A massive runaway star from 30 Doradus

TL;DR

This study characterizes 30 Dor 016, a massive O2 star in the Large Magellanic Cloud, revealing its extremely fast stellar wind and its likely origin as a runaway star ejected from 30 Doradus.

Contribution

First UV and multi-epoch optical spectroscopy of 30 Dor 016, identifying its high-velocity stellar wind and confirming its status as a runaway star.

Findings

Stellar wind terminal velocity of 3450 km/s.

No evidence of a massive companion within 1 year orbital period.

Star likely ejected from 30 Doradus, traveling 120 pc as a runaway.

Abstract

We present the first ultraviolet (UV) and multi-epoch optical spectroscopy of 30 Dor 016, a massive O2-type star on the periphery of 30 Doradus in the Large Magellanic Cloud. The UV data were obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope as part of the Servicing Mission Observatory Verification program after Servicing Mission 4, and reveal #016 to have one of the fastest stellar winds known. From analysis of the CIV 1548-51 doublet we find a terminal velocity, v_infty=3450 +/- 50km/s. Optical spectroscopy is from the VLT-FLAMES Tarantula Survey, from which we rule out a massive companion (with 2d<P<1yr) to a confidence of 98%. The radial velocity of #016 is offset from the systemic value by -85km/s, suggesting that the star has traveled the 120pc from the core of 30 Doradus as a runaway, ejected via dynamical interactions.