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X-ray nova

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)].

Special Notice #82: Update on possible X-ray transient/Nova [V598 Pup]

November 19, 2007: Further to AAVSO Special Notice #81, precise coordinates for the optical counterpart of the new X-ray source XMMSL1 J070542.7-381442 [V598 Pup] (Read et al., ATEL 1282) have been determined. The (J2000) coordinates are

RA 07:05:42.51 (+/- 0.05 arcsec) , Dec -38:14:39.3 (+/- 0.08 arcsec)

Coordinates were determined by A. Henden using V-band images supplied by S. Dvorak.

This object has now been entered into the AAVSO Variable Star Index (VSX) as: VSX J070542.5-381439

AAVSO Special Notice #81: Possible Nova/X-ray Transient [V598 Pup]

November 18, 2007: Read et al. (ATEL #1282) report the discovery by XMM-Newton of a very bright new transient, XMMSL1 J070542.7-381442 [Nova Pup 2007 = V598 Pup], located at

07:05:42.7 -38:14:42 J2000

Special Notice #405: Request for Monitoring of V4641 Sgr

August 4, 2015:  Dr. Gregory Sivakoff (U. of Alberta) has requested optical monitoring of the galactic microquasar V4641 Sgr beginning immediately, and continuing for the next 120 days, or until it is no longer observable from your location.

Alert Notice 520: X-ray nova and LMXB V404 Cyg in rare outburst

Campaign extended until further notice: As V404 Cyg's behavior following outbursts is clearly unpredictable, AAVSO observers are asked to continue obtaining multicolor photometry as well as visual observations. - April 2017

June 18, 2015: V404 Cyg, an X-ray nova and a low mass X-ray binary (LMXB) with black hole component, is undergoing its first reported X-ray and optical outburst since 1989. Large scale, rapid variations are being reported in wavelengths from X-ray to radio by professional and amateur astronomers worldwide.

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