The First Extrasolar Planet Discovered with A New Generation High Throughput Doppler Instrument

We report the first extrasolar planet, ET1, detected with a new generation Doppler instrument, called Exoplanet Tracker. This planet has a minimum mass of 0.41 Jupiter masses and orbits a V = 8.1 K0V star with a 4.8 day period. The planet was identified using the KPNO Coude Feed 0.9 meter telescope in spring 2005. This is the first time an extrasolar planet around a star fainter than V=8 magnitude has been discovered with an under 1 meter size astronomical telescope and Doppler instrument. This planet discovery is possible due to the extremely high throughput of the instrument, nearly 50% measured from the fiber output end to the detector.

This discovery enables a new generation radial-velocity survey that could detect thousands of exoplanets using multiple-object versions of the ET instruments, called the W.M. Keck Exoplanet Tracker, at large wide-field telescopes in 2006-2020. A prototype multiple object ET has already demonstrated a 25 object capability for precision Doppler measurements at the Sloan telescope in early 2005. The ET instrument design is based on dispersed fixed-delay interferometry (Ge 2002), which is evolved from the earlier externally dispersed interferometry (Erskine and Ge 2000; Ge, Erskine and Rushford 2002) and the Global Oscillation Net Work (GONG) interferometry (Barker & Hollenbach 1972; Gorskii & Lebedev 1977; Beckers & Brown 1978; Harvey et al., 1988; Harvey 2002 private communications).

We acknowledge the excellent support from the KPNO and Sloan management, technical and observational staff. The ET project is supported by the University of Florida, NSF, Keck Foundation and NASA JPL (Michelson Fellowship Program).