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Confirmation among visual multiples of an increase of AP stars with age Open clusters with ages below certain threshold values contain no Apstars and those with greater ages contain numbers of Ap stars thatapparently increase with age. But in view of the few young clustersstudied, the data could also be interpreted in terms of randomdifferences in the frequencies of Ap stars between individual clusters,rather than an age effect. Data on 77 field visual multiple systems(that originated from many different clusters and associations) in whichthe primaries are O5-A1 stars and the secondaries occur in the absolutemagnitude range of the Ap stars were, therefore, obtained. Againspectral classification shows no Ap stars in systems with ages notgreater than 1,000,000 yr and a steady increase in Ap stars thereafter.The numerical agreement with the cluster data is good, confirming thatthe cluster data are exhibiting a real age effect.
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Observation and Astrometry data
Constellation: | Serpens |
Right ascension: | 18h42m53.31s |
Declination: | +05°44'27.9" |
Apparent magnitude: | 9.137 |
Proper motion RA: | -2.5 |
Proper motion Dec: | -9 |
B-T magnitude: | 9.301 |
V-T magnitude: | 9.151 |
Catalogs and designations:
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