1. Max Planck Institut für extraterrestrische Physik, Postfach 1603, D-85740 Garching, Germany
2. Astrophysics Division, ESTEC, 2200 AG Noordwijk, The Netherlands
3. SRON-Utrecht, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
4. University of New Hampshire, Institute for Studies of Earth, Oceans and Space, Durham, New Hampshire 03284, USA

Correspondence to: A. F. Iyudin¹ Correspondence and requests for materials should be addressed to A.F.I.
(e-mail: Email: ani@mpe-garching.mpg.de).

Abstract

Nearly 400 years have passed since a supernova was last observed directly in the Milky Way (by Kepler, in 1604). Numerous Galactic supernovae are expected to have occurred since then¹, but only one (Cassiopeia A) may have been seen². The historical record of supernovae is therefore incomplete, as demonstrated by the spatial distribution of young supernova remnants³. The discovery⁴,⁵ of -ray emission from the decay of ⁴⁴Ti nuclei associated with Cassiopeia A, the youngest known remnant, has revealed a new way to search for the remnants of other relatively recent supernovae (less than 1,000 years old). Here we report the discovery of ⁴⁴Ti line emission from a previously unknown young supernova remnant, in the direction of the Vela remnant. We estimate a distance of 200 parsecs and an age of 680 years for the remnant, making it the closest young remnant to the Earth. Why it was not recorded historically remains unknown.