ABSTRACT
Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1,900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition disks, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition disks show evidence for the presence of young planets in the form of disk asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15 (refs 8, 9). Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disk clearing. With accurate source positions over multiple epochs spanning 2009-2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect Hα emission from the innermost companion, LkCa 15 b, evincing hot (about 10,000 kelvin) gas falling deep into the potential well of an accreting protoplanet.
ABSTRACT
Cystectomy in the treatment of invasive cancer of the urinary bladder is not the only therapeutic modality in this pathology. In selected patients an alternative exists--transurethral resection of the urinary bladder followed by adjuvant concurrent chemotherapy and radiotherapy. The preserving therapy can be recommended to patients over 60 years of age in the presence of a low-grade solitary tumor of a mobile wall of the urinary bladder respectable with preservation of the organ capacity.