摘要：KIC 12557548 b is the first of a growing class of intriguing disintegrating planet candidates, which lose mass in the form ofa metal-rich vapor that condenses into dust particles. Here, we follow up on two perplexing observations of the system: (1) the transits appeared shallower than average in 2013 and 2014, and (2) the parameters derived from a high-resolution spectrum of the star differed from other results using photometry and low-resolution spectroscopy. We observe five transits of the system with the 61-inch Kuiper telescope in 2016 and show that they are consistent with photometry from the Kepler spacecraft in 2009–2013,suggesting that the dusty tail has returned to normal length and mass. We also evaluate high-resolution archival spectra from the Subaru HDS spectrograph and find them to be consistent with a main-sequence T eff =4440±70K star in agreement with the photometry and low-resolution spectroscopy. This disfavors the hypothesis that planet disintegration affected the analysis of prior high-resolution spectra of this star. We apply Principal Component Analysis to the Kepler long-cadence data to understand the modes of disintegration. There is a tentative 491-day periodicity of the second principal component, which corresponds to possible long-term evolution of the dust grain sizes, though the mechanism on such long timescales remains unclear.
关键词：comets: general;eclipses;planets and satellites: dynamical evolution and stability;stars: fundamental parameters;stars: individual (KIC 12557548, Kepler 1520)
