Naslov
Characterizing Low-mass Binaries from Observation of Long-timescale Caustic-crossing Gravitational Microlensing Events

Autori
Shin, I.-G. ; ... ; Dominis Prester, Dijana ; ... ; Zub, M.

Izvornik
The Astrophysical journal (0004-637X) 755 (2012), 2; 91-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
binaries: general; gravitational lensing: micro

Sažetak
Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 M sun and 0.39 M sun for MOA-2011-BLG-090 and 0.57 M sun and 0.17 M sun for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
PLANET Collaboration

POVEZANOST RADA