V1494 Aql: Eclipsing Fast Nova with an Unusual Orbital Light Curve

Abstract

We present time-resolved photometry of V1494 Aql (Nova Aql 1999 No. 2) between 2001 November and 2003 June. The object is confirmed to be an eclipsing nova with a period of 0.1346138(2) d. The eclipses were present in all observed epochs. The orbital light curve shows a rather unusual profile, consisting of a bump-like feature at phase 0.6-0.7 and a dip-like feature at phase 0.2-0.4. These features were probably persistently present in all available observations between 2001 and 2003. A period analysis outside the eclipses has confirmed that these variations have a period common to the orbital period, and are unlikely interpreted as superhumps. We suspect that structure (probably in the accretion disk) fixed in the binary rotational frame is somehow responsible for this feature.

On the close optical companion of V1494 Aql: Problems with light curve modelling

“…On one hand, both Barsukova & Goranskii (2003) and Pavlenko et al (2003) mentioned the presence of the companion but they did not go beyond that. On the other hand, despite using unfiltered observations heavily influenced by the red companion, Kato et al (2003) did not even mention the problem. Our conclusion is that one has to be very careful when analysing observations of V1494 Aql and reliable modelling requires accurate correction for the light of the companion.…”

“…1 that the nova is fainter than the companion both in R and I (by chance, the analysed images were taken very close to the primary eclipse; the ephemeris in Kato et al 2003 gives φ(R) = 0.035 and φ(I) = 0.002). This means that the estimated contribution of the companion is much larger than quoted in Barsukova & Goranskii (2003) …”

“…Shortly after discovery in December 1999 (Pereira et al 1999), it peaked at m vis = 4 mag, followed by rapid dimming (t 3 = 16 d, Kiss & Thomson 2000). The light curve showed a classical transition phase with quasiperiodic oscillations (see an updated light curve in Kato et al 2003). Optical spectroscopy (Kiss & Thomson 2000;Anupama et al 2001;Arkhipova et al 2002;Iijama & Esenoglu 2003) showed that the nova belonged to the "Fe II" class of Williams (1992) with early expansion velocities up to 2000 km s −1 .…”

Spectroscopic monitoring of the transition phase in nova V4745 Sgr

“…It is possible that this difference is due to the inclination difference between the two systems. V1494 Aql is an eclipsing binary which shows fadings with deep minima (Kato et al 2004a, and references therein), so that the inclination of the binary system should be close to 90…”

The Detection of a 3.5 hr Period in the Classical Nova Velorum 1999 (V382 Vel) and the Long-Term Behavior of the Nova Light Curve

“…In general, eclipses or occultation effects are detected from novae in outburst and in quiescence (Leibowitz et al 1992;Kato et al 2004;Shafter et al 1993, Woudt & Warner 2001, 2003. For example, V838 Her (N Her 1991) shows variable eclipse depth that lasts from 2 to 3 hours, whose depth varies between 0.1 and 0.4 magnitues in about 4 month (Leibowitz et al 1992).…”