Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology .
With an angular separation of only 35 mas ( or 0.05 AU ) from its host star , Proxima b is however hardly observable with current imaging telescopes and future space-based coronagraphs .
One way to separate the photons of the planet from those of its host star is to use an interferometer that can easily resolve such spatial scales .
In addition , its proximity to Earth and its favorable contrast ratio compared with its host M dwarf ( approximately 10 ^ { -5 } at 10 microns ) makes it an ideal target for a space-based nulling interferometer with relatively small apertures .
In this paper , we present the motivation for observing this planet in the mid-infrared ( 5-20 microns ) and the corresponding technological challenges .
Then , we describe the concept of a space-based infrared interferometer with relatively small ( < 1m in diameter ) apertures that can measure key details of Proxima b , such as its size , temperature , climate structure , as well as the presence of important atmospheric molecules such as H _ { 2 } O , CO _ { 2 } , O _ { 3 } , and CH _ { 4 } .
Finally , we illustrate the concept by showing realistic observations using synthetic spectra of Proxima b computed with coupled climate chemistry models .