Special Notice #50: Second update on V5558 Sgr

June 28, 2007

V5558 Sgr, a slow nova that has been rising since April (see Special Notices 44, 45, and 48) exhibited a brief brightening over the past few days, and may now be trending downwards. The most recent observations as of this notice place the star at V ~ 8.1 at JD 2454280.0 after reaching m(vis) ~ 7.8. Both visual and CCD observers are strongly encouraged to continue monitoring this peculiar object; BVRI observations are especially encouraged, as they will provide important information on the spectral evolution of this nova. We will add comparison stars to VSP if and when it brightens beyond the current bright limit of the chart (mag 7.6). We note that the extremely slow nova V723 Cas (Nova Cas 1995) exhibited a short rapid rise before finally beginning to decline about 100 days after outburst, and a similar event may be happening here.

Coordinates are: RA 18:10:18.26, Dec -18:46:51.9 (J2000)

Please report observations to the AAVSO as 1804-18 V5558 SGR.

Matthew Templeton

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