系外行星研究组知识库

We present an analysis of the starspot properties and chromospheric activity on HD 134319 using high-precision photometry by Transiting Exoplanet Survey Satellite (TESS) in sectors 14-16 (T1) and 21-23 (T2) and high-resolution spectroscopy by the ELODIE spectrograph on 1.93-m telescope of Observatoire de Haute-Provence (OHP/ELODIE) and the High Resolution Echelle Spectrometer on Keck 10-m telescope of W. M. Keck Observatory (Keck/HIRES) during the years 1995-2013. We applied a two-spot model with generalized Lomb-Scargle (GLS) periodogram determined period of P = 4.436391 +/- 0.00137 d to model chunks sliding over TESS light curve. We also measured the relative equivalent widths of Ca ii H and K, H beta and H alpha emissions by subtracting the overall spectrum from individual spectra. It was found that a two-spot configuration, namely a primary, slowly evolving and long-lasting spot (P) plus a secondary, rapidly evolving spot (S), was capable of explaining the data, although the actual starspot distribution cannot be derived from the collected data. Despite the spot radius-latitude degeneracy revealed in the best-fitting solutions, a sudden alternation between P and S radii followed by a gradual decrease of S in T1 and a decrease of both P and S from T1 to T2 were significant, corresponding to the evolution of magnetic activity. In addition, S revealed rotation and an oscillatory longitude migration synchronized to P in T1, but had a much larger migration than P in T2. This might indicate the evolution of the internal magnetic configuration. Chromospheric activity indicators were found to be tightly correlated with each other and revealed rotational modulation as well as a long-term decrease of emissions, implying the existence and evolution of magnetic activity on HD 134319.