MBCAA Observatory

AE Aqr flares (and HX Aqr)

Observed: 29, 30, 31 Aug 2005

Michel. Bonnardeau
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.

B-V variations

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 and filters:

Tbv = 0.967
Tb = -0.043

The resulting B-V variations:

Technical notes

Telescope and camera configuration.

Computer and software configuration.

Site map


Copyright notice

The observations were submitted to the AAVSO International Database, observer BZU.

The observations were used in Mauche et al (2011) Mem SAIt 33 1.

More observations in 2012.

MBCAA Observatory. Copyright 2004-2017