An international team of astronomers has released a massive dataset detailing the characteristics of over 1,600 "neighborhood" stars, in an effort to involve the public in the ongoing effort to discover nearby exoplanets. The catalog has already led to the detection of over 100 potential exoplanets, alongside the confirmed discovery of an alien world in orbit around the fourth closest star to our Sun.
The observations of 1,624 stars, all of which sit within 100 parsecs (325 light years) of Earth, were made using the High Resolution Echelle Spectrometer (HIRES) instrument mounted on the W.M. Keck Observatory's 10-m (33-ft) telescope located atop Mauna Kea, Hawaii.
HIRES is a cutting-edge spectrometer, capable of splitting a star's light into thousands of color channels. By measuring the intensity of these channels, or wavelengths, scientists can gain significant insights regarding, for example, a stellar body's composition and movement patterns.
The new release is comprised of 60,949 individual observations, with exposures ranging from 30 seconds to 20 minutes in duration. Not all of the stars were subjected to the same level of scrutiny by HIRES, meaning that some stellar bodies will have only several days' worth of data, whereas others have decades.
"[HIRES] wasn't specifically optimized to look for exoplanets," Burt says. "It was designed to look at faint galaxies and quasars. However, even before HIRES was installed, our team worked out a technique for making HIRES an effective exoplanet hunter."
Scientists have discovered that by looking at HIRES' intricate breakdown of a star's light, they could measure a star's radial velocity and look for subtle variations in the movement of the star that could result from the gravitational influence of an orbiting exoplanet.
An initial analysis carried out by the team is already yielding a promising number of exoplanets. Already, the team has discovered roughly 100 potential exoplanets, six of which are believed to exist around a single star.
Thanks to the data collected by HIRES, the researchers have also been able to confirm the presence of an exoplanet in orbit around the fourth-closest star to our Sun, GJ 411. The exoplanet is believed to orbit very close to its parent star, which boasts a mass of 40 percent of our Sun. The proximity means that the alien world completes a lap of GJ 411 once every 10 days.
Periodically, the team will supplement the dataset with further observations made by HIRES. It is hoped that astronomers around the world will use the HIRES resource to advance their own observations, or as a leaping off point for new imaging campaigns. However, the data is not meant for the sole use of professionals.
"One of our key goals in this paper is to democratize the search for planets," explained team member Greg Laughlin of Yale. "Anyone can download the velocities published on our website and use the open source Systemic software package and try fitting planets from the data."
The paper containing details on the dataset is due to be published in the Astrophysical Journal.