Detection of Exoplanets in M31 with Pixel-Lensing: The Event Pa-99-N2 Case

TL;DR

This paper demonstrates the potential for detecting exoplanets in the M31 galaxy through pixel-lensing during microlensing events, highlighting the method's sensitivity to small mass planets with high-cadence observations.

Contribution

It introduces a novel application of pixel-lensing to detect exoplanets in M31 and reanalyzes a specific microlensing event to assess planetary deviation detectability.

Findings

Exoplanets with about 2 Jupiter masses are detectable in M31.

Small mass exoplanets (<20 Earth masses) can cause observable deviations.

Long duration, bright microlensing events enhance detection efficiency.

Abstract

We show that exoplanets in the M31 galaxy may be detected with the pixel-lensing method by using telescopes making high cadence observations of an ongoing microlensing event. Although the mean mass for detectable exoplanets is about $2 M_{\rm {J}}$, even small mass exoplanets ($M_{\rm P} < 20 M_{\oplus}$) can cause significant deviations, which are observable with large telescopes. We reanalysed the POINT-AGAPE microlensing event PA-99-N2. First, we test the robustness of the binary lens conclusion for this light curve. Second, we show that for such long duration and bright microlensing events, the efficiency for finding planetary-like deviations is strongly enhanced.