# Optical spectroscopic and polarization properties of 2011 outburst of the recurrent nova T Pyxidis

## TL;DR

This study analyzes the spectroscopic and polarization evolution of the 2011 outburst of recurrent nova T Pyxidis, modeling ejecta structure and dynamics to understand its physical conditions and geometry.

## Contribution

It provides detailed spectroscopic, polarimetric, and modeling analysis of T Pyxidis's 2011 outburst, revealing ejecta geometry and physical parameters.

## Key findings

- Spectral evolution similar to previous outbursts
- Ejected mass estimated at 7.03 x 10^-6 M_sun
- Ejecta has bipolar conical structure with low inclination

## Abstract

We study the spectroscopic and ionized structural evolution of T Pyx during its 2011 outburst, and also study the variation in degree of polarization during its early phase. Optical spectroscopic data of this system obtained from day 1.28--2415.62 since discovery, and optical, broadband imaging polarimetric observations obtained from day 1.36--29.33 during the early phases of the outburst are used in the study. The physical conditions and the geometry of the ionized structure of the nova ejecta has been modelled for a few epochs using the photo-ionization code, CLOUDY in 1D and pyCloudy in 3D. The spectral evolution of the nova ejecta during its 2011 outburst is similar to that of the previous outbursts. The variation in the line profiles is seen very clearly in the early stages due to good coverage during this period. The line profiles vary from P-Cygni (narrower, deeper and sharper) to emission profiles which are broader and structured, which later become narrower and sharper in the late post-outburst phase. The average ejected mass is estimated to be $7.03\, \times\, 10^{-6}\, M_{\odot}$. The ionized structure of the ejecta is found to be a bipolar conical structure with equatorial rings, with a low inclination angle of $14.75^\circ\, \pm\, 0.65^\circ$.