Working Group on the Magellanic Clouds

Extract

A Symposium on the Magellanic Clouds was sponsored by E.S.O. in Santiago, Chile, in 1969 March in connection with the dedication of the E.S.O. Observatory at La Silla. Review papers on the Clouds have been written by Westerlund and Bok (J. R. astr. Soc. Can., 63, 105).

Gascoigne (Mon. Not. R. astr. Soc., 146, 1) has prosecuted further his P-L work on Cloud cepheids and finds V = 17·58 — 3·072 logP (7 LMC cepheids), V = 17·73 — 2·879 logP (13 SMC cepheids) while 25 SMC, 18 LMC and 13 galactic cepheids obey the Sandage relation M_v = a – 3·609 logP + 2·52(<B> – <V>).

This implies moduli of 18·73 (LMC) and 19·36 (SMC), but Gascoigne recommends, in the light of other evidence, adoption of moduli 18·75 (LMC) and 19·2 (SMC). The colours of SMC cepheids are 0.^m1 bluer than those in the Galaxy and they may be somewhat underluminous for their periods.