Revised Elements and Blazhko Effect of the RR Lyrae Star AR Herculis

TL;DR

This study analyzes extensive observational data of RR Lyrae star AR Herculis, revealing a refined pulsation period and a strong Blazhko effect with a period of about 32 days, along with brightness evolution.

Contribution

It provides a revised period and detailed analysis of the Blazhko effect in AR Herculis using a large dataset and simulations, enhancing understanding of its variability.

Findings

Refined pulsation period of 0.46999746 days.

Detected a strong Blazhko effect with a period of approximately 32 days.

Observed brightness decrease of 22 mmag/year from 2009 to 2015.

Abstract

AR Herculis is an RR Lyrae star of type RRab whose spectral type ranges from A7 to F3. Its visual brightness varies between 10.59 mag and 11.63 mag (V). By analysis of 34,000 measurements from the AAVSO International Database and additional data from the BAV, 116 times of maximum between 2003 and 2015 were derived. For the time span 2009 to 2015, a new period value of P = 0.46999746(145) days was derived from the (O-C) analysis. Furthermore, the derived maximum timings indicate a strong Blazhko effect with a Blazhko period of PB = 32.062(13) days. The evolution of the observed maximum brightness Vmax, which decreased from 2009 to 2015 by 22 mmag/year, is also indicative of a Blazhko effect with PB = 29.528(17) d. The present work investigates the processes in the frequently used (O-C) vs. Vmax diagram by running several simulations based on assumed and observational data.