We analyse the results of a 5.5‐yr photometric campaign that monitored 247 southern, semiregular variables with relatively precise Hipparcos parallaxes to demonstrate an unambiguous detection of red giant branch (RGB) pulsations in the solar neighbourhood. We show that Sequence A′ contains a mixture of asymptotic giant branch and RGB stars, as indicated by a temperature‐related shift at the tip of the red giant branch. Large Magellanic Cloud (LMC) and Galactic sequences are compared in several ways to show that the period–luminosity sequence zero‐points have a negligible metallicity dependence. We describe a new method to determine absolute magnitudes from pulsation periods and calibrate the LMC distance modulus using Hipparcos parallaxes to find μLMC= 18.54 ± 0.03 mag. Several sources of systematic error are discussed to explain discrepancies between the Massive Compact Halo Object and Optical Gravitational Lensing Experiment sequences in the LMC. We derive a relative distance modulus of the Small Magellanic Cloud relative to the LMC of Δμ= 0.41 ± 0.02 mag. A comparison of other pulsation properties, including period–amplitude and luminosity–amplitude relations, confirms that RGB pulsation properties are consistent and universal, indicating that the RGB sequences are suitable as high‐precision distance indicators. The M giants with the shortest periods bridge the gap between G and K giant solar‐like oscillations and M‐giant pulsation, revealing a smooth continuity as we ascend the giant branch.
We present the results of a 5.5-year CCD photometric campaign that monitored
261 bright, southern, semi-regular variables with relatively precise Hipparcos
parallaxes. The data are supplemented with independent photoelectric
observations of 34 of the brightest stars, including 11 that were not part of
the CCD survey, and a previously unpublished long time-series of VZ Cam.
Pulsation periods and amplitudes are established for 247 of these stars, the
majority of which have not been determined before. All M giants with sufficient
observations for period determination are found to be variable, with 87% of the
sample (at S/N >= 7.5) exhibiting multi-periodic behaviour. The period ratios
of local SRVs are in excellent agreement with those in the Large Magellanic
Cloud. Apparent K-band magnitudes are extracted from multiple NIR catalogues
and analysed to determine the most reliable values. We review the effects of
interstellar and circumstellar extinction and calculate absolute K-band
magnitudes using revised Hipparcos parallaxes.Comment: 18 pages, 15 figures; accepted for publication in Monthly Notices of
the Royal Astronomical Societ
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.