51 research outputs found
Mechanism of PbSe y S1 - Y film formation in chemical deposition from aqueous solutions
The growth mechanism of PbSe y S1 - y films has been studied upon chemical deposition from aqueous solutions using scanning probe microscopy. A comparative morphological analysis of layers deposited at the initial growth stages and the use of fractal formalism shows that the formation of films of PbS, PbSe, and PbSe y S1 - y substitutional solid solutions involves cluster-cluster aggregation with self-organization elements. © 2013 Pleiades Publishing, Ltd
Discovery of a bright microlensing event with planetary features towards the Taurus region: a super Earth planet
The transient event labeled as TCP J05074264+2447555 recently discovered
towards the Taurus region was quickly recognized to be an ongoing microlensing
event on a source located at distance of only pc from Earth. Here, we
show that observations with high sampling rate close to the time of maximum
magnification revealed features that imply the presence of a binary lens system
with very low mass ratio components. We present a complete description of the
binary lens system which hosts an Earth-like planet with most likely mass of
M. Furthermore, the source estimated location and
detailed Monte Carlo simulations allowed us to classify the event as due to the
closest lens system, being at a distance of pc and mass M.Comment: Accepted for publication on MNRAS, 2018. 6 Pages, 5 Figures.
References update
Superoutburst of a New Sub-Period-Minimum Dwarf Nova CSS130418 in Hercules
Multicolour photometry of a new dwarf nova CSS130418 in Hercules, which underwent superoutburst on April 18, 2013, allow to classified it as a WZ Sge-type dwarf nova. The phase light curves for different stages of superoutburst are presented. The early superhumps were used to determine the orbital period Porb = 64.84(1) minutes, which is shorter than the period minimum ~78 minutes for normal hydrogen-rich cataclysmic variables. We found the mean period of ordinary superhumps Psh = 65.559(1) minutes. The quiescent spectrum is rich in helium, showing double peaked emissionlines of H I and He I from accretion disk, so the dwarf nova is in a late stage of stellar evolution
Photometric and spectral studies of the eclipsing polar CRTS CSS081231 J071126+440405
© 2016, Pleiades Publishing, Ltd.We present the results of the study of the eclipsing polar CRTS CSS081231 J071126+440405. Photometric observations allowed us to refine the orbital period of the system (Formula presented.). Considerable changes in the appearance of the object’s spectra have occurred over the period of September 20–21, 2001: the slope of the continuum changed from “red” to “blue”, and the variability of the line profiles over the duration of the orbital period has also changed. Doppler maps have shown a shift of the emission line-forming region along the accretion stream closer to the white dwarf. We measured the duration of the eclipse of the system and imposed constraints on the inclination angle (Formula presented.). The derived radial velocity amplitude was used to obtain the basic parameters of the system: M1 = 0.86 ± 0.08M⊙, M2 = 0.18 ± 0.02 M⊙, q = 0.21 ± 0.01, RL2 = 0.20 ± 0.03 R⊙, A = 0.80 ± 0.03 R⊙. The spectra of the object exhibit cyclotron harmonics. Their comparison with model spectra allowed us to determine the parameters of the accretion column: B = 31–34 MG, Te = 10–12 keV, θ = 80–90°, and Λ = 105
Discovery of a WZ Sge-Type Dwarf Nova, SDSS J102146.44+234926.3: Unprecedented Infrared Activity during a Rebrightening Phase
Several SU UMa-type dwarf novae, in particular, WZ Sge-type stars tend to
exhibit rebrightenings after superoutbursts. The rebrightening phenomenon is
problematic for the disk instability theory of dwarf novae since it requires a
large amount of remnant matter in the disk even after superoutbursts. Here, we
report our optical and infrared observations during the first-ever outburst of
a new dwarf nova, SDSS J102146.44+234926.3. During the outburst, we detected
superhumps with a period of 0.056281 +/- 0.000015 d, which is typical for
superhump periods in WZ Sge stars. In conjunction with the appearance of a
long-lived rebrightening, we conclude that the object is a new member of WZ Sge
stars. Our observations, furthermore, revealed infrared behaviors for the first
time in the rebrightening phase of WZ Sge stars. We discovered prominent
infrared superhumps. We calculate the color temperature of the infrared
superhump source to be 4600-6400 K. These temperatures are too low to be
explained with a fully-ionized disk appearing during dwarf nova outbursts. We
also found a Ks-band excess over the hot disk component. These unprecedented
infrared activities provide evidence for the presence of mass reservoir at the
outermost part of the accretion disk. We propose that a moderately high
mass-accretion rate at this infrared active region leads to the long-lived
rebrightening observed in SDSS J102146.44+234926.3.Comment: 11 pages, 10 figures. Accepted for publication in PAS
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VIII: The Eighth Year (2015-2016)
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we
collected times of superhump maxima for 128 SU UMa-type dwarf novae observed
mainly during the 2015-2016 season and characterized these objects. The data
have improved the distribution of orbital periods, the relation between the
orbital period and the variation of superhumps, the relation between period
variations and the rebrightening type in WZ Sge-type objects. Coupled with new
measurements of mass ratios using growing stages of superhumps, we now have a
clearer and statistically greatly improved evolutionary path near the terminal
stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel,
ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to
reflect the slow growth of the 3:1 resonance near the stability border.
ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6 and CRTS J200331.3-284941
are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae.
ASASSN-15cy has a short (~0.050 d) superhump period and appears to belong to EI
Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn,
ASASSN-15hn, ASASSN-15kh and ASASSN-16bu are candidate period bouncers with
superhump periods longer than 0.06 d. We have newly obtained superhump periods
for 79 objects and 13 orbital periods, including periods from early superhumps.
In order that the future observations will be more astrophysically beneficial
and rewarding to observers, we propose guidelines how to organize observations
of various superoutbursts.Comment: 123 pages, 162 figures, 119 tables, accepted for publication in PASJ
(including supplementary information
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