SECOND GENERATION PLANETS

摘要: Planets are typically thought to form in protoplanetary disks left over from protostellar disk of their newly formed host star. However, an additional planetary formation route may exist old evolved binary systems. In such systems stellar evolution could lead the symbiotic stars, where mass transferred expanding star its companion accretion around it. Such a provide necessary environment for second generation planets both circumstellar or circumbinary congurations. Pre-existing �rst surviving post-MS serve as seeds for, and/or interact with, planets, possibly forming atypical Second should be found white dwarf systems, and show various observational signatures. Most notably, which inaccessible, less favorable, forrst planets. The orbital phase space available forbidden (in terms system stability) pre-evolved progenitor bina ries. addition metal poor environments globular clusters double compact object binaries. Observations unfavorable regions uniquely identify character. Finally, we point out few observed candidate including PSR B1620-26 cluster), Gl 86, HD 27442 all currently planet candidates. A origin these naturally explain unique