1. The transiting dust clumps in the evolved disc of the Sun-like UXor RZ Psc
- Author
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Grant M. Kennedy, Matthew A. Kenworthy, Joshua Pepper, Joseph E. Rodriguez, Robert J. Siverd, Keivan G. Stassun, and Mark C. Wyatt
- Subjects
variable stars ,protoplanetary discs ,debris discs ,circumstellar matter ,Science - Abstract
RZ Psc is a young Sun-like star, long associated with the UXor class of variable stars, which is partially or wholly dimmed by dust clumps several times each year. The system has a bright and variable infrared excess, which has been interpreted as evidence that the dimming events are the passage of asteroidal fragments in front of the host star. Here, we present a decade of optical photometry of RZ Psc and take a critical look at the asteroid belt interpretation. We show that the distribution of light curve gradients is non-uniform for deep events, which we interpret as possible evidence for an asteroidal fragment-like clump structure. However, the clumps are very likely seen above a high optical depth midplane, so the disc’s bulk clumpiness is not revealed. While circumstantial evidence suggests an asteroid belt is more plausible than a gas-rich transition disc, the evolutionary status remains uncertain. We suggest that the rarity of Sun-like stars showing disc-related variability may arise because (i) any accretion streams are transparent and/or (ii) turbulence above the inner rim is normally shadowed by a flared outer disc.
- Published
- 2017
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