V500 Aquilae

Lore & Background

V500 Aquilae was discovered by Cuno Hoffmeister on photographic plates taken at Sonneberg Observatory on 5 September 1943, when it had a photographic magnitude of 12. Its peak brightness occurred between 13 April 1943, when it was fainter than photographic magnitude 13.5, and 2 May 1943, when its photographic magnitude was 6.55 (6.1 visual magnitude). The nova's brightness dropped by 3 magnitudes from its peak in 42 days, classifying it as a fast nova.

Like all novae, V500 Aquilae is a binary star system with a donor star orbiting a white dwarf. The stars are so close that matter transfers from the donor to the white dwarf. Because the separation is comparable to the donor star's radius, novae are often eclipsing binaries, and V500 Aquilae does show eclipses. These eclipses, first seen in 1994 at the European Southern Observatory, have a depth of about 0.4 magnitudes, and the orbital period is 3.485±0.02 hours.

In 1984, a small nova remnant surrounding V500 Aquilae, with a radius of 2.0 arc seconds and expanding at 1380 km/s, was discovered using the Hale Telescope. The expansion of that remnant has been used to derive a distance estimate of 4900 parsecs.

Reader's Guide

V500 Aquilae is significant as a well-documented fast nova from 1943, providing key data on nova light curves and binary system properties. Its discovery by Cuno Hoffmeister at Sonneberg Observatory on 5 September 1943, and its peak brightness between 13 April and 2 May 1943, establish a precise timeline for its outburst. The measured drop of 3 magnitudes in 42 days defines its classification as a fast nova, contributing to the understanding of nova evolution rates.

The system's eclipsing binary nature, with eclipses first observed in 1994 at the European Southern Observatory, offers direct measurements of the orbital period (3.485±0.02 hours) and eclipse depth (0.4 magnitudes). This makes V500 Aquilae a valuable object for studying mass transfer and binary dynamics in cataclysmic variables.

Additionally, the discovery in 1984 of a small nova remnant (radius 2.0 arc seconds) expanding at 1380 km/s, using the Hale Telescope, allowed a distance estimate of 4900 parsecs. This remnant provides constraints on the nova's ejecta and its interaction with the interstellar medium, furthering knowledge of nova shell evolution.

Did You Know?

• Its peak photographic magnitude was 6.55, with a visual magnitude of 6.1.
• The nova's brightness dropped by 3 magnitudes in 42 days, making it a fast nova.
• Eclipses in the system were first seen in 1994 at the European Southern Observatory, with an orbital period of 3.485±0.02 hours.