.2 Mass Point Source Database And Symbiotic Stars Near-infrared Classification And Evolution

This thesis includes two parts.The first part is the establishment and use of the 2MASS near infrared point sources catalog database. This point source catalog is a huge astronomical catalog containing over 400 million sources with 60 detailed parameters. In order to use the catalog more conveniently, we established a database and its query system for 2MASS infrared survey point sources catalog on local area network base on Linux operation system. Our query system can give us more information than we can get from the 2MASS website or CDS query system. Statistics and studies can be done for the given sky areas or objects by using this system, since we can query the needful information by restricting the coordinate, magnitude or color index with the given ranges.The second part is our study on the infrared classification and evolution of symbiotic stars. Now the infrared classification of symbiotic stars is based on the dust emission features in the near infrared waveband, two types of symbiotic stars are obvious two parts on the J-K, H-K color-color diagram. At first, we represented this classification using the 2MASS J, H, K magnitudes of the samples in the latest catalog of symbiotic stars, then studied its character on the IRAS far infrared [12]-[25], [25]-[60] color-color diagram. We found that the classification in near infrared also is valid in far infrared. The location of different types of symbiotic stars in far infrared color-color diagram show a kind of evolutional track. The analysis of the IRAS low resolution spectrums of our samples also implied the existence of this evolutional track. Moreover, we classified three symbiotic stars unclassified before and re-classified one.