Twenty Years of Precise Radial Velocities at Keck and Lick Observatories

Twenty Years of Precise Radial Velocities at Keck and Lick Observatories

Authors:

Wright et al

Abstract:

The precise radial velocity survey at Keck Observatory began over 20 years ago. Its survey of thousands of stars now has the time baseline to be sensitive to planets with decade-long orbits, including Jupiter analogs. I present several newly-finished orbital solutions for long-period giant planets. Although hot Jupiters are generally "lonely" (i.e. they are not part of multiplanet systems), those that are not appear to often have giant companions at 5 AU or beyond. I present two of the highest period- ratios among planets in a two-planet system, and some of the longest orbital periods ever measured for exoplanets. In many cases, combining Keck radial velocities from those from other long-term surveys at Lick Observatory, McDonald Observatory, HARPS, and, of course, OHP spectrographs, produces superior orbital fits, constraining both period and eccentricity better than could be possible with any single set alone. Stellar magnetic activity cycles can masquerade as long-period planets. In most cases this effect is very small, but a loud minority of stars, including, apparently, HD 154345, show very strong RV-activity correlations.

The Breakthrough Listen Project has Started its SETI Efforts

The first batch of data from a US$100 million effort to find signs of intelligent life beyond Earth has been released for public access. The Breakthrough Listen Initiative began making observations in January using the Green Bank Radio Telescope in West Virginia and Lick Observatory's Automated Planet Finder in California, and has posted what it's gathered so far on its website.

link.

Lick Observatory Automated Planet Finder Tested Against HD 185144 and HD 9407

APF - The Lick Observatory Automated Planet Finder

Authors:

Vogt et al

Abstract:

The Automated Planet Finder (APF) is a facility purpose-built for the discovery and characterization of extrasolar planets through high-cadence Doppler velocimetry of the reflex barycentric accelerations of their host stars. Located atop Mt. Hamilton, the APF facility consists of a 2.4-m telescope and its Levy spectrometer, an optical echelle spectrometer optimized for precision Doppler velocimetry. APF features a fixed format spectral range from 374 nm - 970 nm, and delivers a "Throughput" (resolution * slit width product) of 114,000 arc-seconds, with spectral resolutions up to 150,000. Overall system efficiency (fraction of photons incident on the primary mirror that are detected by the science CCD) on blaze at 560 nm in planet-hunting mode is 15%. First-light tests on the RV standard stars HD 185144 and HD 9407 demonstrate sub-meter per second precision (RMS per observation) held over a 3-month period. This paper reviews the basic features of the telescope, dome, and spectrometer, and gives a brief summary of first-light performance.