2000A&A...363..755K

We present the results of optical, far-infrared and radio observations of the small, non-star forming dark cloud Khavtassi 15, located in the Upper Cepheus-Cassiopeia region. We derive an average extinction of A_V=1.6mag and a distance of 250±25pc from Digitized Sky Survey data and star counts using objective prism spectroscopy. A fully computerized algorithm was used for non-biased analysis of starcount data. A kinetic temperature of 7K and a peak number density of n(H₂)=5.9x10³cm^–3 were estimated from multiisotopic, multilevel CO measurements. CO measurements also revealed three main condensations inside the cloud. Kh 15 has a total gas mass of 34M_☉ and it is most probably part of a shell seen as a FIR loop called GIRL 126+10. We investigated the correlation among optical extinction, radio and FIR emission and masses derived for the dust and gas inside the cloud core. Stability analysis has shown, that object Kh 15 is not far from gravitational virial equilibrium, and may be fully stabilized by the external pressure. In addition to Kh 15, the starcounts also indicate the presence of an extended nearby extinction layer at d ≤150pc which we consider as the wall of the Local Bubble (LB) towards the Upper Cepheus-Cassiopeia. Distances of the dark clouds LDN 1308, LDN 1333 and Khavtassi 19 are also estimated.