A5079470184- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Geophysics and Gravity Measurements
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Methane Hydrates and Related Phenomena
- Geomagnetism and Paleomagnetism Studies
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Statistical and numerical algorithms
- History and Developments in Astronomy
- Radioactive Decay and Measurement Techniques
- Oceanographic and Atmospheric Processes
- Lattice Boltzmann Simulation Studies
- Dark Matter and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Fluid Dynamics and Turbulent Flows
- Astrophysics and Cosmic Phenomena
- Phase Equilibria and Thermodynamics
University of Warsaw
1997-2019
view Abstract Citations (198) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gravitational microlensing of the Galactic bulge stars Kiraga, Marcin ; Paczynski, Bohdan We estimate optical depth to gravitational due known stellar populations be approximately 8.5 x 10-7 for in Baade Window. The contribution and disk is 60% 40%, respectively, all numbers being uncertain. If mass function approximated as N(M) M-2 0.1 less than or equal M/Solar...
There are by now ten published detections of fast radio bursts (FRBs), single bright GHz-band millisecond pulses unknown origin. Proposed explanations cover a broad range from exotic processes at cosmological distances to atmospheric and terrestrial sources. Loeb et al. have previously suggested that FRB sources could be nearby flare stars, pointed out the presence W-UMa-type contact binary within beam one three fields they examined. Using time-domain optical photometry spectroscopy, we find...
The most abundant stars in the Galaxy, M dwarfs, are very commonly hosts to diverse systems of low-mass planets. Their abundancy implies that general occurrence rate planets is dominated by their around such dwarfs. In this article, we combine dwarf surveys conducted with HIRES/Keck, PFS/Magellan, HARPS/ESO, and UVES/VLT instruments supported data from several other instruments. We analyse radial velocities an approximately volume- brightness-limited sample 426 nearby dwarfs order search for...
AD Leonis is a nearby magnetically active M dwarf. We find Doppler variability with period of 2.23 days as well photometric signals: (1) short signal which similar to the radial velocity albeit considerable variability; and (2) long term activity cycle 4070$\pm$120 days. examine short-term in available ASAS MOST photometry that not consistently present varies considerably function time. This undergoes phase change roughly 0.8 rad when considering first second halves data set are separated...
Abstract The search for Earth-like planets around late-type stars using ultra-stable spectrographs requires a very precise characterization of the stellar activity and magnetic cycle star, since these phenomena induce radial velocity (RV) signals that can be misinterpreted as planetary signals. Among nearby stars, we have selected Barnard’s Star (Gl 699) to carry out set spectroscopic data covers about 14.5 years comes from seven different spectrographs: HARPS, HARPS-N, CARMENES, HIRES,...
Photometric data from the ASAS - South (declination less than 29 deg) survey have been used for identification of bright stars located near sources ROSAT All Sky Survey Bright Source Catalog (RBSC). In total 6028 brighter 12.5 mag in I- or V -bands selected and analyzed periodicity. Altogether 2302 variable found with periods ranging 0.137 d to 193 d. Most these X-ray emission coronal origin a few cataclysmic binaries early type colliding winds. Whenever it was possible we collected...
It was recently demonstrated that contact binaries occur in globular clusters (GCs) only immediately below turn-off point and the region of blue straggler stars (BSs). In addition, observations indicate at least a significant fraction BSs these formed by binary mass-transfer mechanism. The aim our present investigation is to obtain analyze set evolutionary models cool, close detached with low metal abundance, which are characteristic GC. We computed evolution 975 initially detached, cool...
Based on analysis of photometric observations nearby M type stars obtained with ASAS, 31 periodic variables were detected. The determined periods are assumed to be related rotation the investigated stars. Among them 10 new longer than days found, which brings total number slowly rotating known 12 objects. X-ray activity and evolution follows trends observed in G-K Rapidly very active decreases increasing period but period-activity relation is mass-dependent suggests that alone not a proper...
We have reanalyzed the OGLE V and I photometry of ~500,000 stars in Baade's Window, we confirm extinction map published by Stanek. However, find that interpretation color-magnitude diagram for disk proposed Paczyński et al. was incorrect: dominant population Window is old, no evidence a large hole inner Galactic disk. small systematic error below "red clump": (V-I) color indices faint with > 18 are too red ~0.1 mag. tentative from HST bulge main-sequence turnoff point brighter ~0.5 mag than...
We present a numerical study of the relation between cosmic peculiar velocity field and gravitational acceleration field. show that on mildly non-linear scales (4–10 h−1 Mpc Gaussian smoothing), distribution Cartesian coordinates each these fields is well approximated by Gaussian. In particular, their kurtoses negentropies are small compared to those divergence density fields. find at gravity follows linear theory good accuracy. Specifically, systematic errors in velocity—velocity...
We present a catalog of 307 optical counterparts the bright ROSAT X-ray sources, identified with ASAS North survey data and showing periodic brightness variations. They all have declination north -25 deg. Other available from literature for listed stars are also included. All tabulated new variables, except 13 previously known, which revised values periods given.
[Abridged] We test the evolutionary model of cool close binaries on observed properties near contact (NCBs). Those with a more massive component filling Roche lobe are SD1 whereas in SD2 is less massive. Our assumes that, following overflow by (donor), mass transfer occurs until ratio reversal. A binary an initial phase transfer, before equalization, identified binary. show that transferred forms equatorial bulge around (accretor). Its presence slows down rate to value determined thermal...