The $UBV$ Color Evolution of Classical Novae. IV. Time-Stretched $(U-B)_0$-$(M_B-2.5\log f_{\rm s})$ and $(V-I)_0$-$(M_I-2.5\log f_{\rm s})$ Color-Magnitude Diagrams of Novae in Outburst

Izumi Hachisu; Mariko Kato

doi:10.3847/1538-4365/abd31e

paper

The $U B V$ Color Evolution of Classical Novae. IV. Time-Stretched $(U - B)_{0}$ - $(M_{B} - 2.5 lo g f_{s})$ and $(V - I)_{0}$ - $(M_{I} - 2.5 lo g f_{s})$ Color-Magnitude Diagrams of Novae in Outburst

arXiv:2012.06100 · doi:10.3847/1538-4365/abd31e

Abstract

Light curves and color evolutions of two classical novae can be largely overlapped if we properly squeeze or stretch the timescale of a target nova against that of a template nova by $t^{'} = t / f_{s}$ . Then the brightness of the target nova is related to the brightness of the template nova by $(M [t])_{template} = (M [t / f_{s}] - 2.5 lo g f_{s})_{target}$ , where $M [t]$ is the absolute magnitude and a function of time $t$ , and $f_{s}$ is the ratio of timescales between the target and template novae. In the previous papers of this series, we show that many novae broadly overlap in the time-stretched $(B - V)_{0}$ - $(M_{V} - 2.5 lo g f_{s})$ color-magnitude diagram. In the present paper, we propose two other $(U - B)_{0}$ - $(M_{B} - 2.5 lo g f_{s})$ and $(V - I)_{0}$ - $(M_{I} - 2.5 lo g f_{s})$ diagrams, and show that their tracks overlap for 16 novae and for 52 novae, respectively. Here, $(U - B)_{0}$ , $(B - V)_{0}$ , and $(V - I)_{0}$ are the intrinsic $U - B$ , $B - V$ , and $V - I$ colors and not changed by the time-stretch, and $M_{B}$ , $M_{V}$ , and $M_{I}$ are the absolute $B$ , $V$ , and $I$ magnitudes. Using these properties, we considerably refine the previous estimates of their distance and reddening. The obtained distances are in reasonable agreement with those of {\it Gaia} Data Release 2 catalogue.

211 pages, 178 figures, typos corrected, published in ApJS, 253, 27 (2021). arXiv admin note: text overlap with arXiv:1905.10655

The $U B V$ Color Evolution of Classical Novae. IV. Time-Stretched $(U - B)_{0}$ - $(M_{B} - 2.5 lo g f_{s})$ and $(V - I)_{0}$ - $(M_{I} - 2.5 lo g f_{s})$ Color-Magnitude Diagrams of Novae in Outburst

Abstract

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The UBV Color Evolution of Classical Novae. IV. Time-Stretched (U−B)0​-(MB​−2.5logfs​) and (V−I)0​-(MI​−2.5logfs​) Color-Magnitude Diagrams of Novae in Outburst

Abstract

References in corpus (18)

Cited by in corpus (5)

The $U B V$ Color Evolution of Classical Novae. IV. Time-Stretched $(U - B)_{0}$ - $(M_{B} - 2.5 lo g f_{s})$ and $(V - I)_{0}$ - $(M_{I} - 2.5 lo g f_{s})$ Color-Magnitude Diagrams of Novae in Outburst