Velocity and spectrum of the supernova remnant 30 Dor B

We present an analysis of the spectrum of the supernova remnant 30 Doradus B (N175 B), within the 30 Dor B H II region in the Large Magellanic Cloud. Our data yield a velocity dispersion estimate (≳ 630 km s⁻¹) and the size of the remnant ($$r_\text {shock} \leqslant 30 \enspace \text {arcsec}\equiv7\enspace\text {pc}$$). The remnant properties suggest that the supernova outburst energy was E₀, such that E₀/n_H ≲ 3 × 10⁵⁰ erg cm³. Since n_H ∼ 40 cm⁻³ in the surrounding medium, the outburst energy E₀ ≲ 2 × 10⁵² erg. A Type II classification accords with its association with Population I. In its radio and X-ray properties 30 Dor B resembles the Crab Nebula, but continuum emission from 30 Dor B correlates with Hα emission and is probably from two-photon hydrogen recombination.