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Strömgren photometry and spectroscopy of the ? Scuti stars 7 Aql and 8 Aql
Photometric (uvby-?) and spectroscopic observations of the ?Scuti variables 7 Aql and 8 Aql are described. The Strömgrenstandard indices and physical parameters of both stars are derived.Spectral types of F0V and F2III have been assigned to 7 Aql and 8 Aql,respectively considering the results from both spectroscopy andphotometry. Differential uvby light curves were also analyzed. A attemptof multicolour mode identification is carried out.
| CCD photometry of ? Scuti stars 7 Aql and 8 Aql
As a continuation of the study of the Delta Scuti stars 7 Aql and 8 Aql,new CCD photometric data were acquired in 2007. We present a periodanalysis of these data that confirms the dominant modes detected in eachstar in the framework of the STEPHI XII campaign in 2003.
| Multisite Observations of δ Scuti Stars 7 Aql and 8 Aql (a New δ Scuti Variable): The Twelfth STEPHI Campaign in 2003
We present an analysis of the pulsation behavior of the δ Scutistars 7 Aql (HD 174532) and 8 Aql (HD 174589), a new variable star,observed in the framework of the STEPHI XII campaign during 2003 Juneand July; 183 hr of high-precision photometry were acquired by usingfour-channel photometers at three sites on three continents during 21days. The light curves and amplitude spectra were obtained following aclassical scheme of multichannel photometry. Observations in differentfilters were also obtained and analyzed. Six and three frequencies havebeen unambiguously detected above a 99% confidence level in the range190-300 μHz and 100-145 μHz in 7 Aql and 8 Aql, respectively. Acomparison of observed and theoretical frequencies shows that 7 Aql and8 Aql may oscillate with p-modes of low radial orders, typical amongδ Scuti stars. In terms of radial oscillations the range of 8 Aqlgoes from n=1 to 3, while for 7 Aql the range spans from n=4 to 7.Nonradial oscillations have to be present in both stars as well. Theexpected range of excited modes according to a nonadiabatic analysisgoes from n=1 to 6 in both stars.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Preparing the COROT space mission: Incidence and characterisation of pulsation in the lower instability strip
By pursuing the goal to find new variables in the COROT field-of-view wecharacterised a sample of stars located in the lower part of theinstability strip. Our sample is composed of stars belonging to the diskpopulation in the solar neighbourhood. We found that 23% of the starsdisplay multiperiodic light variability up to a few mmag in amplitude,i.e., easily detectable on a single night of photometry. uvbybetaphotometry fixed most of the variables in the middle of the instabilitystrip and high-resolution spectroscopy established that they have vsin i>100 km s-1. An analysis of the Rodríguez &Breger (\cite{Rodr01}) sample (delta Sct stars in the whole Galaxy)shows slightly different features, i.e., most delta Sct stars have a0.05-mag redder (b-y)0 index and lower vsin i values.Additional investigation in the open cluster NGC 6633 confirms the sameincidence of variability, i.e., around 20%. The wide variety ofpulsational behaviours of delta Sct stars (including unusual objectssuch as a variable beyond the blue edge or a rapidly rotatinghigh-amplitude pulsator) makes them very powerful asteroseismic tools tobe used by COROT. Being quite common among bright stars, delta Sctstars are suitable targets for optical observations from space.Based on observations collected at the S. Pedro Martír, SierraNevada, La Silla, Haute-Provence, South African and Roque de LosMuchachos observatories.
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| Flamsteed stars not contained in the Yale "Catalogue of Bright Stars"
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Observation and Astrometry data
| Constellation: | Aquila |
| Right ascension: | 18h51m05.41s |
| Declination: | -03°15'40.1" |
| Apparent magnitude: | 6.891 |
| Distance: | 129.366 parsecs |
| Proper motion RA: | -49.1 |
| Proper motion Dec: | -57 |
| B-T magnitude: | 7.21 |
| V-T magnitude: | 6.918 |
Catalogs and designations:
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