[vsnet-chat 1408] Star x near Nova Sco 1998

[Mati Morel <morel@ozemail.com.au>]

Hi all,
        In vsnet-alert 2312 I introduced three lettered comparison stars for
Nova Sco
1998 - x, y and z. I have suggested that x may not be a good choice, being
possibly
double (its image looks elongated on HDE chart 177, compared to the round
images of
neighbouring stars). Albert Jones has also raised the question of colour,
the Tycho
magnitudes, VT and BT, differ by about 2.1mag. A very red star?
        Fiurter checking reveals this data:
* "x" is not listed as a carbon star.
* DM identifications:
        x = CoD-31 14795 (9.7) 
        y = CoD-30 14924 (9.6) = CPD-30 5026 (9.6)
        z = CoD-30 14921 (9.7) = CPD-30 5023 (9.2)
        
        x is not listed in the CPD, not surprising as red stars of around 10.0v
are often omitted from the blue-sensitive CPD catalogue.

        So, the star(s) known as "x" would appear to have a red component.

        I have Guide 7 on order, but until it arrives I cannot really comment on
the usefulness of Tycho mags at the 10mag level. What little I know has been
gleaned from other observers' posts.

Regards,

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