Investigation of very low mass binaries using VLT/NaCo

Context: Most stars in the galactic stellar population are low-mass stars. Very low-mass (VLM) stars are a subset of the low-mass stars typically defined in terms of the stellar masses ranging from 0.6 M_sun to the hydrogen-burning limit of about 0.075 M_sun. Aim: The observational studies of VLM binaries can provide effective diagnostics for testing the VLM formation scenarios. The small size of VLMs makes them suitable candidates to detect planets around them in the habitable zone. Methods: In this work, using the high-resolution near-infrared adaptive optics imaging from the NaCo instrument installed on the Very Large Telescope, we report the discovery of a new binary companion to the M-dwarf LP 1033-31 and also confirm the binarity of LP 877-72. We have characterized both stellar systems and estimated the properties of their individual components. Results and Conclusions: We have found that LP 1033-31 AB with the spectral type of M4.5+M4.5 has a projected separation of 6.7+/-1.3 AU. On the other hand, with the spectral type of M1+M4, the projected separation of LP 877-72 AB is estimated to be 45.8+/-0.3 AU. We further investigated the masses, surface gravity, radii, and effective temperature of the detected components. The orbital period of LP 1033-31 and LP 877-72 systems are estimated to be ~28 and ~349 yr, respectively. Our analysis suggests that there is a possibility of finding up to `two' exoplanets around LP 877-72 B. In contrast, the maximum probabilities of hosting exoplanets around LP 877-72 A, LP 1033-31 A, and LP 1033-31 B are estimated to be only ~50%.