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Star Formation in the Cepheus Flare Molecular Clouds. I. Distance Determination and the Young Stellar Object Candidates
Results of an objective prism Schmidt survey are combined with IRASsurvey data in order to assess the star-forming activity in the CepheusFlare, a nearby giant molecular cloud complex at ~+15 deg above theGalactic equator. The distribution of absorbing matter along the line ofsight was also studied. The Wolf diagrams, displaying the cumulativedistribution of field star distance moduli, show that the interstellarmatter in this region is concentrated at three characteristic distances:200, 300, and 450 pc. The three components, though partly overlapping,can be separated along the Galactic latitude. Within the area of theCepheus Flare, distances are determined for 14 Lynds dark clouds and forsome other clouds. In order to compile a sample of young stellar object(YSO) candidates, three types of star formation signposts were searchedfor the following: 1. Prestellar cores in the IRAS 100 mu m opticaldepth image of the region, 2. Far-infrared sources representing embeddedYSOs and optically visible pre-main-sequence star candidates using IRASPoint Source Catalog, Faint Source Catalog, and calibrated IRAS detectorscans, 3. H alpha emission stars appearing on low-dispersion objectiveprism Schmidt plates as candidate pre-main-sequence stars. The IRAS 100mu m optical depth image of the region revealed 107 dense cores. Most ofthem are probably "starless" cores and, as such, potential sites offuture star formation. One hundred twenty-two IRAS point sources wereselected as probable YSOs at various evolutionary stages. An objectiveprism search for H alpha emission stars covering an area of about 150deg2 resulted in the detection of 142 H alpha emission stars. Infraredfluxes taken from the IRAS catalogs or determined from the detectorscans are listed for 95 of them. This sample is expected to consist ofmostly T Tauri stars associated with the cloud complex. Finding chartsand catalogs of the young stellar object candidates are also given.These results may serve as a basis for further dedicated studies of theregion and will be useful for comparison when star-forming activity inother cloud complexes is investigated.
| Observational studies relating to stars formation. III.
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