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Spectral evolution of the H2O maser in late-type stars
We have carried out almost simultaneous observations of H2O and SiO (J =1-0, v = 1) masers for 171 known late-type maser stars with the 34 mradio telescope at Kashima. We found a systematic change in the H2Omaser spectra related to the evolution of the stars. Typically, H2Omaser spectral profiles are singly peaked in Mira variables, but doublypeaked in IRC/AFGL objects and OH/IR stars. The expansion velocity ofH2O masers increases with decreasing IRAS color temperature. This isexplained by the shock excitation model proposed by Cooke and Elitzur(1985). The blue shifted peak in the profiles is more prominent than thered shifted peak in most of the IRC/AFGL objects and OH/IR stars. Ablocking model of the redshifted peak is introduced.
| 86 GHz SiO, v=1, J=2--> 1 survey of southern IRAS point sources. II. Detection of 74 new maser sources
The detection of 74 new southern stellar SiO, v=1, J=2->1 masersassociated with IRAS point sources is reported. 57 of these were foundin an IRAS based survey of oxygen rich stellar envelopes. The detectionrate in this survey was 45%. 17 further new maser sources were detectedduring a search for strong pointing sources for the Swedish-ESOSubmillimeter Telescope (SEST). The distribution of the IRAS lowresolution spectral (LRS) classes of all the SiO masers (this paper andliterature) peaks sharply at class 15. The distribution of the LRSclasses of the maser sources from 21 to 29 is similar to thedistribution of these classes of all the point sources in the pointsource catalogue except for class 25. Only few maser sources of thisspectral class are known. This is possibly explained by a selectioneffect.
| Observations of 43-GHz SiO masers associated with bright IRAS sources
A survey of potential SiO maser sources has been made using the Parkesradio telescope operating at 43 GHz. The candidate objects were allbright southern IRAS sources and were selected using criteria developedfor use in an earlier study. A further 29 masers were discovered in thepresent survey and, for most of these sources, data in both v = 1 and v= 2 (J = 1-0) transitions were obtained. Although many of the candidateIRAS sources have not been observed at visual wavelengths, there arepublished optical variability data for nine objects. In these cases therelationship between SiO maser emission and visual amplitude, proposedpreviously, is not violated. It is suggested that, in the main, the newmasers are associated with optically obscured Mira variables. This paperalso presents the latest 43-GHz maser polarization spectra for thenearest symbiotic binary, R Aqr, and for GL 5552, the most intensesource discovered in an earlier survey.
| Photoelectric photometry of M-type stars
UBVRI photoelectric photometry was obtained for 110 M-type starscontained in the Caltech Two-Micron Survey and the revised AFGL Catalog.Of the 110 stars, 58 have a color index (B-R) greater than or equal to 4mag. A graph is given of (V-R) versus (V-I) for the present stars.
| Classification of 831 two-micron sky survey sources south of +5 degrees.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975AJ.....80.1011H&db_key=AST
| Listes et classifications d'étoiles M, S, C, trouvées dans divers champs pris aux prismes objectifs à vision directe
Not Available
| The Distribution of the BD M-Type Stars Along the Galactic Equator.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958ApJ...128..510N&db_key=AST
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Pozíciós és asztrometriai adatok
| Csillagkép: | Vízöntő |
| Rektaszcenzió: | 19h14m58.95s |
| Deklináció: | +14°40'17.8" |
| Vizuális fényesség: | 8.279 |
| RA sajátmozgás: | -16.5 |
| Dec sajátmozgás: | -15.1 |
| B-T magnitude: | 10.924 |
| V-T magnitude: | 8.498 |
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