A HST/WFC3 Search for Substellar Companions in the Orion Nebula Cluster

Strampelli, G. M.; Aguilar, Jonathan; Aparicio, A.; Piotto, Giampaolo; Pueyo, Laurent; Robberto, Massimo
Bibliographical reference

American Astronomical Society, AAS Meeting #231, id.#414.07

Advertised on:
1
2018
Number of authors
6
IAC number of authors
1
Citations
0
Refereed citations
0
Description
We present new results relative to the population of substellar binaries in the Orion Nebula Cluster. We reprocessed HST/WFC3 data using an analysis technique developed to detect close companions in the wings of the stellar PSFs, based on the PyKLIP implementation of the KLIP PSF subtraction algorithm. Starting from a sample of ~1200 stars selected over the range J=11-15 mag, we were able to uncover ~80 candidate companions in the magnitude range J=16-23 mag. We use the presence of the 1.4 micron H2O absorption feature in the companion photosphere to discriminate 32 bona-fide substellar candidates from a population of reddened background objects. We derive an estimate of the companion mass assuming a 2Myr isochrone and the reddening of their primary. With 8 stellar companions, 19 brown dwarfs and 5 planetary mass objects, our study provide us with an unbiased sample of companions at the low-mass end of the IMF, probing the transition from binary to planetary systems.