Finding Exoplanets: How to Take the Galactic Census
On the hunt for still undiscovered exoplanets?
Take note that a research team has put together a set of directions, pointers to help find planets around other stars.
Lowell Observatory astronomer Evgenya Shkolnik and her collaborators have examined new and existing data from stars and brown dwarfs that are less than 300 million years old.
In all, Shkolnik and colleagues identified 144 young targets for exoplanet searches, with 20 very strong candidates.
Their work is based on sifting through data of about 8,700 stars within 100 light years of the Sun to find these candidates. The spectra were collected using two Hawaiian Mauna Kea telescopes (Keck and the Canada-France-Hawaii telescopes).
Distances to the stars were measured by Guillem Anglada-Escude (Universität Göttingen) using the du Pont telescope in Chile, operated by the Carnegie Institution for Science.
Markers in spectroscopic data
Reporting in The Astrophysical Journal, the scientists note that by looking for markers in spectroscopic data and measuring the motions of the stars, they were able to carefully examine the age of each stars.
Since low-mass stars are small and dim, they are good candidates for directly imaging planets around them. And young stars make it even easier since the young planet is still hot and bright. Plus, knowing the planetary system’s age allows for the characterization of the planet itself beyond the initial detection.
“Since low-mass stars are the most common type of star in our galaxy, most planets probably reside in these environments,” said graduate student Brendan Bowler at the Institute for Astronomy, University of Hawai‘i. “Finding young versions of these stars to search for planets is fundamental to understanding the galactic census of exoplanets.”
“These young stars help point the way. And if the Jupiter-mass planets are there, we will find them,” added Shkolnik in a Nov. 12 Lowell Observatory press release. The observatory is located in Flagstaff, Arizona.
Those 20 very strong candidates are being inspected for planets using Gemini’s NICI Planet-Finding Campaign and the Planets Around Low-Mass Stars survey. That work is being led by astronomer Michael Liu and Bowler, both at the Institute for Astronomy, University of Hawai‘i.
By Leonard David via Lowell Observatory