Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userColours of the flickering source of Mira
108
0
0.0
(
0
)
Added by
Radoslav K. Zamanov
Publication date
2019
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We report photometric observations in Johnson UBV bands of the short term variability of Mira. The amplitude detected is 0.16 mag in B band. Adopting interstellar extinction E(B-V)=0, we find for the flickering source colour B-V=1.3, temperature T=3700 K, and radius R=0.77 Rsun. The colour of the flickering source is considerably redder than the average B-V colour of the cataclysmic variables.
rate research
Read More
We performed photometry with a 1 minute time resolution of the symbiotic stars EF Aquilae, AG Pegasi and SU Lyncis in Johnson B and V band. Our observations of the symbiotic Mira-type star EF Aql demonstrate the presence of stochastic light variations with an amplitude of about 0.25 magnitudes on a time scale of 5 minutes. The observations prove the white dwarf nature of the hot component in the binary system. It is the 11th symbiotic star (among more than 200 symbiotic stars known in our Galaxy) which displays optical flickering. For SU Lyn we do not detect flickering with an amplitude above 0.03 mag in B band. For AG Peg, the amplitude of variability in B and V band is smaller than 0.05 mag and 0.04 mag respectively.
Here we present quasi-simultaneous observations of the flickering of the symbiotic binary star CH Cyg in U, B and V bands. We calculate the flickering source parameters and discuss the possible reason for the flickering cessation in the period 2010-2013.
We report observations of the flickering variability of the recurrent nova RS Oph at quiescence on the basis of simultaneous observations in 5 bands (UBVRI). RS Oph has flickering source with (U-B)_0=-0.62 pm 0.07, (B-V)_0=0.15 pm 0.10, (V-R)_0=0.25 pm 0.05. We find for the flickering source a temperature T_fl = 9500 pm 500 K, and luminosity L_fl = 50 - 150 L_sun (using a distance of d=1.6kpc). We also find that on a (U-B) vs (B-V) diagram the flickering of the symbiotic stars differs from that of the cataclysmic variables. The possible source of the flickering is discussed. The data are available upon request from the authors and on the web www.astro.bas.bg/~rz/RSOph.UBVRI.2010.MNRAS.tar.gz.
We report observations of the flickering variability of the dwarf nova RX And in five bands (UBVRI) on two nights. On 25 October 2019 the brightness of the star was $Bapprox 13.9$ mag, the amplitude of the flickering was 0.47 mag, and we estimate for the flickering source temperature $T_{fl} = 10700 pm 400$ K, and radius $R_{fl} =0.046 pm 0.004$ $R_odot$. On 2 January 2020, the star was about 3 magnitudes brighter ($B approx 10.7$), the amplitude of the flickering was significantly lower (0.07 mag) and we derive for the flickering source $T_{fl} = 9600 pm 700$ K, and radius $R_{fl} = 0.098 pm 0.009$ $R_odot$. The results indicate that 3 magnitudes brightening of the star doubled the radius of the flickering source. The data are available upon request from the authors.
We analyse optical photometric data of short term variability (flickering) of the accreting white dwarf in the jet-ejecting symbiotic star MWC560. The observations are obtained in 17 nights during the period November 2011 - October 2019. The colour-magnitude diagram shows that the hot component of the system becomes redder as it gets brighter. For the flickering source we find that it has colour 0.14 < B-V < 0.40, temperature in the range 6300 < T_fl < 11000 K, and radius 1.2 < R_fl < 18 Rsun. We find a strong correlation (correlation coefficient 0.76, significance < 0.001) between B band magnitude and the average radius of the flickering source - as the brightness of the system increases the size of the flickering source also increases. The estimated temperature is similar to that of the bright spot of cataclysmic variables. In 2019 the flickering is missing, and the B-V colour of the hot component becomes bluer.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
