THE ACTIVITY AND VARIABILITY OF THE SUN AND SUN-LIKE STARS. II. CONTEMPORANEOUS PHOTOMETRY AND SPECTROSCOPY OF BRIGHT SOLAR ANALOGS

摘要: We present 14 years of contemporaneous photometric and spectroscopic observations 28 solar analog stars, taken with the Tennessee State University Automatic Photometric Telescopes at Fairborn Observatory Solar-Stellar Spectrograph Lowell Observatory. These are best observed most nearly Sun-like targets in our magnitude-limited (V ≤ 7.5) sample. The correlations between luminosity activity reveal expected inverse activity-brightness for active stars. Strong direct brightness not prevalent less age but precision limited. Sun does appear to have unusually low variability when compared inactive analogs. evidence that index R'HK is a good discriminant Maunder Minimum candidate On basis star appears transitioned from low-variability state cycling state, we investigate regime which stars might switch faculae-dominated spot-dominated variations.