Bright nova V462 Lup Has Orbital Period of 1.797 Hours, at the Bottom of the Period Gap
ATel #17240; Bradley E. Schaefer (Louisiana State University)
on 23 Jun 2025; 02:54 UT
Credential Certification: Bradley E. Schaefer (schaefer@lsu.edu)
Referred to by ATel #: 17281
The nova V462 Lup (ATel #17228, ATel #17237) has reached a peak of V=5.5 on 2025-06-20, after a smooth observed rise taking more than 6 days. This is an ordinary Fe II nova, while the pre-eruption counterpart appears as an isolated blue star for which Gaia gives G=18.34.
I have extracted the TESS light curves for Sectors 11, 38 and 65, centered on 2019.35, 2021.35, and 2023.35. All three Sectors reveal only one significant peak in the Fourier transforms, and the periodicity is identical and highly significant in all three Sectors individually. The periodicity is coherent across the data from 2019.35 to 2023.35. The folded light curve appears as a simple sinewave. The epoch for minimum flux is BJD 2459343.53317. With a chi-square fit to all 15053 fluxes from the three Sectors, the period is 0.07488825 +- 0.00000016 days. The possibility of a 2-year aliasing allows for the period to differ from this by N*0.001362 days, for integer N values of -2, -1, 0, +1, or +2. This period is 1.797 hours.
This periodicity is coherent and stable over 4.0 years, so it must be the orbital period. This orbital period is inside and near the bottom of the nova period gap (Schaefer 2022, MNRAS, 517, 3640).
