Journal article · Preprint article
Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events
Chungbuk National University1
Massey University2
The University of Auckland3
Victoria University of Wellington4
Okayama Astrophysical Observatory5
Nagano National College of Technology6
Tokyo Metropolitan College of Industrial Technology7
European Southern Observatory8
Max Planck Institute9
Liverpool John Moores University10
Las Cumbres Observatory Global Telescope Network, Inc.11
University of Warsaw12
Qatar Foundation13
University of Stuttgart14
Georg-August-Universität Göttingen15
Chinese Academy of Sciences16
Aarhus University17
University of Copenhagen18
Natural History Museum of Denmark19
National Space Institute, Technical University of Denmark20
Astrophysics, National Space Institute, Technical University of Denmark21
ESO Headquarters22
Osaka University23
University of Manchester24
Sharif University of Technology25
Institut d'Astrophysique et de Géophysique26
Keele University27
Heidelberg University 28
Instituto Nacional de Pesquisas Espaciais29
Stardome Observatory and Planetarium30
Texas A&M University31
Institute for Advanced Study32
Korea Astronomy and Space Science Institute33
University of Salerno34
Centre for Backyard Astrophysics35
Kumeu Observatory36
Perth Exoplanet Survey Telescope37
University of Canterbury38
Sorbonne Université39
University of Tasmania40
University of Rijeka41
Vienna University of Technology42
South African Astronomical Observatory43
Space Telescope Science Institute44
University of St Andrews45
Université Fédérale Toulouse Midi-Pyrénées46
Ohio State University47
Nagoya University48
University of Notre Dame49
...and 39 moreDespite 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⊙ and 0.39 M⊙ for MOA-2011-BLG-090 and 0.57 M⊙ and 0.17 M⊙ 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.
| Language: | English |
|---|---|
| Year: | 2012 |
| Pages: | 91 |
| ISSN: | 15384357 , 0004637x , 15384365 and 00670049 |
| Types: | Journal article and Preprint article |
| DOI: | 10.1088/0004-637X/755/2/91 |
| ORCIDs: | Hornstrup, Allan and 0000-0001-7303-914X |
