Confirmation of the Ogle-2005-BLG-169 Planet Signature and Its Characteristics With Lens–source Proper Motion Detection

Abstract

We present Keck NIRC2 high angular resolution adaptive optics observations of the microlensing event OGLE-2005-BLG-169Lb, taken 8.21 years after the discovery of this planetary system. For the first time for a microlensing planetary event, the source and the lens are completely resolved, providing a precise measurement of their heliocentric relative proper motion, 7.44 0.17 rel,helio m =  mas yr −1 . This confirms and refines the initial model presented in the discovery paper and rules out a range of solutions that were allowed by the microlensing light curve. This is also the first time that parameters derived from a microlensing planetary signal are confirmed, both with the Keck measurements, presented in this paper,and independent measurements obtained with the Hubble Space Telescope in I V , and Bbands, presented in a companion paper. Hence, this new measurement of rel,helio m , as well as the measured brightness of the lens in Hband, enabled the mass and distance of the system to be updated:a Uranus-mass planet (m M 13.2 1.3 p =  Å ) orbiting a K5-type main sequence star (M M * 0.65 0.05 =   ) separated by a 3.4 0.3 =  AU, at the distance D 4.0 0.4 L =  kpc from us.

OGLE-2013-BLG-1761Lb: A Massive Planet around an M/K Dwarf

“…2017). The lens detection can be confirmed by measuring the lens-source relative proper motion (Batista et al 2015;Bennett et al 2015). Figure 7 shows the probability distribution of I-, V-, H-, and K-band magnitudeof the lens star with extinction.…”

Discovery of a Gas Giant Planet in Microlensing Event Ogle-2014-BLG-1760

“…For each MCMC fit, the source distance is picked randomly from this distribution. From emperical mass-luminosity relations (Henry & McCarthy 1993;Henry et al 1999;Delfosse et al 2000) and massdistance relations, we estimated the lens distance, host-star and planet mass, host-star brightness, and host-star and planet projected separation using a method similar to that used by Batista et al (2015) and Bennett et al (2015). Then, we calculated mean, median, and posterior distributions for each parameter from all of these MCMC fits, as seen in Table 3 , spans the range from the mass of Saturn to that of Jupiter.…”

“…Since the lens-source relative proper motion is m =  -6.55 1.12 mas yr rel 1 , the source and lens will be separated by ∼1 HST pixel (39.6 ± 6.2 mas) by 2020. If the lens system is observed directly in high-resolution images, then the brightness measurement of the lens leads to the precise calculation of the mass and distance to the lens system Batista et al 2015). But in the I band, the Figure 6.…”

OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

“…Based on the experience of Batista et al (2015), who resolved the equally bright source and lens of OGLE-2005-BLG-169 at a separation of ∼60 mas, we can see that such a measurement using present-day instrumentation would require a 15 year wait for a lens of M∼0.7 M e (M prim ∼0.48 M e ). From Figure 5 and Equation (13), this would imply only a 50% probability of separately resolving the source and lens.…”