The search for the origin of the Local Bubble redivivus

ABSTRACT We present anew unbiasedsearchand analysisofall B starsin the solarneighbourhood(within a volume of 400 pc diameter) using the Arivel data base to track down theremains of the OB associations, which hosted the supernovae responsible for the LocalBubble in the interstellar gas. We find after careful dereddening and by comparisonwith theoretical isochrones, that besides the Upper Scorpius the Upper CentaurusLupus and Lower Centaurus Crux subgroups are the youngest stellar associations inthe solar neighbourhood with ages of 20 to 30 Myr, in agreement with previous work.In search for the “smoking gun” of the origin of the Local Bubble, we have traced thepaths of the associations back into the past and found that they entered the presentbubble region 10 to 15 Myr ago. We argue that the Local Bubble began to form thenand estimate that 14 to 20 supernovae have gone off since. It is shown that the impliedenergy input is sufficient to excavate a bubble of the presently observed size.Key words: solar neighbourhood - open clusters and associations: individual:ScoOB2 - ISM: individual: local bubble - Local ISM