Adaptive Optics Imaging Can Break the Central Caustic Cusp Approach Degeneracy in High-magnification Microlensing Events

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dc.citation.issue5
dc.citation.volume164
dc.contributor.authorTerry SK
dc.contributor.authorBennett DP
dc.contributor.authorBhattacharya A
dc.contributor.authorKoshimoto N
dc.contributor.authorBeaulieu J-P
dc.contributor.authorBlackman JW
dc.contributor.authorBond IA
dc.contributor.authorCole AA
dc.contributor.authorLu JR
dc.contributor.authorMarquette JB
dc.contributor.authorRanc C
dc.contributor.authorRektsini N
dc.contributor.authorVandorou A
dc.date.accessioned2023-11-12T20:54:11Z
dc.date.accessioned2023-11-20T01:38:18Z
dc.date.available2022-10-26
dc.date.available2023-11-12T20:54:11Z
dc.date.available2023-11-20T01:38:18Z
dc.date.issued2022-11-01
dc.description.abstractWe report new results for the gravitational microlensing target OGLE-2011-BLG-0950 from adaptive optics images using the Keck Observatory. The original analysis by Choi et al. and reanalysis by Suzuki et al. report degenerate solutions between planetary and stellar binary lens systems. This particular case is the most important type of degeneracy for exoplanet demographics because the distinction between a planetary mass or stellar binary companion has direct consequences for microlensing exoplanet statistics. The 8 and 10 yr baselines allow us to directly measure a relative proper motion of 4.20 ± 0.21 mas yr−1, confirming the detection of the lens star system and ruling out the planetary companion models that predict a ∼4× smaller relative proper motion. The Keck data also rule out the wide stellar binary solution unless one of the components is a stellar remnant. The combination of the lens brightness and close stellar binary light-curve parameters yields primary and secondary star masses of M A = 1.12 − 0.09 + 0.11 and M B = 0.47 − 0.10 + 0.13 M ☉ at a distance of D L = 6.70 − 0.30 + 0.55 kpc and a projected separation of 0.39 − 0.04 + 0.05 au. Assuming that the predicted proper motions are measurably different, the high-resolution imaging method described here can be used to disentangle this degeneracy for events observed by the Roman exoplanet microlensing survey using Roman images taken near the beginning or end of the survey.
dc.description.confidentialfalse
dc.identifier.citationTerry SK, Bennett DP, Bhattacharya A, Koshimoto N, Beaulieu JP, Blackman JW, Bond IA, Cole AA, Lu JR, Marquette JB, Ranc C, Rektsini N, Vandorou A. (2022). Adaptive Optics Imaging Can Break the Central Caustic Cusp Approach Degeneracy in High-magnification Microlensing Events. Astronomical Journal. 164. 5.
dc.identifier.doi10.3847/1538-3881/ac9518
dc.identifier.eissn1538-3881
dc.identifier.elements-typejournal-article
dc.identifier.issn0004-6256
dc.identifier.number217
dc.identifier.urihttps://mro.massey.ac.nz/handle/10179/69173
dc.languageEnglish
dc.publisherIOP Publishing on behalf of the American Astronomical Society
dc.publisher.urihttps://iopscience.iop.org/article/10.3847/1538-3881/ac9518
dc.relation.isPartOfAstronomical Journal
dc.rightsCC BY 4.0
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectGravitational microlensing (672)
dc.subjectBinary lens microlensing (2136)
dc.subjectHighresolution microlensing event imaging (2138)
dc.subjectBinary stars (154)
dc.subjectGalactic bulge (2041)
dc.titleAdaptive Optics Imaging Can Break the Central Caustic Cusp Approach Degeneracy in High-magnification Microlensing Events
dc.typeJournal article
pubs.elements-id457992
pubs.organisational-groupOther
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