Supplementary Materials

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

Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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  • Materials and Methods
  • Supplementary Text
  • Figs. S1 to S7
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Correction (2 July 2015): A bug in a software script in the calculation of RL from Eq. 4 has been corrected. The new values were compared to realistic pure He-star models calculated as described in (8). Fig. S4 has been updated and shows consistent solutions for He-star masses from ~0.3 to 0.35 M☉ and WD masses >1.0 M☉. The orbital period is constrained to ~10 to 15 min.

Both the He-star and the Roche lobe radii are considerably smaller than the original calculations. This changes the predicted rotational velocity of the He star at the moment of ejection to ~350 km s-1. During evolution on the extreme horizontal branch, the radius of the subdwarf O increases by a higher factor of ~2.8 after the ejection. Assuming conservation of angular momentum, the rotational velocity is now predicted to be ~120 km s−1, matching the measured vrot sin i = 115 ± 8 km s−1. No additional mechanisms for the loss of angular momentum need to be invoked, and our proposed scenario is now even more consistent with the observations.
The original version is accessible here.