Deep optical study of the mixed-morphology supernova remnant G 132.7+1.3
  (HB3)
  We present optical ccd images of the large supernova remnant (SNR)
G132.7$+$1.3 (HB3) covering its full extent for the first time, in the emission
lines of H$\alpha+$[N II], [S II] and [O III], where new and known filamentary
and diffuse structures are detected. These observations are supplemented by new
low-resolution long-slit spectra and higher-resolution images in the same
emission lines. Both the flux-calibrated images and spectra confirm that the
optical emission originates from shock-heated gas since the [S II]/H$\alpha$
$>$ 0.4. Our findings are also consistent with the recently developed emission
line ratio diagnostics for distinguishing SNRs from H II regions. A
multi-wavelength comparison among our optical data and relevant observations in
radio, X-rays, $\gamma$-rays and CO bands, provided additional evidence on the
interaction of HB3 with the surrounding clouds and clarified the borders of the
SNR and the adjacent cloud. We discuss the supernova (SN) properties and
evolution that led to the current observables of HB3 and we show that the
remnant has most likely passed at the pressure driven snowplow phase. The
estimated SN energy was found to be $\left(3.7 \pm 1.5\right) \times 10^{51}$
erg and the current SNR age $\left(5.1 \pm 2.1\right) \times 10^4$ yrs. We
present an alternative scenario according to which the SNR evolved in the wind
bubble cavity excavated by the progenitor star and currently is interacting
with its density walls. We show that the overall mixed morphology properties of
HB3 can be explained if the SN resulted by a Wolf-Rayet progenitor star with
mass $\sim 34 \rm~M_{\rm\odot}$.
