The fastest unbound star in our Galaxy ejected by a thermonuclear supernova

S. Geier*, F. Fürst, E. Ziegerer, T. Kupfer, U. Heber, A. Irrgang, B. Wang, Z. Liu, Z. Han, B. Sesar, D. Levitan, R. Kotak, E. Magnier, K. Smith, W. S. Burgett, K. Chambers, H. Flewelling, N. Kaiser, R. Wainscoat, C. Waters

*Corresponding author for this work

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Abstract

Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ∼1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova.

Original languageEnglish
Pages (from-to)1126-1128
Number of pages3
JournalScience
Volume347
Issue number6226
DOIs
Publication statusPublished - 06 Mar 2015

ASJC Scopus subject areas

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    Geier, S., Fürst, F., Ziegerer, E., Kupfer, T., Heber, U., Irrgang, A., Wang, B., Liu, Z., Han, Z., Sesar, B., Levitan, D., Kotak, R., Magnier, E., Smith, K., Burgett, W. S., Chambers, K., Flewelling, H., Kaiser, N., Wainscoat, R., & Waters, C. (2015). The fastest unbound star in our Galaxy ejected by a thermonuclear supernova. Science, 347(6226), 1126-1128. https://doi.org/10.1126/science.1259063