Fig. 2. Variability of T CrB in the UBV bands on 2009 February 27.
UBV observations of the flickering
of T CrB
ATel #2586
R. Zamanov, S. Boeva, S.
Tsvetkova, K. Stoyanov (Institute of Astronomy, Sofia, Bulgaria)
We observed the recurrent nova T Coronae Borealis simultaneously
in three filters (UBV) using the telescopes of the National
Astronomical
Observatory Rozhen (Bulgaria). The 2m RCC telescope observed in U and V
bands,
and the 50/70 cm Schmidt telescope in B band. During the first run (JD
2454851.6) the total amplitude detected in U was about 0.4 mag and
during the second (JD 2454889.5) – about 0.3 mag. In the table are
given as follows: the band, UT-start and UT-end of the run, exposure
time, number of CCD images obtained, minimum, maximum and average
magnitudes
in each band, standard
deviation of the mean, typical observational error.
The data can be downloaded from
http://www.astro.bas.bg/~rz/TCrB/TCrB.UBV.flick.tar.gz
We adopt extinction E(B-V)=0.15
(Selvelli, Cassatella & Gilmozzi, 1992, ApJ 393, 289).
Following Bruch (1992, A&A 266, 237), we calculate the dereddened
colours of
the flickering source:
January 20 (U-B)0 =
-0.50, (B-V)0
= +0.42;
February 27
(U-B)0 = -0.56, (B-V)0 = +0.59;
the
error is ±0.10 in U-B, and ±0.15 in B-V.
The result
confirm our resent findings (Zamanov et al. 2010, MNRAS 404, 381)
that the colours of the flickering source of the symbiotic stars
differ from those of the cataclysmic variables.
|
date |
UTst-end |
exp |
Npts |
min |
max |
average |
stdev |
err. |
|
band |
h:mm-h:mm |
[sec] |
|
[mag] |
[mag] |
[mag] |
[mag] |
[mag] |
|
20.01.2009 |
|
|
|
|
|
|
|
|
|
U |
2:17-4:05 |
180 |
28 |
11.517 |
11.921 |
11.747 |
0.118 |
0.027 |
|
B |
2:28-4:07 |
10 |
240 |
11.108 |
11.269 |
11.199 |
0.035 |
0.010 |
|
V |
2:19-4:09 |
5 |
559 |
9.878 |
9.952 |
9.916 |
0.015 |
0.016 |
|
27.02.2009 |
|
|
|
|
|
|
|
|
|
U |
0:11-1:37 |
180 |
24 |
12.162 |
12.465 |
12.330 |
0.089 |
0.028 |
|
B |
0:15-1:43 |
40 |
24 |
11.438 |
11.521 |
11.482 |
0.021 |
0.005 |
|
V |
0:10-1:40 |
7 |
490 |
10.138 |
10.191 |
10.168 |
0.009 |
0.012 |
Fig.1. Variability of T CrB
in the UBV bands on 2009
January 20.
Fig. 2. Variability of T CrB in the UBV bands on 2009
February 27.