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Special Notice #83: X-ray Transient/Nova = V598 Pup; Possible Nova in Ser [V535 Ser]

November 20, 2007

1. X-ray Transient/Nova = V598 Pup

Further to AAVSO Special Notices #81 and #82, Nikolai Samus, Institute of Astronomy, Russian Academy of Sciences, announced (IAU Circular No. 8898, D. W. E. Green, ed.) that the bright x-ray transient and apparent nova has been assigned the name V598 Puppis [07:05:42.7 -38:14:42 (equinox 2000.0)].

Also as urged in Special Notices #81 and #82, filtered observations (V filter recommended) should be made for this star due to the emission seen in the spectra. Unfiltered observations may be subject to contamination from the emission.

Observations reported to the AAVSO to date include: 542 unfiltered time-series observations by Arto Oksansen, San Pedro de Atacama, Chile, covering the interval Nov. 19.2684 - 19.3737 UT and the magnitude range = 11.5646 - 11.6074, with an average magnitude = 11.5869; Nov. 19.506, 10.17V, W. Dillon, Missouri City, TX; Nov. 20.036, 9.9, A. Amorim, Florianopolis, Brazil (via IAU Circular 8898).

The name V598 PUP will become available for reporting observations to the AAVSO shortly. Until then, please continue to submit observations using the name VSX J070542.5-381439.


2. Possible Nova in Ser [V535 Ser]

IAU Circular 8898 (D. W. E. Green, ed.) announces that S. Nakano, Sumoto,Japan, reports that Koichi Nishiyama, Kurume, Fukuoka-ken, Japan, and Fujio Kabashima, Miyaki-cho, Saga-ken, Japan, "have found a variable star located at

R.A. = 18h09m24s.25, Decl. = -07o22'14".2 (equinox 2000.0)

with the following unfiltered CCD magnitudes (200-mm camera lens, except 40-cm reflector on Nov. 20): Oct. 2.485 UT, 12.8; 12.501, 12.3; Nov. 19.358, 10.5; 19.387, 10.7; 20.414, 11.2; 20.430, 11.1; 20.431, 11.0. A USNO-B1.0 catalogue star (mag 18.5) has position end figures 24s.30, 13".5."

ASAS 180924-0722.2 [18:09:24.0 -07:22:13.4 (J2000)], with a range of 13.6 - <15 V, shows a Mira-like light curve with a crude period of ~255 days, based on 3 cycles, including a gap of 509 days. Using the 255-day period and the ASAS3 data, the star should be around maximum on December 5.

Thus, this ASAS star could be the star reported by Nishimaya and Kabashima.

This Special Notice was prepared by Elizabeth O. Waagen.



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