The influence of massive stars in the interstellar medium of IC 1613: The supernova remnant S8 and the nebula S3 associated with a WO star

We present a detailed kinematic analysis of two selected nebulae in the Loc al Group irregular galaxy IC 1613. The nebulae are S8, the only known super nova remnant in this galaxy, and S3, a Wolf-Rayet nebula associated with th e only WO star in this galaxy. For S8 we have obtained and analyzed its rad ial velocity field, where we found complex profiles that can be fitted by s everal velocity components. These profiles also show the presence of high-v elocity, low-density gas. From this we have obtained the expansion velocity , estimated the preshock density, and calculated the basic kinematic parame ters of this supernova remnant (SNR). We suggest that in S8 we are seeing a n SNR partially hidden by dust. This suggestion comes from the fact that th e SNR is located between two superbubbles where a ridge of obscured materia l reveals the existence of dust. Moreover, we show that this hypothesis pre vails when arguments based on energy are taken into account. In the case of S3 this nebula shows bipolar structure. By using its kinematics, we have a nalyzed its two lobes and its "waist," II as well as its relation with the nearest superbubbles. For the first time we are able to see that the northw estern lobe is closed, showing a cloverleaf shape. This fact allows us to o btain a better quantitative knowledge of the nebula as a whole. Furthermore , we found evidence of expansion in the northwestern lobe. In the light of our results, we can state that these nebulae are the product of very massiv e stellar evolution. The influence these stars still have in shaping their surrounding gas is surprising and so is the energy liberated to the interst ellar medium of this galaxy.