A Galactic O2 If*/WN6 star possibly ejected from its birthplace in NGC3603

TL;DR

This paper reports the discovery of a rare, massive O2 If*/WN6 star, WR42e, located near NGC3603, with detailed analysis suggesting it may have been ejected from its birthplace and has an initial mass over 100 solar masses.

Contribution

The paper presents the identification and characterization of a new Galactic O2 If*/WN6 star, including its potential ejection from NGC3603 and estimates of its luminosity and mass, which is novel in this context.

Findings

Discovery of star WR42e near NGC3603

Estimated luminosity of about 3.2 million times the Sun's luminosity

Initial mass possibly exceeds 100 solar masses

Abstract

In this work I report the discovery of a new Galactic O2 If*/WN6 star, a rare member of the extremely massive hydrogen core-burning group of stars that due its high intrinsic luminosity (close to the Eddington limit), possess an emission-line spectrum at the beginning of their main-sequence evolution, mimicking the spectral appearance of classical WR stars. The new star is named WR42e and is found in isolation at 2.7 arcmin (about 6 pc) from the core of the star-burst cluster NGC3603. From the computed E(B-V) color excess and observed visual magnitude it was possible to estimate its absolute visual magnitude as MV =-6.3 mag, which is a value similar to those obtained by other researchers for stars of similar spectral type both, in the Galaxy and in the Large Magellanic Cloud. Considering the derived absolute visual magnitude, we computed a bolometric stellar luminosity of about 3.2x106 Lsun. Finally, the mass of the new O2If*/WN6 star was estimated by comparing its observed magnitudes and colors with those of other probable NGC3603 cluster members, founding that the WR42e initial mass possibly exceeds 100 Msun.