Science with the Keck Interferometer ASTRA Program

Abstract

The ASTrometric and phase-Referenced Astronomy (ASTRA) project will provide phase referencing and astrometric observations at the Keck Interferometer, leading to enhanced sensitivity and the ability to monitor orbits at an accuracy level of 30-100 microarcseconds. Here we discuss recent scientific results from ASTRA, and describe new scientific programs that will begin in 2010-2011. We begin with results from the "self phase referencing" (SPR) mode of ASTRA, which uses continuum light to correct atmospheric phase variations and produce a phase-stabilized channel for spectroscopy. We have observed a number of protoplanetary disks using SPR and a grism providing a spectral dispersion of ~2000. In our data we spatially resolve emission from dust as well as gas. Hydrogen line emission is spectrally resolved, allowing differential phase measurements across the emission line that constrain the relative centroids of different velocity components at the 10 microarcsecond level. In the upcoming year, we will begin dual-field phase referencing (DFPR) measurements of the Galactic Center and a number of exoplanet systems. These observations will, in part, serve as precursors to astrometric monitoring of stellar orbits in the Galactic Center and stellar wobbles of exoplanet host stars. We describe the design of several scientific investigations capitalizing on the upcoming phase-referencing and astrometric capabilities of ASTRA.

Published in the proceedings of the SPIE 2010 conference on "Optical and Infrared Interferometry II"

References in corpus (6)

• The origin of hydrogen line emission for five Herbig Ae/Be stars spatially resolved by VLTI/AMBER spectro-interferometry
• Spectrally Dispersed K-Band Interferometric Observations of Herbig Ae/Be Sources: Inner Disk Temperature Profiles
• Spatially and Spectrally Resolved Hydrogen Gas within 0.1 AU of T Tauri and Herbig Ae/Be Stars
• Constraining the wind launching region in Herbig Ae stars: AMBER/VLTI spectroscopy of HD104237
• Water vapour and hydrogen in the terrestrial-planet-forming region of a protoplanetary disk
• Spatially resolving the hot CO around the young Be star 51 Ophiuchi

Cited by in corpus (6)

• Slowly-Rotating Black Holes in Einstein-Dilaton-Gauss-Bonnet Gravity: Quadratic Order in Spin Solutions
• Testing the black hole no-hair theorem at the galactic center: Perturbing effects of stars in the surrounding cluster
• Holographic Imaging of Crowded Fields: High Angular Resolution Imaging with Excellent Quality at Very Low Cost
• ASTRA: ASTrometry and phase-Referencing Astronomy on the Keck interferometer
• Resolving the Sub-AU-Scale Gas and Dust Distribution in FU Orionis Sources
• Radio & Optical Interferometry: Basic Observing Techniques and Data Analysis