[vsnet-chat 1698] EP Carinae

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

Hi All,
        The star EP Car has been on the VSS,RASNZ program for some years,
and charts 
719 and 720 (Series 16) were issued in 1983.  It is either type M? or possibly a
nova (or nova like?) variable. Anyway, in spite of regular monitoring, it
has yet 
to be sighted.  Peter Williams asked me for some background info. on this
star. Its
doscovery was reported in BAN 4, 146 (1928). Brian Skiff kindly provided me
with a
transcript of the report in BAN. Enough observations were made to show that the
star certainly exists, and is at (or near) the position of a USNO-A2.0 star.
I am
happy to forward Brian's reply, for the benefit of other observers who may
wish to
observe EP Car.  Only lettered comparison stars exist in the immediate vicinity,
but RASNZ chart 719 shows a V sequence about 20' due south for YZ Car, range 9.3
to 13.1V.
EP Car : (2000) 10h28m23s -58 57.8'.  M?  13.0 -(16p

Regards,
Mati


>Date: Fri, 26 Feb 1999 01:21:33 -0700
>From: bas@lowell.edu (Brian Skiff)
>To: morel@ozemail.com.au
>Subject: EP Carinae
>
>     Hi Mati.  The Hertzsprung note (it is only a few sentences) is in BAN
>volume, 4, no. 146, page 172.  It is the note appended onto the final page
>of the article you evidently got that describes the various eclipsers, so
>perhaps you have that final page already.  The chart seems to point
>unambiguously to the USNO-A2.0 star at:  10 28 24.4  -58 58 01 (2000), mb=18.5,
>mr=16.5.  But there is clearly the possibility that EP Car could be a few
>arcseconds away, be very faint at minimum, and not appear in USNO-A.  In case
>you don't have the relevant page, here is H's complete text:
>
>     "The variable star EP Carinae, 10h23m49s.4  -58o19'.6 (1875) was formerly
>only found visible during ten days from JD 2423879.35 to 3889.47 and on one
>old plate from JD 2421722.27.  In addition to this I found EP Car visible on
>three MF Harvard plates and on four Johannesburg plates all from May 1926.
>Using the same comparison star as in BAN no. 77, page 209, the estimates are:
>
>plate         HJD         s
>MF10162   2424639.548   +1.1
>   3300      4642.348   -0.32
>   3301      4642.374   -0.35
>   3324      4648.240   +0.12
>MF10226      4648.552   -0.26
>   3328      4649.244   +0.75
>MF10233      4649.519    0.00
>     [presumably the column 's' is a step or some sort of magnitude]
>
>The last estimate on MF10233 is indicated as particularly uncertain.
>     "The two intervals between the three observed maxima are about 2160 and
>760 days.  No period is as yet apparent."
>
>
>     This looks to me more like superoutburst CV behavior than Mira-like
>variations.  Plenty of photometry in this field obviously, so it seems like
>you could use them to make an adjustment to the A2.0 magnitudes to get reliable
>V for some faint stars immediately around the variable.

>
>\Brian
>
>
/Mati

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