Differential Astrometry of Sub-arcsecond Scale Binaries at the Palomar Testbed Interferometer

Abstract

We have used the Palomar Testbed Interferometer to perform very high precision differential astrometry on the 0.25 arcsecond separation binary star HD 171779. In 70 minutes of observation we achieve a measurement uncertainty of approximately 9 micro-arcseconds in one axis, consistent with theoretical expectations. Night-to-night repeatability over four nights is at the level of 16 micro-arcseconds. This method of very-narrow-angle astrometry may be extremely useful for searching for planets with masses as small as 0.5 Jupiter Masses around a previously neglected class of stars -- so-called ``speckle binaries.'' It will also provide measurements of stellar parameters such as masses and distances, useful for constraining stellar models at the 10^-3 level.

19 pages including 6 figures. Submitted to ApJ. Typos corrected, several parts reworded for clarification

References in corpus (2)

• A Mass for the Extrasolar Planet Gl 876b Determined from Hubble Space Telescope Fine Guidance Sensor 3 Astrometry and High-Precision Radial Velocities
• Visual orbit for the low-mass binary Gliese 22 AC from speckle interferometry

Cited by in corpus (29)

• First Light for GRAVITY: Phase Referencing Optical Interferometry for the Very Large Telescope Interferometer
• Separated Fringe Packet Observations with the CHARA Array II: $\omega$ Andromeda, HD 178911, and ξ Cephei
• Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
• The PHASES Differential Astrometry Data Archive. V. Candidate Substellar Companions to Binary Systems
• Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review
• Impact of Stellar Dynamics on the Frequency of Giant Planets in Close Binaries
• Atmospheric scintillation at Dome C, Antarctica: implications for photometry and astrometry
• Masses, Luminosities, and Orbital Coplanarities of the mu Orionis Quadruple Star System from PHASES Differential Astrometry
• Precision multi-epoch astrometry with VLT cameras FORS1/2
• The PHASES Differential Astrometry Data Archive. I. Measurements and Description
• PHASES Differential Astrometry and the Mutual Inclination of the V819 Herculis Triple Star System
• The Anisoplanatic Point Spread Function in Adaptive Optics
• Detection and Characterization of Planets in Binary and Multiple Systems
• PHASES Differential Astrometry and Iodine Cell Radial Velocities of the kappa Pegasi Triple Star System
• PHASES High Precision Differential Astrometry of delta Equulei
• The orbits of the quadruple star system 88 Tau A from PHASES differential astrometry and radial velocity
• The PRIMA fringe sensor unit
• Limits to Tertiary Astrometric Companions in Binary Systems
• Detection and Characterization of Planetary Systems with $\mu$as Astrometry
• High-precision astrometry on the VLT/FORS1 at time scales of few days
• Comparison of fringe-tracking algorithms for single-mode near-infrared long-baseline interferometers
• The PHASES Differential Astrometry Data Archive IV: The Triple Star Systems 63 Gem A and HR 2896
• Precision Astrometry of a Sample of Speckle Binaries and Multiples with the Adaptive Optics Facilities at the Hale and Keck II Telescopes
• The PHASES Differential Astrometry Data Archive. III. Limits to Tertiary Companions
• The Origins of the Substellar Companion to GQ Lup
• Prospects for detecting the astrometric signature of Barnard's Star b
• Observation of double star by long-baseline interferometry
• Simulating a dual beam combiner at SUSI for narrow-angle astrometry
• The PHASES Differential Astrometry Data Archive. II. Updated Binary Star Orbits and a Long Period Eclipsing Binary