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Article
Bandwidth effects on interstellar reddening and on theR-ratio
The energy distributions of 85 stars were combined with the transmittance ofB andV tilters and with an interstellar reddening law in order to investigate the effects of the bandwidth on the colour excess and on t...
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Article
On the period-luminosity-colour relation for galactic Cepheids
A period-luminosity-colour relation is derived from the data of 29 galactic Cepheids with known distances collected from the literature, and is then compared with the simpler period-luminosity relation. The in...
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Article
The empirical mass-luminosity relation
On the basis of the most recent data for visual and spectrophotometric binaries, the empirical mass-luminosity relation has been investigated. It is shown that, for the sample collected, the relation may be di...
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Article
The cycle area of RR Lyr-stars in two-colour diagrams
It is shown that a relation exists between the period and the area of the closed counter-clockwise path described in a two-colour diagram by an RR Lyrae star. Moreover, this area may be correlated with the wor...
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Article
Combined Light and Velocity Measurements of the Variable Star 12 Lacertae
DURING the summer and autumn of 1956, fifteen observatories co-operated in securing brightness and radial velocity measurements of the variable star 12 Lacertae. The variable belongs to the group of Beta Canis...
