Gas and Dust Associated with the Strange, Isolated Star Bp Piscium
نویسندگان
چکیده
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 bipolar jets andHerbig-Haro objects is apparently consistent with classification of BP Psc as a preYmain-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 postYmain-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 diskmay be conducive to the current formation of planets, a gigayear or more after the formation of BP Psc itself. Subject headingg s: planetary systems: protoplanetary disks — stars: general Online material: color figures
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