THE ASTRONOMER Electronic Circular No 410         1990 May 10 17.57UT
Ed:Guy M Hurst, 16,Westminster Close,  Kempshott Rise,   Basingstoke,
Hants, RG22 4PP, England. Telephone:   (0256)471074  Int:+44256471074
Telex: 94082518 Answerback: TAGUY                 Microlink: MAG60138
JANET:GMH @ UK.AC.CAM.ASTRONOMY.STARLINK or GUYH@UK.AC.SUSSEX.CLUSTER
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TA 1990 APRIL ISSUE
It is regretted that our usual printers have let us down in printing
the April issue. Although the masters were finished as long ago as
April 15, the printers had still not completed the printing when I
checked a few days ago. I now understand that Roger Clark hopes to
despatch the magazine by the end of this week. Apologies for this
inconvenience and I welcome any suggestions for helping us out of
this continuing problem.
 
DWARF NOVA ALERT
Following the successful PRO-AM exchange with astronomers at Oxford
(cf E400) Janet Drew reports as follows:
"We used the second of our two shifts to observe IR Gem.  These were,
I believe, the first UV observations of this system in outburst. I
have not yet seen the spectra we obtained as my collaborator, Frank
Verbunt, still has them in Utrecht.  The aim of the observations was
to look for UV resonance line profile variations that might be linked
to orbital phase.  Frank has mailed me that the CIV 1549 profiles
were certainly variable - it remains to be seen if the variations are
on the orbital timescale.  We are interested in the properties of the
UV resonance lines because they are formed primarily by the winds
present in DN in outburst and nova-like variables. These winds almost
certainly originate from the inner portion of the accretion disk
and/or accreting white dwarf, but it is not yet clear how they are
powered, just how much mass they carry away (as a fraction of the
mass accretion rate) or what their precise geometry is.  Orbital
phase linked line profile variation is indicative of departures from
axial symmetry.  A while back, Frank and I initiated an observing
programme that would result in the compilation of a sample of DN (in
outburst) and nova-like variables that would enable us to assess the
general character of the wind/disk geometry giving rise to different
degrees of line profile variability in different systems.  The
programme continues next year (5 more IUE shifts allocated)".
 
DX AND
This variable was reported in outburst in 1989 Nov (cf E362).
Professional astronomers in Oxford wish to be alerted when the
star next begins to rise. Please let me know if a chart is needed
and telephone if an outburst starts.
 
Guy M Hurst