Discovery of a bright microlensing event with planetary features towards the Taurus region: a super Earth planet

TL;DR

This paper reports the discovery of a microlensing event in the Taurus region that reveals a binary lens system hosting a super Earth planet approximately 9 Earth masses, using high-cadence observations and detailed modeling.

Contribution

First detection of a planetary microlensing event in the Taurus region with detailed characterization of a super Earth planet and the lens system.

Findings

Identification of a super Earth planet with ~9 Earth masses.

Closest lens system at ~380 pc with a mass of ~0.25 solar masses.

Binary lens system with very low mass ratio components.

Abstract

The transient event labeled as TCP J05074264+2447555 recently discovered towards the Taurus region was quickly recognized to be an ongoing microlensing event on a source located at distance of only $700-800$ pc from Earth. Here, we show that observations with high sampling rate close to the time of maximum magnification revealed features that imply the presence of a binary lens system with very low mass ratio components. We present a complete description of the binary lens system which hosts an Earth-like planet with most likely mass of $9.2\pm 6.6$ M$_{\oplus}$. Furthermore, the source estimated location and detailed Monte Carlo simulations allowed us to classify the event as due to the closest lens system, being at a distance of $\simeq 380$ pc and mass $\simeq 0.25$ M$_{\odot}$.