The potential existence of a giant planet orbiting within a few AU of a stellar remnant has profound implications for both the survival and possible regeneration of planets during post-main sequence stellar evolution. This paper reports Hubble Space Telescope Fine Guidance Sensor and U.S. Naval Observatory relative astrometry of GD 66, a white dwarf thought to harbor a giant planet between 2 and 3 AU based on stellar pulsation arrival times. Combined with existing infrared data, the precision measurements here rule out all stellar-mass and brown dwarf companions, implying that only a planet remains plausible, if orbital motion is indeed the cause of the variations in pulsation timing.
@article{arxiv.1205.0806,
title = {Precision Astrometry of the Exoplanet Host Candidate GD 66},
author = {J. Farihi and J. P. Subasavage and E. P. Nelan and H. C. Harris and C. C. Dahn and J. Nordhaus and D. S. Spiegel},
journal= {arXiv preprint arXiv:1205.0806},
year = {2012}
}