Shocks and a Giant Planet in the Disk Orbiting BP Piscium?

TL;DR

This paper presents evidence that BP Piscium is a giant star with a protoplanetary disk containing a gap likely caused by a giant planet, with detailed analysis of its dust composition and disk structure.

Contribution

It introduces a model of BP Piscium's disk featuring a planet-induced gap and analyzes the dust mineralogy, supporting the presence of a giant planet affecting disk properties.

Findings

BP Piscium is a first-ascent giant star, not a T Tauri star.

The disk contains sub-micron crystalline and amorphous silicate grains.

Disk shocks from planet interaction produce highly crystalline dust.

Abstract

Spitzer IRS spectroscopy supports the interpretation that BP Piscium, a gas and dust enshrouded star residing at high Galactic latitude, is a first-ascent giant rather than a classical T Tauri star. Our analysis suggests that BP Piscium's spectral energy distribution can be modeled as a disk with a gap that is opened by a giant planet. Modeling the rich mid-infrared emission line spectrum indicates that the solid-state emitting grains orbiting BP Piscium are primarily composed of ~75 K crystalline, magnesium-rich olivine; ~75 K crystalline, magnesium-rich pyroxene; ~200 K amorphous, magnesium-rich pyroxene; and ~200 K annealed silica ('cristobalite'). These dust grains are all sub-micron sized. The giant planet and gap model also naturally explains the location and mineralogy of the small dust grains in the disk. Disk shocks that result from disk-planet interaction generate the highly crystalline dust which is subsequently blown out of the disk mid-plane and into the disk atmosphere.