Blazhko type fundamental-mode RR Lyrae stars in the globular cluster, M3

Abstract

Blazhko stars from the extended $BV{I}_{\mathrm{C}}$ time series of RRab stars in the globular cluster, M3, are analysed. This is the largest sample of Blazhko stars with full details of their Blazhko properties in a homogeneous stellar system. Blazhko periods and light-curve solutions are determined/estimated for 83 fundamental-mode variables. The lack of phase modulation in Oosterhoff-type~II stars and the diminishing relative strength of the modulation in long-period Oosterhoff-type~I stars are the regular tendencies found between the pulsation and modulation properties of Blazko stars. Similarly to previous results, no modulation of the longest-period stars is detected. The onset of the modulation in a previously regular RRab star, and the similar distribution of modulated and non-modulated stars imply that the modulation is a temporal property of RRL stars, which may occur at any time in any RRab star except the coolest ones. Comparing the modulation periods in M3 and in other samples of Blazhko stars, the mean log$(P_{\mathrm{mod}})$ value is found to depend on the metallicity of the system. The separation of the temperature- and radius-change induced variations supports our previous finding that the photometric radius variation does not show any modulation. The pulsation-averaged mean brightness and temperature of Blazhko stars are found to be larger in the large-amplitude phase of the modulation than in the small-amplitude phase. The larger the amplitude of the modulation, the larger changes of the mean parameters are detected.

18 pages, 12 figures Accepted for publication in MNRAS

References in corpus (12)

• Kepler photometry of RRc stars: peculiar double-mode pulsations and period doubling
• Blazhko-type modulation in the double-mode RR Lyrae stars of the OGLE Galactic bulge collection
• Blazhko effect in the Galactic bulge fundamental mode RR~Lyrae stars I: Incidence rate and differences between modulated and non-modulated stars
• Multicolour CCD photometry of the variable stars in globular cluster M3
• A Near-infrared RR Lyrae census along the southern Galactic plane: the Milky Way's stellar fossil brought to light
• Discovery of a new group of double-periodic RR Lyrae stars in the OGLE-IV photometry
• The historical vanishing of the Blazhko effect of RR Lyr from GEOS and Kepler surveys
• Blazhko modulation in the infrared
• The Blazhko behaviour of RR Geminorum II -- long-term photometric results
• A new method for determining physical parameters of fundamental mode RR Lyrae stars from multicolour light curves
• The SERMON project: 48 new field Blazhko stars and an investigation of modulation-period distribution
• The first Baade-Wesselink analysis of Blazhko RR Lyrae stars: discrepancies between photometrically and spectroscopically determined radius variations

Cited by in corpus (6)

• Blazhko effect in the Galactic bulge fundamental mode RR Lyrae stars II: Modulation shapes, amplitudes and periods
• Near-infrared Census of RR Lyrae variables in the Messier 3 globular cluster and the Period--Luminosity Relations
• On the Use of Field RR Lyrae as Galactic Probes. VI. Mixed mode RR Lyrae variables in Fornax and in nearby dwarf galaxies
• Multi-wavelength Photometric Study of RR Lyrae Variables in the Globular Cluster NGC 5272 (Messier 3)
• Digging Deeper for RR Lyrae Stars with Low Modulation Amplitudes
• A search for photometric variability towards the globular cluster M3 with the TWenty Inch Survey Telescope