We present the database of maser sources in H2 O, OH and Si O lines that can be used to identify and study variable stars at evolved stages. Detecting the maser emission in H2 O, OH and Si O molecules toward infrared-...We present the database of maser sources in H2 O, OH and Si O lines that can be used to identify and study variable stars at evolved stages. Detecting the maser emission in H2 O, OH and Si O molecules toward infrared-excess objects is one of the methods for identifing long-period variables(LPVs, including miras and semiregulars), because these stars exhibit maser activity in their circumstellar shells. Our sample contains 1803 known LPV objects. Forty-six percent of these stars(832 objects) manifest maser emission in the line of at least one molecule: H2 O, OH or Si O. We use the database of circumstellar masers in order to search for LPVs which are not included in the General Catalogue of Variable Stars(GCVS). Our database contains 4806 objects(3866 objects without associations in GCVS) with maser detection in at least one molecule. Therefore it is possible to use the database in order to locate and study the large sample of LPV stars. The database can be accessed at http://maserdb.net.展开更多
We report variation of K-band infrared(IR) emission in the vicinity of the G025.65+1.05 water and methanol maser source. New observational data were obtained with the 2.5 m telescope at the Caucasian Mountain Observat...We report variation of K-band infrared(IR) emission in the vicinity of the G025.65+1.05 water and methanol maser source. New observational data were obtained with the 2.5 m telescope at the Caucasian Mountain Observatory(CMO) of Moscow State University on 2017–09–21 during a strong water maser flare. We found that the IR source situated close to the maser position had decreased brightness in comparison to archive data. This source is associated with a massive young stellar object(MYSO) corresponding to the compact IR source IRAS 18316–0602(RAFGL 7009 S). A similar decrease in K-brightness of the IR source close to the maser position was observed in March 2011 when the water maser experienced a period of increased activity. The dips in MYSO brightness can be related to the maser flare phases. Maser flares that are concurrent with dips in the IR emission can be explained if the lower IR radiation field enables a more efficient sink for the pumping cycle by allowing IR photons to escape the maser region.展开更多
The chemical classification of IRAS 17515-2407 has been debated for a longtime. Up to now there are two contenders, oxygen-rich or carbon-rich. We believe that IRAS17515-2407 is an oxygen-rich source: because (ⅰ) it ...The chemical classification of IRAS 17515-2407 has been debated for a longtime. Up to now there are two contenders, oxygen-rich or carbon-rich. We believe that IRAS17515-2407 is an oxygen-rich source: because (ⅰ) it shows the silicate self-absorbed emission; (ⅱ)in the near infrared-IRAS diagram it is located in the oxygen-rich object region and (ⅲ)particularly, it has detected SiO maser emission.展开更多
With the objective of studying the relationships between high-velocity gas and water maser emissions the results of a search from 95 IRAS sources for high-velocity gas associated with star forming molecular clouds are...With the objective of studying the relationships between high-velocity gas and water maser emissions the results of a search from 95 IRAS sources for high-velocity gas associated with star forming molecular clouds are reported. 21 sources have been identified as molecular outflow candidates.展开更多
基金funded by the Russian Foundationfor Basic Research through research project 18-32-00605supported by Russian Science Foundation grant18-12-00193supported by Act 211 of theGovernment of the Russian Federation, agreement No.02.A03.21.0006
文摘We present the database of maser sources in H2 O, OH and Si O lines that can be used to identify and study variable stars at evolved stages. Detecting the maser emission in H2 O, OH and Si O molecules toward infrared-excess objects is one of the methods for identifing long-period variables(LPVs, including miras and semiregulars), because these stars exhibit maser activity in their circumstellar shells. Our sample contains 1803 known LPV objects. Forty-six percent of these stars(832 objects) manifest maser emission in the line of at least one molecule: H2 O, OH or Si O. We use the database of circumstellar masers in order to search for LPVs which are not included in the General Catalogue of Variable Stars(GCVS). Our database contains 4806 objects(3866 objects without associations in GCVS) with maser detection in at least one molecule. Therefore it is possible to use the database in order to locate and study the large sample of LPV stars. The database can be accessed at http://maserdb.net.
基金supported by the Russian ScienceFoundation (Grant 18-12-00193)supported by Russian Foundation for Basic Research(Grant 18-32-00314)
文摘We report variation of K-band infrared(IR) emission in the vicinity of the G025.65+1.05 water and methanol maser source. New observational data were obtained with the 2.5 m telescope at the Caucasian Mountain Observatory(CMO) of Moscow State University on 2017–09–21 during a strong water maser flare. We found that the IR source situated close to the maser position had decreased brightness in comparison to archive data. This source is associated with a massive young stellar object(MYSO) corresponding to the compact IR source IRAS 18316–0602(RAFGL 7009 S). A similar decrease in K-brightness of the IR source close to the maser position was observed in March 2011 when the water maser experienced a period of increased activity. The dips in MYSO brightness can be related to the maser flare phases. Maser flares that are concurrent with dips in the IR emission can be explained if the lower IR radiation field enables a more efficient sink for the pumping cycle by allowing IR photons to escape the maser region.
基金Supported by the National Natural Science Foundation of China
文摘The chemical classification of IRAS 17515-2407 has been debated for a longtime. Up to now there are two contenders, oxygen-rich or carbon-rich. We believe that IRAS17515-2407 is an oxygen-rich source: because (ⅰ) it shows the silicate self-absorbed emission; (ⅱ)in the near infrared-IRAS diagram it is located in the oxygen-rich object region and (ⅲ)particularly, it has detected SiO maser emission.
文摘With the objective of studying the relationships between high-velocity gas and water maser emissions the results of a search from 95 IRAS sources for high-velocity gas associated with star forming molecular clouds are reported. 21 sources have been identified as molecular outflow candidates.
