Towards a Small Prototype Planet Finding Interferometer: The next step in planet finding and characterization in the infrared

TL;DR

This paper advocates for a small, cost-effective infrared interferometer, SPPFI, to detect and characterize exoplanets and other astronomical phenomena, as a practical step before large-scale missions.

Contribution

It proposes the SPPFI mission concept as a feasible, intermediate step for exoplanet detection and characterization in the infrared, addressing current technological and budget constraints.

Findings

SPPFI can characterize atmospheres of non-transiting exoplanets.

It can image debris disks and active galactic nuclei.

The mission cost is estimated at $600-800 million.

Abstract

During the last few years, considerable effort has been directed towards large-scale (>> $1 Billion US) missions to detect and characterize earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin missions. However, technological and budgetary issues as well as shifting science priorities will likely prevent these missions from entering Phase A until the next decade. The secondary eclipse technique using the Spitzer Space Telescope has been used to directly measure the temperature and emission spectrum of extrasolar planets. However, only a small fraction of known extrasolar planets are in transiting orbits. Thus, a simplified nulling interferometer, which produces an artificial eclipse or occultation, and operates in the near- to mid-infrared (e.g. ~ 3 to 8 or 10 microns), can characterize the atmospheres of this much larger sample of the known but non-transiting exoplanets. Many other scientific problems can be addressed with a system like this, including imaging debris disks, active galactic nuclei, and low mass companions around nearby stars. We discuss the rationale for a probe-scale mission in the $600-800 Million range, which we name here as the Small Prototype Planet Finding Interferometer (SPPFI).