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Joao Bento

Publications and source records attributed to Joao Bento.

20 records · Page 2Linked to original sources

DT Serpentis: neither a symbiotic star nor a planetary nebula associate

We present an alternative interpretation for the putative symbiotic star DT Serpentis, and its proposed planetary nebula (PN), recently announced by Munari et al. Our analysis is based on their data combined with additional archival data trawled from Virtual Observatory databases. We show that the star known as DT Ser is not a symbiotic star, and is merely superposed on the newly discovered but unrelated background PN. There is no evidence for any periodic variability for DT Ser as expected for a symbiotic star. We further establish that there is no physical association between DT Ser and the PN, which has a considerably higher extinction, befitting the larger distance we estimate. The significantly different radial velocities of the star and nebula also likely preclude any association. Finally, we show that the mid-infrared source detected by the IRAS and WISE surveys is actually coincident with the PN so there is no evidence for DT Ser being a dusty post-AGB star.

astro-ph.SR↗

The Next Generation Transit Survey (NGTS)

The Next Generation Transit Survey (NGTS) is a new ground-based sky survey designed to find transiting Neptunes and super-Earths. By covering at least sixteen times the sky area of Kepler we will find small planets around stars that are sufficiently bright for radial velocity confirmation, mass determination and atmospheric characterisation. The NGTS instrument will consist of an array of twelve independently pointed 20cm telescopes fitted with red-sensitive CCD cameras. It will be constructed at the ESO Paranal Observatory, thereby benefiting from the very best photometric conditions as well as follow up synergy with the VLT and E-ELT. Our design has been verified through the operation of two prototype instruments, demonstrating white noise characteristics to sub-mmag photometric precision. Detailed simulations show that about thirty bright super-Earths and up to two hundred Neptunes could be discovered. Our science operations are due to begin in 2014.

astro-ph.EP↗