Recently, associate research fellow of Xinjiang Astronomical Observatory, J. B. Wang, gained the reference frame tie between the solar system ephemerides and international celestial reference frame (ICRF) for the first time, by using data sets of multiple pulsars from the Nanshan 25m telescope and the Parkes 64m telescope, and combined the VLBI data of published work. This work has been accepted for publication by MNRAS.

At present, the solar system ephemerides that published by U.S. Jet Propulsion Laboratory has been widely used. A statistically significant change in the obliquity of the ecliptic ~ 2 milli-arc second is found for the JPL ephemeris DE405. J.B. Wang showed the precision of frame tie is better than 1 milli-arc second. The researchers improved the research methods , and find that the timing positions differ significantly from the VLBI positions.

The reference frame is the foundation of astrometry and plays an important role in astronomical research. Reference frame tie can be used to determine the obliquity of ecliptic and its rate of change and test the solar system ephemerides and study the dynamic of solar dynamics in inertial frame. In addition, it is important for spacecraft navigation, gravitational wave searches and searches for unknown solar-system bodies.

Article link: http://dx.doi.org/10.1093/mnras/stx837