THE EXO-ZODIACAL DISK MAPPER: A SPACE INTERFEROMETER TO DETECT AND MAP ZODIACAL DUST DISKS AROUND NEARBY STARS P. BÉLY 1,∗ , L. PETRO 1 , R. BURG 2 , L. WADE 3 , C. BEICHMAN 3 , J. GAY 4 , P. BAUDOZ 4 , Y. RABBIA 4 and J.-M. PERRIN 5 1 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A. 2 Johns Hopkins University, Baltimore, MD, 21218, U.S.A. 3 Jet Propulsion Laboratory, Pasadena, CA, 91109, U.S.A. 4 Observatoire de la Côte d’Azur, Caussols, France 5 Observatoire de Haute Provence, St. Michel, France ( ∗ Author for all correspondence, e-mail: bely@stsci.edu) (Received 3 June 1998; accepted 8 February, 1999) Abstract. We present a concept for a space mission designed to make a mid-IR survey of poten- tial zodiacal dust disks around nearby stars. We show that a two-aperture (0.6 m diameter), 10-m baseline, nulling interferometer located in a 1 × 4 AU, 4-yr solar orbit would allow for the survey of 400 stars in the solar neighborhood and permit a first-order determination of the disk inclination and radial dependences of density and temperature. The high dynamic range of the instrument may also be used to study additional astrophysical phenomena. Beyond its own scientific merit, such a mission would serve as a technological precursor to a larger interferometer of the type being considered for the detection of earth-like planets. Keywords: Circumstellar disks, Coronagraph, Space telescopes, Zodiacal dust disks 1. Introduction The direct detection and characterization of earth-like planets is one of the main goals of the NASA Origins program. A keystone mission of that program, the ‘Terrestrial Planet Finder Array,’ or TPFA, is a large nulling interferometer which in its current design consists of four 1.5-m telescopes on a 70–100-m baseline (Beichman, 1996). However, a number of scientific and technical achievements must be accomplished before such a major instrument can be built. Among the most significant scientific questions that need to be answered is the existence, intensity, and orientation of potential zodiacal dust disks in candidate extra-solar systems. The luminosity of the dust in the inner 10 AU of the Solar System is of order 10 −7 L ⊙ , whereas the luminosity of Earth is 5 × 10 −10 L ⊙ . In the mid-infrared, at 10 µm the flux of the Zodiacal Dust is F ZD ≃ 1 × 10 −4 R ⊙ and the flux of Earth is F ⊕ = 5 × 10 −7 F ⊙ . Therefore, whether in the visible or in the infrared, methods for the detection of extra-solar planets have to contend not only with the glare of the adjacent star, but also with that of the enveloping zodiacal dust. Nulling Experimental Astronomy 9: 189–204, 1999. © 1999 Kluwer Academic Publishers. Printed in the Netherlands.