V4743 Sagittarii was a bright nova in the southern constellation of Sagittarius. This event was discovered by K. Haseda and colleagues in September 2002.[1] It peaked at magnitude 5.0[7] on September 20, 2002, then declined rapidly thereafter. It reached a peak temperature of 740,000 K around April 2003 and remained at that level for at least five months, suggesting the white dwarf component has a mass of 1.1–1.2 M_☉.[8] The distance to this system is uncertain.[3] Infrared observations indicate a distance of approximately 21 kly (6.3 kpc).[4] A derivation using maximum magnitude rate of decay showed a distance of 12.7 ± 1.0 kly (3.9 ± 0.3 kpc).[8]

V4743 Sagittarii

Location of V4743 Sagittarii (circled in red)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Sagittarius
Right ascension	19h 01m 09.38s[1]
Declination	−22° 00′ 05.9″[1]
Apparent magnitude (V)	5.0 – 16.8[2]
Characteristics
Variable type	CN[3]
Astrometry
Distance	~21,000[4] ly (6,300 pc)
Details
Mass	1.22[5] M☉
Other designations
Nova Sagittarii 2002 c, V4743 Sgr, AAVSO 1855-22[6]
Database references
SIMBAD	data

Observations of the nova by the Chandra X-ray Observatory taken 180 days after the event showed an amplitude variation with a period of about 22 minutes. The X-ray output was dropping rapidly, and changed from a continuous spectrum to one showing emission lines. X-ray light curves of this system show a periodic signal with a frequency of 0.75 MHz that suggests a rapidly rotating magnetic white dwarf in an intermediate polar system.[9][8] In 2003, an optical variation of 6.74 ± 0.07 hours was observed, and was interpreted as the orbital period of the binary system.[4] A proposed beat period of ~24 minutes has been detected in the optical in between the orbital and period cycles.[3]

References