AE Aqr flares (and HX Aqr)
Observed: 29, 30, 31 Aug 2005
31 Aug 2005
Updated: 1, 10 Sept 2005
Time-series of this unusual cataclysmic star were obtained with
B and V filters. Flares were observed, with strong color changes.
AE Aqr is a cataclysmic star, that is a binary with an accreting white
dwarf. The orbital period is 9.9h with a small inclination (no eclipse).
AE Aqr shows an oscillation with a very short period of 33s, which is
interpreted as the rotation period of the magnetic white dwarf.
From 28 Aug to 2 Sept 2005, there was an international, multiwavelength observation
campaign, with the following telescopes:
gamma-ray: HESS and MAGIC Cerenkov telescopes
X-ray: Chandra satellite
U-V: GALEX satellite
visible: VLT and other telescopes
radio: VLA radiotelescope.
Amateurs were invited to provide time-series, via the AAVSO
(AAVSO Alert Notice 326, 24/08/2005).
AE Aqr was also a CBA
target for Aug-Sept 2005.
Next to AE Aqr, the suspected eclipsing star HX Aqr was also observed.
The observations were carried out with a 203 mm f/6.3 SC telescope,
V and B filters used alternatively with a filter wheel and a SBIG ST7E
camera (KAF401E CCD). The exposure durations were 200s with the B filter,
60s with the V filter.
The comparison star is star 99 in the AAVSO chart 2035-01 (d), with
V=9.93 and B-V=0.147 (a very blue star). The check star K is GSC 5177-01044.
I also observed HX Aqr, a suspected eclipsing variable, which may be constant.
The light curves:
Green: the V magnitudes, Blue: the B magnitudes. The error bars are +/- the
1-sigma statistical uncertainties.
The light curves of the check star and of HX Aqr are HERE.
The B and V magnitudes are measured alternatively, not simultaneously.
To compute B-v at time t, the B and V magnitudes are interpolated.
The measured magnitudes are corrected for the transformations coefficients:
B = b + Tb*Tbv*[(b - v) - (Bc - Vc)]
V = B - [(Bc - Vc) + Tbv*[(b - v) - (Bc - Vc)]]
where b, v are the measured magnitudes, Bc, Vc the magnitudes of the comparison
star. Tb and Tbv are the transformations coefficients. They were measured
on 7 Jan 2005 from the Landolt 95 field with the same telescope, camera
Tbv = 0.967
Tb = -0.043
The resulting B-V variations:
Telescope and camera configuration.
Computer and software configuration.