The Gould's Belt Distances Survey is a large project aimed at measuring the distance to several hundred young stars in the most prominent star-forming regions within about 500 pc of the Sun (mostly Ophiuchus, Taurus, Perseus, Serpens, and Orion, but also Monoceros or Cepheus). The distances are obtained from direct trigonometric parallax measurements based on multi-epoch observations collected over periods of one-and-a-half to three years. The observations are obtained using the Very Long Baseline Interferometry technique, whereby radio telescopes separated by thousands of kilometers are used in combination to reconstruct images with an angular resolution of order one milli-arcsecond. By carefully calibrating this type of data, the position of radio sources, and their trigonometric parallax, can be measured to an accuracy of about 50 micro-arcseconds. This corresponds to relative accuracies of 0.5% for sources at 100 pc, 1.5% for sources at 300 pc, and 2.5% for sources at 500 pc.

The Gould's Belt Distances Survey is an observatory-wide project that makes use of three instruments currently operated by the National Radio Astronomy Observatory. The Karl G. Jansky Very Large Array is used to identify targets across the five regions of interests. The Very Long Baseline Array is then used (often in conjunction with the Green Bank Telescope) to measure the position of the targets at 6 epochs over the course of one-and-a-half to three years, and determine their trigonometric parallax.

The main output of this project is a list of sources with measured trigonometric parallaxes. The survey is on-going and expected to be complete by about 2015. We will post the results as we proceed, so please, keep visiting this web page for updates. If you have any question regarding the survey, or if your favorite young star is not in the list, please send us a message (