numbers pulsation modes popping up during outbursts and on (iii) effective single-mode pulsators. The BRITE Constellation nanosatellites was used obtain mmag photometry $\eta$ \object{$\mu$ Cen}. In low-inclination star Cen}, light pollution...
We present the first results from Transiting Exoplanet Survey Satellite (TESS) on rotational and pulsational variability of magnetic chemically peculiar A-type stars. analyse TESS 2-min cadence data sectors 1 2 a sample 83 Five new rapidly oscillating Ap (roAp) stars are announced. One these pulsates with periods around 4.7 min, making it shortest period roAp star known to date. Four out five multiperiodic. Three singly periodic one show presence mode splitting. Individual frequencies...
We report a multisite photometric campaign for the Beta Cephei star 12 Lacertae. 750 hours of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with 9 telescopes during 190 nights. Our frequency analysis results in detection 23 sinusoidal signals light curves. Eleven those correspond to independent pulsation modes, remainder are combination frequencies. find some slow aperiodic variability such as that seemingly present several stars....
Extensive photometric multisite campaigns of the δ Scuti variable FG Vir are presented.For years 2003 and 2004, 926 h photometry at millimag precision level were obtained.The combinations with earlier lead to excellent frequency resolution high signal/noise.A multifrequency analysis yields 79 frequencies.This represents a new record for this type star.The modes discovered confirmed.Pulsation occurs over wide band from 5.7 44.3 c/d amplitudes 0.2 mmag or larger.Within frequencies not...
From 5.5 months of dual-band optical photometric monitoring at the 1 mmag level, BRITE-Constellation has revealed two simultaneous types variability in O4I(n)fp star ζ Puppis: one single periodic non-sinusoidal component superimposed on a stochastic component. The monoperiodic is 1.78-d signal previously detected by Coriolis/Solar Mass Ejection Imager, but this time along with prominent first harmonic. shape changes over time, behaviour that incompatible stellar oscillations consistent...
Context. The BRIght Target Explorer (BRITE) mission is a pioneering space project aimed at the long-term photometric monitoring of brightest stars in sky by means constellation nanosatellites. Its main advantage high accuracy and time coverage which are inaccessible from ground. drawback lack cooling CCD detectors absence good shielding that would protect them energetic particles.