OGLE-2017-BLG-1434Lb: Confirmation of a Cold Super-Earth using Keck Adaptive Optics

TL;DR

This paper confirms the existence of a cold super-Earth exoplanet through microlensing observations and adaptive optics, providing detailed mass and distance measurements that support the planet's classification and its position near the planet-host mass ratio power law.

Contribution

The study uses Keck adaptive optics to precisely measure the lens star's flux, confirming the super-Earth nature of OGLE-2017-BLG-1434 and refining its physical parameters.

Findings

Confirmed the super-Earth with mass 4.43 M⊕

Determined the lens star's mass and distance accurately

Located the system near the inflection point of the mass-ratio power law

Abstract

The microlensing event OGLE-2017-BLG-1434 features a cold super-Earth planet which is one of eleven microlensing planets with a planet-host star mass ratio $q < 1 \times 10^{-4}$. We provide an additional mass-distance constraint on the lens host using near-infrared adaptive optics photometry from Keck/NIRC2. We are able to determine a flux excess of $K_L = 16.96 \pm 0.11$ which most likely comes entirely from the lens star. Combining this with constraints from the large Einstein ring radius, $\theta_E=1.40 \pm 0.09\;mas$ and OGLE parallax we confirm this event as a super-Earth with mass $m_p = 4.43 \pm 0.25M_\odot$. This system lies at a distance of $D_L = 0.86 \pm 0.05\,kpc$ from Earth and the lens star has a mass of $M_L=0.234\pm0.012M_\odot$. We confirm that with a star-planet mass ratio of $q=0.57 \times 10^{-4}$, OGLE-2017-BLG-1434 lies near the inflexion point of the planet-host mass-ratio power law.