Gas and Dust Associated with the Strange, Isolated, Star BP Piscium

TL;DR

BP Psc is an unusual star with a dusty disk and jets, possibly a young T Tauri star or an evolved giant, challenging traditional classifications and offering insights into star and planet formation.

Contribution

This study provides multiwavelength observations suggesting BP Psc's nature as either a young star or an evolved giant, with implications for star evolution and disk formation theories.

Findings

BP Psc has a dusty, gaseous disk with active accretion and jets.

It may be a nearby, old T Tauri star or a post-main sequence giant.

The disk could have formed from a low-mass companion star.

Abstract

We have carried out a multiwavelength observational campaign demonstrating some of the remarkable properties of the infrared-bright variable star BP Psc. Surrounded by a compact dusty, gaseous disk, this little-studied late-G (or early-K) type star emits about 75% of its detected energy flux at infrared wavelengths. Evidence for accretion of gas in conjunction with narrow bi-polar jets and Herbig-Haro objects is apparently consistent with classification of BP Psc as a pre-main sequence star, as postulated in most previous studies. If young, then BP Psc would be one of the nearest and oldest known classical T Tauri stars. However, such an evolutionary classification encounters various problems that are absent or much less severe if BP Psc is instead a luminosity class III post-main sequence star. In this case, it would be the first known example of a first ascent giant surrounded by a massive molecular disk with accompanying rapid gas accretion and prominent jets and HH objects. In this model, the genesis of the massive dusty gaseous disk could be a consequence of the envelopment of a low mass companion star. Properties in the disk may be conducive to the current formation of planets, a gigayear or more after the formation of BP Psc itself.