2025/06/05 by Mariko Kato, Izumi Hachisu, Kato, Mariko +3 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #FOS: Physical sciences #Gamma-ray bursts and supernovae #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2506.04615
openalex publication_date 2025/06/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
V1674 Her is one of the fastest novae, of which the very early phase is well observed including optical rise to the peak over 10 magnitudes. We present a full theoretical light curve model of V1674 Her. Our 1.35~M_\odot white dwarf (WD) model with the mass accretion rate of 1× 10-11~M_\odot yr-1 explains overall properties including a very fast rise and decay of the optical V light curve. The WD photosphere expands up to 21 ~R_\odot, thus, a 0.26 ~M_\odot companion star orbiting the WD every 3.67 hours, is engulfed 2.7 hours after the onset of thermonuclear runaway, and appears 5.3 days after that. The duration of X-ray flash is only 0.96 hours. The evolution of the expanding envelope and temporal change of the photospheric radius are very consistent with observed optical and X-ray modulations with the orbital and spin (501 s) periods. We confirmed that the decay phase of nova light curve is well approximated by a sequence of steady-state envelope solutions. Using time-stretching method of nova light curves, we obtain the V band distance modulus of (m-M)V= 16.3± 0.2, and determine the distance to be d=8.9± 1 kpc for the interstellar extinction of E(B-V)= 0.5 ± 0.05.