[en] Photometric observations of 13 Ap stars made at the European Southern Observatory at La Silla during November 1977 and December 1978 are reported. Observations were made in the uvby with the four-channel photometer at the 40-cm telescope in November, and with the one-channel photometer at the 50-cm telescope in December. Light variations with periods from 0.724 to 4.64 days are obtained for 11 of the stars, including the Hg-Mn star HR 2202, which was believed not to vary. Extremely small variations are observed in Upsilon 4 Eri, with a possible period of 0.51 days, although the two Mn components are likely to vary independently. HR 1800 was not observed to vary over two-week observation period. The stars 20 Eri, HR 1194, Alpha Dor, 11 Ori and HD 36916 are also noted to exhibit relatively large variations for Ap stars.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Renson, Pierre ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Evol. et stabilité des étoiles et des amas d'étoiles (ESEA)
Manfroid, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Language :
English
Title :
Photometric variations in Ap stars observable at La Silla in November and December