SHARDDS project: Discovery of the binary system HD 53842A/B

We present the first results of the SHARDDS project, which is a high-resolution H-band imaging survey aimed at discovering and 
characterizing warm dust discs from scattered light emission around all bright, nearby debris discs using the planet finder 
instrument SPHERE for the ESO's VLT telescope.
VLT/SPHERE permits to detect extended scattered light from discs with unprecedented capabilities that improve the inner working 
angle and sensitivity by means of its extreme-AO turbulence compensation system. We use it in combination with the classical 
imaging mode of the camera IRDIS.
We have discovered that one of our targets, HD 53842 is indeed a long period binary system consisting of  a main sequence 
primary star of spectral type F5V and an M dwarf, with a separation of 1.4 arcsec between the components and a brightness ratio 
of 21 from the SPHERE H-band image. 
The binary system presents a high proper motion but a similar configuration in the NICMOS/NIC2 F190N and F110W high-angular 
resolution images, which were obtained more than 9.5 years before. We have determined the fundamental properties of the two 
components from stellar evolution models and stellar atmosphere models.
We also discuss the nature and origin of any possible infrared excess in the binary system.