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Special Notice #183: Update on Nova Eri 2009 [KT Eri]

AAVSO Special Notice #183

Update on Nova Eri 2009

November 29, 2009

Contrary to my expectations, this transient object [KT Eri] appears to be a true nova.

H. Maehara, Kwasan Observatory, Kyoto University, reported in CBET 2053 that a low-resolution spectrum shows Halpha in emission with FWHM of 3400km/s.  M. Fujii reported on another spectrum that gives an Halpha FWHM of 3200 km/s, and other emission lines that suggest He/N nova classification; this classification was also suggested by Rudy et al., CBET 2055, from NIR spectra.

In addition, Kasia Malek of the "Pi of the Sky" consortium, reported in [vsnet-alert 11695,11696] that their system obtained photometry of the nova from 2009/11/13 through 2009/11/26UT, with the object reaching a peak Cousins-R magnitude of Rc=5.60 on 2009/11/14.  This gives an outburst amplitude of about 9 magnitudes, reasonable for a nova.

Bright Star Monitor photometry on 2009/11/28 gave rough colors and magnitude of V=8.38, (B-V) = -0.18, (V-Rc) = 0.63, (Rc-Ic) = 0.028, (V-Ic) = 0.67, showing the influence of the bright Halpha line.  This probably also influences the Pi-of-the-Sky magnitudes.

These factors taken together strongly suggest that this is a classical He/N nova, about two weeks after maximum.  Being bright and in a good observing location for the next few months, this nova should be followed extensively until the end of the season.  CCD observers should use filters, preferably V and B; visual observers should be alert for any flaring activity.  As suggested by R. Huziak, many meteor observers acquiring images of the Leonid meteor shower may have early photometry, which will be especially valuable if the images were taken in RAW mode on DSLRs.  Since this nova has a bright progenitor, you may also have images from earlier periods, and there may be existing published photometry that can be data-mined.

Charts with comparison stars can be generated with VSP, and observations can be submitted with names 000-BJR-847, VSX J044754.2-101043, or N Eri 2009.  We will be updating the comparison stars to give more accurate photometry and Rc/Ic bandpasses as soon as the weather improves in the Southwestern U.S.

Arne Henden

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