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 --------------------------------------------------------------------- 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