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We summarize here results of our recent study of the relativistic stellar aberration requirements for the Space Interferometry Mission (SIM).
Picometer scale optical metrology specifications for the Space Interferometry Mission require precision calibration functions involving the optical and orientation characteristics of corner cube.
Here, we present the Dispersion Leverage Coronagraph (DLC), a variation of the Achromatic Interfero Coronagraph (AIC) that is designed for optical systems featuring large, dispersive primary objective gratings. DLC was originally designed for the Diffractive Interfero Coronagraph Exoplanet Resolver (DICER), a notional 20 m class infrared space telescope utilizing the enhanced one-dimensional angular resolution of large diffraction gratings to discover and characterize near-Earth exoplanets. Here we develop the theoretical foundation for DLC, and apply it to DICER as an example use case. We derive important properties of the DLC system, including focal plane transmission maps, stellar leakage, residual optical path difference tolerance, and pointing error/jitter considerations. Ultimately, we found that DLC effectively nulls an on-axis target across the entire spectrum in the focal plane, allowing for 2D/λ diffraction-limited imaging. It requires asymmetrical fine-guidance tolerances on pointing error/jitter. We work through a benchmark DICER design, explaining the need for a second disperser to reduce background from Zodiacal light, and showing that it could plausibly find and characterize ∼4 nearby, habitable exoplanets around Sun-like stars in a 7-year mission; about 30% of the habitable exoplanets within 8 pc were found in our simulation. The DLC may be useful for any application requiring extremely high-resolution, close companion spectroscopy.
The astronomic applications of non-military digital image processing are covered in this conference volume. Systems like CCD's, interactive data analysis facilities, stellar speckle interferometry, sky flux subsystems, guide star systems and various image processing systems are described. Techniques in photometry including filtering, automatic photometry, and image restoration are examined. Digital spectral analyses of galaxies, supernova remnants, stars and other celestial bodies are discussed together with algorithms developed to calibrate, clean up, enhance, and quantitatively analyze data. The techniques of image processing permit astronomers to make much more efficient use of their data for both subjective and quantitative analyses. Future missions, such as the Space Telescope, representing a vast data base are briefly covered.
We report on observations of the star 89 Her using the Palomar Testbed Interferometer (PTI) Our observations in the H and K band suggest the presence of a circumstellar dust shell. We discuss two observations in the context of simple models for 89 Her.
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Describes a metrology subsystem for NASA's Starlight mission, a space-based separated-spacecraft stellar interferometer.
In this paper we will discuss the techniques that are being used to make optical beam splitter especially the same-of-the-art splitters.
The Planet Detection Testbed is designed to simulate the architecture and operation of a space-borne four telescope nulling interferometer.
The Herbig Ae star HD139614 is a group-Ib object, which featureless SED indicates disk flaring and a possible pre-transitional evolutionary stage. We present mid- and near-IR interferometric results collected with MIDI, AMBER and PIONIER with the aim of constraining the spatial structure of the 0.1-10 AU disk region and assess its possible multi-component structure. A two-component disk model composed of an optically thin 2-AU wide inner disk and an outer temperature-gradient disk starting at 5.6 AU reproduces well the observations. This is an additional argument to the idea that group-I HAeBe inner disks could be already in the disk-clearing transient stage. HD139614 will become a prime target for mid-IR interferometric imaging with the second-generation instrument MATISSE of the VLTI.
Telescope Interferometer (LBTI) will survey nearby stars for faint exozodiacal dust (exozodi). This warm circumstellar dust, analogous to the interplanetary dust found in the vicinity of the Earth in our own system, is produced in comet breakups and asteroid collisions. Emission and or scattered light from the exozodi will be the major source of astrophysical noise for a future space telescope aimed at direct imaging and spectroscopy of terrestrial planets (exo- Earths) around nearby stars. About 20 of nearby field stars have cold dust coming from planetesimals at large distances from the stars (Eiroa et al. 2013, AA, 555, A11; Siercho et al. 2014, ApJ, 785, 33). Much less is known about exozodi; current detection limits for individual stars are at best 500 times our solar system's level (aka. 500 zodi). LBTI-HOSTS will be the first survey capable of measuring exozodi at the 10 zodi level (3). Detections of warm dust will also reveal new information about planetary system architectures and evolution. We will describe the motivation for the survey and progress on target selection, not only the actual stars likely to be observed by such a mission but also those whose observation will enable sensible extrapolations for stars that will not be observed with LBTI. We briefly describe the detection of the debris disk around Crv, which is the first scientific result from the LBTI coming from the commissioning of the instrument in December 2013, shortly after the first time the fringes were stabilized.
Optical interferometers are expected to provide the next great leap forward in space based astronomy beyond the Hubble Space Telescope. Various systems are envisioned, ranging from large orbiting structures to lunar based facilities to separated spacecraft flying in formation. Regardless of the specific architecture, these systems will present unprecedented challenges in the measurement and control of optical surfaces, hence driving the technological state-of-the-art in the areas of laser metrology and alignment and stabilization of optomechanical systems.
This paper describes the Micro-Precision Interferometer (MPI) testbed and its major achievements to date related to mitigating risk for future spaceborne optical interferometer missions.
The Orbiting Stellar Interferometer (OSI) is a proposed space-based observatory which will open exciting new vistas in astronomy and address fundamental scientific questions by making extremely accurate (3 - 30 microarcsecond) astrometric measurements of the positions of stars, quasars, and other astronomical objects as faint as magnitude 20. In addition, it will be able to image objects with a resolution of 5 milliarcseconds. As the first optical interferometer in space, OSI will provide major advances in astrophysics while demonstrating a powerful concept applicable to major space-based observations of the future. The Jet Propulsion Laboratory has developed a preliminary design of OSI to establish its feasibility and to estimate performance that can be achieved in a mission of moderate scale. In this first publication of the results of the first year of study, the science objectives are presented, and the design of the mission, instrument, and spacecraft are discussed.
The MASSIF (Masses and Stellar Systems with Interferometry) Team will use SIM to investigate the mass content of the Galaxy - from huge stars to barely glimmering brown dwarfs, and from hot white dwarfs to exotic black holes. We will target various samples of the Galactic population to determine and relate the fundamental characteristics of mass, luminosity, age, composition, and multiplicity - attributes that together yield an extensive understanding of the stars. Our samples will include distant clusters that span a factor of 5000 in age, and commonplace stars and substellar objects that lurk near the Sun. The principal goals of the MASSIF Key Project are to (1) define the mass-luminosity relation for main sequence stars in five fundamental clusters so that effects of age and metallicity can be mapped (Trapezium, TW Hydrae, Pleiades, Hyades, and M67), and (2) determine accurate masses for representative examples of nearly every type of star, stellar descendant or brown dwarf in the Galaxy.
Diameters are reported for four late-type giant stars, alpha Boo, alpha Ori, alpha Tau, and beta Peg. The diameters were obtained with a new kind of interferometer designed expressly to operate in the presence of atmospheric fluctuations. The new technique, called amplitude interferometry, is briefly described. The results include measurements of alpha Ori at several wavelengths.