Light curve analysis of classical novae: Free-free emission vs photospheric emission

Izumi Hachisu, Mariko Kato

Research output: Contribution to journalArticle

Abstract

We analyzed light curves of relatively slower novae, based on an optically thick wind theory of nova outbursts. In slower novae, we must take into account photospheric emission as well as free-free emission because their wind mass loss rates are smaller and the brightness of free-free emission is as faint as photospheric emission. We calculated model light curves of free-free plus photospheric emission for various WD masses and various chemical compositions of the envelopes, and fitted them reasonably with observational data of optical, near-infrared (NIR), and UV bands. From light curve fittings, we estimated their absolute magnitudes, distances, and WD masses. In the fast novae V1668 Cyg and V1974 Cyg, free-free emission dominates the spectrum in the optical and NIR regions, so the optical and NIR light curves follow the universal decline law. In slower novae PW Vul and V705 Cas, free-free emission still dominates the spectrum in the optical and NIR bands but photospheric emission contributes significantly to the spectrum in the later phase. In very slow novae such as RR Pic and V723 Cas, photospheric emission dominates the spectrum rather than free-free emission. These photospheric emission effect makes a deviation from the universal decline law and therefore a systematic deviation from the proposed maximum magnitude vs rate of decline (MMRD) relation.

Original languageEnglish
Article number053
JournalProceedings of Science
VolumePart F133206
Publication statusPublished - 2015 Jan 1

ASJC Scopus subject areas

  • General

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