Penn telescope hunts for planets orbiting small, dim stars

Penn astronomers are celebrating the dedication of a new planet-hunting telescope known as Minerva-Red. Installed at the Fred Lawrence Whipple Observatory in Arizona, Minerva-Red is part of the Minerva project, an array of low-cost telescopes that are designed to discover planets orbiting stars other than the sun.

Thousands of potential exoplanets have been identified, the vast majority within the past five years. New telescopes and instruments are increasingly capable of detecting rocky, Earth-like planets, with astronomers around the world hoping to be the first to find the chemical signatures of life in their atmospheres.  


In Minerva’s search, Cullen Blake, an associate professor in the Department of Physics & Astronomy in the School of Arts & Sciences, along with graduate student David Sliski, join astronomers from Harvard University, the University of New South Wales, the University of Montana, the Smithsonian Institution, and Pennsylvania State University to operate five robotic telescopes. 

Penn’s Minerva-Red telescope has special capabilities that make it well-suited for finding planets orbiting some of Earth’s nearest stellar neighbors. The “Red” in the name is what sets it apart from the other telescopes in the project; it is designed to look for planets around low-mass stars, light from which is mostly in the infrared part of the spectrum.

“Over the last 20 years,” Blake says, “the pace of discovery in terms of finding planets around other stars has been incredible. But most of those efforts have been focused on finding planets around stars that are broadly like the sun. The sun isn’t an unusual star, but most stars are much smaller and much cooler than it is.”

Sliski says that if one were to make a list of the sun’s 100 nearest stellar neighbors, “many of them are small stars and we essentially don’t know anything about the planetary systems most of them might have. Over the last few years, however, we’ve seen some tantalizing results that suggest that these types of stars might have a lot of planets.”

The search for planets similar to Earth has historically focused on sun-like stars—but smaller, cooler stars could also host potentially habitable worlds. Even though there are many such stars in Earth’s proverbial backyard, their dimness has limited astronomers’ ability to detect and study their planets.  

A telescope specifically matched to the traits of those small stars has several advantages. Because it will focus on a specific sample of some of the closest small stars, Minerva-Red is much less expensive than the ground- and space-based telescopes currently used in the hunt for exoplanets.    

“The telescope is essentially the biggest amateur telescope you can get,” Sliski says, “and the data-collecting instrument is custom-built, almost entirely out of parts you can order from a catalog. That really cuts down on costs and time, and makes it easier for other groups to replicate our work.”

Working within the larger ecosystem of planet-hunters, telescopes like Minerva-Red can help astronomers pick the best targets for future studies with larger telescopes, as well as follow up others’ discoveries.

“There’s going to be a ton of work for different telescopes to do, and small telescopes like Minerva-Red will be able to make big contributions,” Blake says.