V1369 Cen high resolution panchromatic late nebular spectra in the context of a unified picture for nova ejecta

TL;DR

This study analyzes high-resolution late nebular spectra of Nova V1369 Cen to understand its ejecta properties, revealing a clumpy, ballistic expansion consistent with classical novae, and highlights unique chemical abundance features.

Contribution

It provides detailed physical and geometrical analysis of V1369 Cen's ejecta, comparing it with other novae to support a unified clumpy ejecta model and identifying unusual chemical signatures.

Findings

Ejecta are clumpy and in ballistic expansion, not wind-driven.

Ejecta mass is about 10^-4 solar masses, larger than recurrent novae.

V1369 Cen shows anomalously high N/C ratio and unusual Ne line strengths.

Abstract

Nova Cen 2013 (V1369 Cen) is the fourth bright nova observed panchromatically through high resolution UV+optical multi epoch spectroscopy. It is also the nova with the richest set of spectra (both in terms of data quality and number of epochs) thanks to its exceptional brightness. Here, we use the late nebular spectra taken between day ~250 and day ~837 after outburst to derive the physical, geometrical and kinematical properties of the nova. We compare the results with those determined for the other panchromatic studies in this series: T Pyx, V339 Del (nova Del 2013), and V959 Mon (nova Mon 2012). From this we conclude that in all these novae the ejecta geometry and phenomenology can be consistently explained by clumpy gas expelled during a single, brief ejection episode and in ballistic expansion, and not by a wind. For V1369 Cen the ejecta mass (about 1E-4 solar masses) and filling factor (0.1<=f<=0.2) are consistent with those of classical novae but larger (by at least an order of magnitude) than those of T Pyx and the recurrent novae. V1369 Cen has an anomalously high relative to solar N/C ratio that is beyond the range currently predicted for a CO nova, and the Ne emission line strengths are dissimilar to those of typical ONe or CO white dwarfs.