The NANOGrav 11-year Data Set: Constraints on Planetary Masses Around 45 Millisecond Pulsars

TL;DR

This study uses 11 years of pulsar timing data to set upper limits on the masses of potential exoplanets around millisecond pulsars, achieving sensitivity down to lunar masses but detecting none.

Contribution

It provides the first comprehensive constraints on planetary masses around millisecond pulsars using long-term pulsar timing data.

Findings

No exoplanets detected around the 45 pulsars.

Sensitivity to planetary masses as low as the Moon.

Constraints on planetary masses as a function of orbital period.

Abstract

We search for extrasolar planets around millisecond pulsars using pulsar timing data and seek to determine the minimum detectable planetary masses as a function of orbital period. Using the 11-year data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), we look for variations from our models of pulse arrival times due to the presence of exoplanets. No planets are detected around the millisecond pulsars in the NANOGrav 11-year data set, but taking into consideration the noise levels of each pulsar and the sampling rate of our observations, we develop limits that show we are sensitive to planetary masses as low as that of the moon. We analyzed potential planet periods, P, in the range 7 days < P < 2000 days, with somewhat smaller ranges for some binary pulsars. The planetary mass limit for our median-sensitivity pulsar within this period range is 1 M_moon (P / 100 days)^(-2/3).