SDSS J040714.78-064425.1: an eclipsing cataclysmic
Observed: 30 Nov, 13, 14, 22, 23, 24, 25 Dec 2006, 12, 13 Jan 2007
1 Dec 2006
Updated 23, 28 Dec 2006, 13, 25 Jan 2007
Time series for this deeply eclipsing cataclysmic
system are presented.
SDSS J040714.78-064425.1 is a cataclysmic system, that is a binary system
with an accreting white dwarf. Its discovery was reported in 2003. It has a 4-hr
orbital period with mag 2 deep eclipses.
This is a CBA
target for Nov 2006-Jan 2007.
The observations were carried out with a 203mm f/6.3 SC telescope,
a Clear filter and a SBIG ST7E camera (KAF401E CCD).
Each exposure has a duration of 200s. 265 images were obtained.
The comparison star is GSC 4731-00077 with an assumed unfiltered
magnitude of 15. The check star is UCAC2 29-394-440 at RA=04h07mn19.58s
DEC=-06°45'23.2" with an observed magnitude of 15.66
and a standard deviation of 0.10.
An example of an image:
Blue circle: SDSS J0407, Yellow square: comparison star, Blue tick: check star.
From my location, SDSS J0407 is observed through the geostationary
orbit, then the 5 satellite trails. Actually a number of observations
were lost because of trails on the variable or on the comparison star.
An example of a light curve:
Red: SDSS J0407; Blue: the check star, shifted by +4 mag. The error
bars are +/- the 1-sigma statistical uncertainties. The 4 spikes for the
check star are due to the many geostationary satellites visible from
my location in the direction of SDSS J0407.
All the light curves are HERE.
Ak et al (2004) observed 12 eclipses and derived the ephemeris:
T(HJD) = 2,452,949.1504(6) + 0.17017(3)*E
I observed the following 5 eclipses at HJD - 2454000:
This can be used to improve the ephemeris:
T(HJD) = 2452949.1503(6) + 0.1701785(2)*E
The resulting phase plot:
Red: Session 30 Nov 2006
Blue: 22 Dec 2006
Shifted by +3 magnitudes:
Brown: 25 Dec 2006
Magenta: 12 Jan 2007
Cyan: 13 Jan 2007
Excluding the eclipses, SDSS J0407 is observed varying between magnitudes
16 and 18:
The eclipses are removed from this light curve.
Ak T., Retter A., Liu A., Esenoglu H.H. (2004) arXiv:astro-ph/0412637.
Telescope and camera configuration.
Computer and software configuration.