This Alert Notice has been edited to correct a typographical error, and to correct the statement that the LMC was not well placed for coverage from Chile; AAVSO coverage was requested to broaden the coverage in longitude. Apologies for the errors - EOW
March 14, 2018: Dr. Frederick Walter (Stony Brook University) has requested AAVSO observers, particularly those in South Africa, Australia, and New Zealand, to monitor the current outburst of the recurrent nova Nova LMC 1996 = OGLE-2018-NOVA-01.
The progenitor of this nova has eclipses every 2.85 days. Observations of the current outburst indicate that the eclipse appears to be out of phase. To confirm this, optical photometry is needed urgently, beginning immediately.
Dr. Walter writes: "Nightly observations for the [next] month or two [through 2018 May 15] would be most useful, since it's only up for a few hours at the start of the night. V is fine - in fact, a long time series in one band is preferable to a mixture. However, if [an observer] has the filters, a BVRI sequence each night would be better than B alone (I'm getting BVRIJHK from Chile). And if possible, sitting on it for a couple of hours when it is eclipsing would be useful. But we do not know the ephemeris well yet - just the period (2.85 days)."
In order to extend the coverage in longitude, observers in South Africa, Australia, and New Zealand are urged to observe the nova as it declines. The current outburst is only the second one detected in Nova LMC 1996 (P. Mroz and A. Udalski on behalf of the OGLE team, (ATel #11384). Spectroscopy by Walter shows the nova is an optically thin He-N nova (ATel #11390).
L. Chomiuk et al. (ATel #11392) report that ASAS-SN monitoring of the LMC shows the present outburst was undetected down to <16.3 V before 2018 February 25. On 2018 February 25.16 UT, it was in outburst at V = 11.0 mag.
Dr. Walter reports that on March 11 Nova LMC 1996 was magnitude ~14.7 V, and on March 12 it was magnitude 16.4 V (in eclipse?), and is fading.
Coordinates (2000.0): R.A. 05 13 32.71 Dec. -68 38 00.4
Charts with a comparison star sequence for Nova LMC 1996 may be plotted using the AAVSO Variable Star Plotter (VSP). A finder chart showing the nova (but without comparison stars) prepared by Dr. Walter is available at:
http://www.astro.sunysb.edu/fwalter/SMARTS/NovaAtlas/nlmc1996/nlmc1996.html
Please submit observations to the AAVSO International Database using the name NOVA LMC 1996.
This observing campaign is being followed on the AAVSO Campaigns and Observing Reports online forum at: https://www.aavso.org/nova-lmc-1996-observations-2018
This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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