The lightcurve of nova cygni 1975 (V 1500 Cyg) from the outburst to July 1977

Abstract

On the basis of photoelectric observations performed at the Teramo Observatory, the V lightcurve of Nova Cygni 1975 from August 1975 to July 1977 is given. Since three days after maximum thereafter, the decline pursued smoothly according the law V = 2.5 + 3.9 lg t, and 680 days after maximum the star had weakened by 12.5 mag. The well-known shortperiod light variation, which at the time of the early decline showed an amplitude smaller than 0.2 mag in V light, on December 13, 1976, displayed an amplitude as high as 0.5 mag. Table I, have been utilized; owing to the well known strong discordance generally found between the magnitudes obtained for a nova in the nebular stage by means of equipments differing even slightly in colour response, from September 5, 1975, thereafter only the Teramo observations have been considered. The equipment, an E M 1 9502 photomultiplier with 2-mm Schott GG14 + GG13 filter combination, is the same employed for the already published observations of the nova (ROSINO and TEMPESTI 1977) and the same comparison star, BD +48"3340 with assumed V magnitude 84143, was used throughout for the new observations here presented in Tables I and 2 .

A Prediction Formula of Supersoft X-Ray Phase of Classical Novae

“…Thus, we confirm that the brightnesses of the two novae are the same within an uncertainty of ±0.2 mag. This Ennis et al (1977), Gallagher & Ney (1976), and Kawara et al (1976); y and V data of V1500 Cyg are from Lockwood & Millis (1976) and Tempesti (1979). good agreement supports our assumption that two novae have the same brightness during their overlapping period if the two novae have a similar timescale as shown in Figure 7.…”

Light-Curve Analysis of Neon Novae

“…Then, we have relations between the light curves of QUVul, V1974Cyg, PWVul, and Figure 1 against that of V1500Cyg. In Figure 1, the V data for V1500Cyg are taken from Lockwood & Millis (1976) and Tempesti (1979) and the UBV data are from Pfau (1976), Arkhipova & Zaitseva (1976), Duerbeck & Wolf (1977), and Contadakis (1980). The optical V data for GKPer are the same as those in Figure 2 …”

The UBV Color Evolution of Classical Novae. III. Time-stretched Color–Magnitude Diagram of Novae in Outburst

“…• 75, 0. • 00) The BV data of V1500 Cyg are taken from Williamon (1977), Tempesti (1979), Pfau (1976), and Arkhipova & Zaitseva (1976).…”