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First CCD measurements in the {DELTA}a system for detecting CP2 stars.
This is the first time that CCD-photometry in the three filter {DELTA}asystem (Maitzen, 1976A&A....52..223M) was carried out after twodecades of classical photoelectric photometry. The aim is to extend thesuccessful search for chemically peculiar stars to more and distant openclusters as well as far galactic fields. In this paper we presentCCD-photometry for a sample of 25 field stars with publishedspectroscopic peculiarity types. 22 of them show discordance betweentheir Michigan catalogue types (non-peculiar) and the Bidelman &MacConnell (1973AJ.....78..678B; BC) peculiarity assignments. Eightstars are peculiar in {DELTA}a (five of them also in the Geneva index{DELTA}(V1-G)) thus supporting BC, mainly among their Silicon stardiscoveries. Considering cases where Silicon line enhancements wereinterpreted as peculiar instead as indicator of higher luminosity by BC,and the perfect detection of the three unambiguous peculiar stars, inaddition to the achievement of an accuracy of 0.003mags, we arejustified to conclude that the performance of our CCD-{DELTA}aphotometry perfectly matches the requirements of the conventionalphotometric technique and thus opens the way to observations of fainterstars.
| A list of candidates for high-velocity AP stars
'Reduced proper motion' is used to select from a catalog of over fifteenhundred Ap stars those that probably have a high velocity. A list of 164candidates is presented, 22 of them having very probably high velocity.Some of them could be the first specimens of late Ap stars with highvelocity. The possible relation to horizontal branch stars is alsodiscussed.
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Observation and Astrometry data
| Constellation: | Scorpius |
| Right ascension: | 16h35m23.60s |
| Declination: | -34°00'49.7" |
| Apparent magnitude: | 9.172 |
| Proper motion RA: | 6.2 |
| Proper motion Dec: | 4.7 |
| B-T magnitude: | 9.651 |
| V-T magnitude: | 9.212 |
Catalogs and designations:
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