Wind parameters of the new LBV in NGC1156

TL;DR

This paper models the spectrum of a newly discovered luminous blue variable in NGC 1156, providing key stellar parameters using advanced atmosphere modeling techniques.

Contribution

It presents the first detailed spectrum modeling of the LBV in NGC 1156 using non-LTE atmosphere models, deriving its fundamental stellar parameters.

Findings

Luminosity approximately 1.6 million solar luminosities

Effective temperature around 7,900 K

Mass-loss rate about 8.2 x 10^{-4} solar masses per year

Abstract

In this work we present the spectrum modeling results for the newly discovered luminous blue variable (LBV) in the NGC 1156 galaxy. Extended atmosphere models were calculated using the non-LTE code CMFGEN. We have obtained the luminosity of the discovered LBV $L\simeq (1.6\pm0.2) \times 10^{6} L_{\odot}$, effective temperature $T_{\text{eff}}=7.9\pm0.4$ kK and mass-loss rate $\dot{M}f^{-0.5}= (8.2\pm1.0) \times 10^{-4} M_{\odot}\text{yr}^{-1}$. The hydrogen abundance in the wind is $\approx20\,$% for the metallicity $Z=0.5 Z_{\odot}$ of the host galaxy.