[vsnet-chat 6291] PZ Nor, a mistaken CV?

Dear readers,

Triggered by the 'apparent' bright state of PZ Nor on CCD images, I made visual observations of it on the night 2-3 May 2003, simultaneous with another CCD image recording.

The observed brightness's for PZ Nor were 14.4v and 12.3CR (the same as two nights ago) against sequences based on UCAC1 magnitudes.

The CV atlas gives a range 14.9p - 15.5p.

All this points to PZ Nor being red and in view of this:

1. the given blue magnitude range corresponds to an actually very small variability, which was confirmed by timeseries at CBA Pretoria on 1-2 May 2003.

2. 12.3 CR would convert to somewhere around 13.0 R

3. 14.4v (with darkadaption) would be around 14.0 V

4. from the p magnitudes the blue magnitude could be estimated to be around 15.5 B.

Therefore PZ Nor looks like a more or less constant 'star' at 14.0V with B-V=1.5. Possibly it is a CV with a large secondary, perhaps a nearby system with a quiet primary?

Someone with proper photometric filters could improve on the above results and produce a more factual conclusion. Any takers?

Note that PZ Nor has a close neighbour to the North, which will somehow have affected the above observations.

Regards,

Berto Monard

Bronberg Observatory / CBA Pretoria