V442 Oph

Observed: 2, 8, 18, 25 June, 5, 16, 17 July, 5 August 2005

Michel Bonnardeau
1 July 2005
Updated: 6, 22 July, 17 August 2005

Abstract

Time-series for this anti-dwarf nova are presented.

Introduction

V442 Oph is a cataclysmic star, that is binary with an accreting white dwarf. In the Ritter + 2003 catalog of cataclysmic binaries (VizieR V/113A) it is classified as a Nova Like, of the VY Scl category (anti-dwarf nova whose brightness may fall by several magnitudes over extended periods). It is also of the SW Sex category (high inclination, peculiar spectroscopy). It is also listed as having an orbital period of 0.12433 day and another period of 0.12090 day.

V442 Oph is a CBA target for July 2005.

Observations

The observations were carried out with a 203 mm f/6.3 SC telescope, a SBIG ST7E camera (KAF401E CCD) and a Clear filter. 611 images were obtained. Each exposure is 1 mn long.

The comparison star is GSC 6235-02678 at RA=17h32mn11.93s DEC=-16°14'51.8" with an assumed unfiltered magnitude of 13.17. The check star is an anonymous star at RA=17h06mn06.92s DEC=-16°13'17.7" with a measured magnitude of 15.02 (standard deviation 0.11).

A sample image is here.

Light curves:


Red: V442 Oph, Green: the check star, shifted by +1.5 mag. The error bar are +/- 1 sigma the statistical uncertainties. The air mass was < 2.5.


The air mass was high at the end of the session (see below) but the sky clear.



The Moon at 34° and hazy sky.
Does the pulse-like feature disappears when the object becomes weak?

V442 Oph was also observed on June 8, 18, 25 under poor sky conditions, on July 17 (2 images) and on August 5 (1 image). The variation of the average magnitudes:

Technical notes

Telescope and camera configuration.

Software and computer configuration.