Photometry of δ Sct-type and Related Stars: Results of AD Ari, IP Vir and YZ Boo
Photometric results of three δ Scuti stars, AD Ari, IP Vir and YZBoo from new observations obtained at the Xinglong Station of theBeijing Astronomical Observatory (BAO) during 2000 and 2001 arereported. We present here the preliminary analyses. Detailed studies ofthese stars based on additional data will be published separately.
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The mode identification and physical parameter determination of the delta Scuti star SAO 16394
The star SAO 16394 was observed with the 85 cm telescope at the XinglongStation of Beijing Astronomical Observatory of China from 8 to 17 April1997 and identified as a new delta Scuti star in 1998. In order todetermine its frequencies and pulsation modes accurately it was observedat the Xinglong Station in 1998 and 1999, and at the Sierra NevadaObservatory (Spain) in 1999. Period analyses were made for our data set(1997) and the data set (1997-1999). From the combined data set(1997-1999), the values of two frequencies are: 16.8493 and 23.0613cd-1. From our photoelectric observations, we obtained twophysical parameters of SAO 16394: log L/Lsun = 1.16, logTeff = 3.92. We calculated the evolution sequences of stellarmodels with 1.00-2.00 solar mass in steps of 0.05Msun and 8physical parameters of each evolutionary phase. We suggest that theevolutionary sequence of the 1.85 Msun model might representthe evolutionary sequence of SAO 16394. The 30th evolutionary phase ofthe evolutionary sequence of the model with 1.85 Msun mightrepresent the current location of SAO 16394. Depending on the Q values(Q1 = 0.0336 day, Q2 = 0.0246 day) and frequencyratio f1/f2 = 0.7306 we identify f1(16.8493 cd-1) as the radial fundamental mode, f2(23.0613 cd-1) as its first overtone.
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A revised catalogue of delta Sct stars
An extensive and up-dated list of delta Sct stars is presented here.More than 500 papers, published during the last few years, have beenrevised and 341 new variables have been added to our last list, sixyears ago. This catalogue is intended to be a comprehensive review onthe observational characteristics of all the delta Sct stars known untilnow, including stars contained in earlier catalogues together with othernew discovered variables, covering information published until January2000. In summary, 636 variables, 1149 references and 182 individualnotes are presented in this new list. Tables 1 and 2 will be accessibleonly in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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The 75th Name-List of Variable Stars
We present the next regular Name-List of variable stars containinginformation on 916 variable stars recently designated in the system ofthe General Catalogue of Variable Stars.
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A New delta Scuti Variable Star - SAO 16394
Not Available
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Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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The Delta Scuti star HD 127759
The results are reported of six nights of V-band observations of thenewly discovered Delta Scuti variable HD 127759 during April 3-21, 1991and its Stromgren uvby(beta) photometry. The period analysis indicatesthat HD 127759 is a single-sine frequency-dominant pulsation variablewith a frequency of 14.78626 cycle/d and an amplitude of 0.0199 m. Thetimes of maximum are given. The star is located at the blue edge of theDelta Scuti variable instability strip, with T(eff) about 8400 K andM(V) about 0.93 m.
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HD 127759: a New delta Scuti Variable
Not Available
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HD 127759 is possibly a short period variable.
Not Available
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The distance to the high-velocity clouds - Mass infall and galactic disk formation
The high-velocity neutral hydrogen complex C in optical (Ca K)absorption against stars at distances of 1-2 kpc has been detected,confirming a previous tentative detection and placing an upper limit onthe distance to this complex. A similar (though as yet more uncertain)limit is placed to the distance to complex A. No complex is detected inabsorption against any nearby star, effectively ruling out models inwhich the clouds are formed by supershells in the local disk. If thesedistances are representative of the bulk of the high-velocity clouds,the local mass infall rate is 6 x 10 to the -9th solar mass/sq pc/yr,which would supply the disk column density in 10 billion yr. The cloudslie above the bulk of the disk, and it is shown how they may be used tomeasure the pressure of the halo and to place an upper bound on themetagalactic UV flux.
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INHABITED SKY
