Super-Nyquist Asteroseismology with Future Space Missions

TL;DR

This paper introduces a novel photometric technique for future space missions that mitigates Nyquist aliasing by using periodic sampling modulation, enhancing the accuracy of stellar oscillation measurements.

Contribution

It presents a new method involving periodic sampling modulation and a division of long exposures to distinguish true signals from aliases, validated analytically and through simulations.

Findings

Method effectively separates true frequencies from aliases.

Dividing long exposures preserves amplitude spectra.

Proposed approach benefits PLATO mission's asteroseismology capabilities.

Abstract

We propose a photometric technique for future space missions that overcomes the problem of Nyquist aliases. These aliases result from typically long cadences of observation imposed by telemetry constraints. The proposed method is to introduce a periodic modulation to the sampling rate. Suitable combinations of the frequency and the amplitude of this modulation allow the true peaks to be distinguished from the aliases. We provide an analytical proof of the validity of this method and some demonstrations with simulated data. We also propose to divide a long cadence into two unequal parts, aiming at reproducing the intrinsic amplitude spectrum of stars without a severe smearing effect due to long exposures. The two exposures can be summed to recover the photon statistics if the user is interested in doing so. Based on these proposals, a specific recommendation for the PLATO mission is made to maximise its capability of photometry for asteroseismology, without serious interference with its other scientific missions.