Plaut 3-1933 , the SIMBAD biblio

Near-infrared photometry (JHKL'M) was obtained for 78 semiregular variables (SRVs) in field #3 of the Palomar-Groningen survey (PG3, l=0°, b=-10°). Together with a sample of Miras in this field a comparison is made with a sample of field SRVs and Miras. The PG3 SRVs form a sequence (period-luminosity & period-colour) with the PG3 Miras, in which the SRVs are the short period extension to the Miras. The field and PG3 Miras follow the same P/(J-K)₀ relation, while this is not the case for the field and PG3 SRVs. Both the PG3 SRVs and Miras follow the Sgr I period-luminosity relation adopted from Glass et al. (1995). They are likely pulsating in the fundamental mode and have metallicities spanning the range from intermediate to approximately solar.