V4743 Sagittarii
Nova that appeared in 2002
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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, making it faintly visible to the naked eye, 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]
| |
| 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]