Interstellar Extinction in the Camelopardalis Dark Clouds
An area of about 3times 3 deg in the direction of the Camelopardalisdark clouds is investigated using the Vilnius photometric system.Magnitudes V, color indices, spectral classes, absolute magnitudes,color excesses, interstellar extinctions and distances are determinedfor 126 stars. The interstellar extinction begins at 100 pc distance. Itgrows monotonically and reaches about 2 mag at 300 pc.
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A spectrophotometric survey of stars along the Milky Way. IV
In the present paper a catalogue of spectrophotometric quantities,spectral types, monochromatic magnitudes and colour equivalents is givenfor all stars brighter than the magnitude m4400 = 10.5 in aregion of the Milky Way in Perseus. No absorption is found for starscloser than about r = 100 pc. The absorbing clouds are situated atdistances closer than 1 kpc and at about 2.5 kpc in the local arm andthe Perseus arm, respectively. The space between the two arms is freefrom absorption. It is also concluded that the Perseus arm continuesbeyond l = 140 deg, containing not only hydrogen gas but also dust to atleast l = 150 deg), while the content of OB stars decreases abruptly atl = 140 deg.
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SiO masers in variable stars
Eight new long-period variable stars were found with maser emission fromthe first excited vibrational state of silicon monoxide. One of these, WAndromedae, is a spectral type S star, the second S star known to showSiO emission. A second, T Cephei, is a borderline case between M and S.Although H2O and OH maser emission is commonly found in the SiO stars, asearch of 26 S-type stars for water has been negative, suggesting thatthe effect is real and arises from a chemical difference between the Sstars and those of spectral type M. This may be a result of the high C/Oratio in spectral type S. A new source of ground-state SiO emission wasfound in NGC 2264. This is the first thermal SiO emission observed in amolecular cloud outside of Sgr B2 and Orion A.
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Time variation of some type I OH Mira sources and correlation with their visual magnitude
Abstract image available at:http://adsabs.harvard.edu/abs/1977A&A....58..281F
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OH Mira variables - The light curve shapes and implications for mass loss
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977A&A....57..115B&db_key=AST
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Characteristics of the H2O emission from Mira variables
Absolute fluxes at maximum in the 1.35 cm water-vapor line wereestimated for the H2O mira variables by correcting observed fluxes forthe distances of the stars and phase at the epochs of observations. Theaverage photon rate at maximum is 4 x 10 to 43rd power photons/sec, witha small dispersion. This small dispersion is interpreted in terms of themodel of spherically symmetric expanding envelope. Proximity of the staras major criterion for detection of H2O emission in Miras is inferredfrom the small dispersion. Nine new H2O-Miras were discovered, seven ofwhich belong to the list of Miras closer than about 320 pc.
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Main-line OH emission in long-period variables and infrared stars. I - Discovery of new 1665/1667-MHz OH/IR sources
Abstract image available at:http://adsabs.harvard.edu/abs/1977AJ.....82..150K
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On the stellar velocity of long-period variables and OH maser stars
A statistical analysis of both optical and microwave spectral lines oflong-period variable/molecular maser stars indicates that, contrary tolong-held theories, the stellar radial velocity is not associated witheither the high-velocity OH maser emission features or the opticalabsorption lines. The results presented in this paper, coupled withthose deduced from recent millimeter observations, place the stellarradial velocity between the two OH maser features and between theoptical emission and absorption lines. This supports models of theseobjects in which OH emission comes from the approaching and recedingsides of an expanding circumstellar envelope.
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New H2O sources associated with late-type stars
The paper discusses a search for 1.35-cm water-vapor maser emission in74 late type stars; five new H2O sources were detected. The searchedlist included a few peculiar objects, 13 supergiants, and almost allsouthern long-period Mira variables with spectral class later than M 3and with magnitude brighter than 8 at maximum. The characteristics ofthe microwave line velocities of the known H2O sources associated withvisible stars are discussed.
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Water emission from infrared stars
Twenty-two new infrared stars with microwave water-vapor emission havebeen found, all but four of which are optically identified long-periodvariables. They are heavily reddened, late M stars that commonly showtime variations. Hydroxyl emission is present in all but a fewinstances. Excited-state SiO emission is seen in many H2O-infrared stars(although about half have not yet been checked). Those that are Miravariables always have a visual change of more than 6 magnitudes duringtheir light cycle. Other optical and infrared properties are discussed.
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A study of Mira variables - Implications of OH stars and galactic evolution
A maximum likelihood method has been used to study the properties oftype I OH Mira variables and the kinematical evolution of the Galaxy.The method takes into account dispersion in magnitude and employs propermotions and radial velocities. The V-I excess of type I OH stars withrespect to non OH stars is confirmed, and interpreted in terms of a hot,circumstellar disk around the OH Mira variables. The results support thenotion of a gradual flattening of the Galaxy as proposed by theories ofcollisional collapse.
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Long-period variables - Further work on the correlation of period with OH radial-velocity pattern
Recent radio observations at 18 cm have found a number of new OH stars,all of which exhibit the double-peaked spectrum characteristic of theseobjects. They confirm the correlation between stellar period and thevelocity separation of the two emission peaks. A less stringentcorrelation seems to exist between the I-K color index and the velocityseparation.
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Revised Catalog of Spectra of Mira Variables of Types ME and Se
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974ApJS...28..271K&db_key=AST
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Characteristics of OH emission from infrared stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&A....17..385W&db_key=AST
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Stellar Spectra in Milky way Regions.VI. a Region in Camelopardalis.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956ApJS....2..298M&db_key=AST
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INHABITED SKY
