Notre Dame astrophysicist determines occurrence rate of giant planets around M-dwarfs | News | Notre Dame News | University of Notre Dame Skip To Content Skip To Navigation Skip To Search University of Notre Dame Notre Dame News Experts ND in the News Subscribe About Us Home Contact Search Menu Home › News › Notre Dame astrophysicist determines occurrence rate of giant planets around M-dwarfs Notre Dame astrophysicist determines occurrence rate of giant planets around M-dwarfs Published: July 26, 2013 Author: Gene Stowe Justin Crepp A study led by Notre Dame astrophysicist Justin Crepp has for the first time definitively determined how many of the lowest-mass stars in the galaxy host gas giant planets. The researchers’ paper, “The Occurrence Rate of Giant Planets around M-dwarfs,” was posted to arXiv this week and submitted for publication in the Astrophysical Journal. The group used ground-based imaging observations in combination with the Doppler radial velocity method to determine that 6.5 percent of low-mass stars, the so-called “M-dwarfs,” have planets located within 20 astronomical units, including the outer regions where researchers previously could not access. “We have invented a new technique that allows us to peer beyond the orbits normally accessible to previous observations, thus taking a much-needed shortcut to the answer,” Crepp said. “Our results show that low-mass stars form few planets similar to Jupiter, most likely because compared to Sun-like stars, low-mass stars have less material — circumstellar building blocks, if you will — to start with.” Crepp, principal investigator for the NASA-funded high-contrast imaging program, co-authored the paper with Benjamin Montet, a graduate student at Caltech whom he co-advises, John Asher Johnson, Andrew W. Howard and Geoffrey W. Marcy. Since the first extrasolar planet was discovered in 1995, researchers have identified planets located within 4 astronomical units of stars by carefully monitoring the gravitational “wobble” induced upon the star as the planet orbits. That movement typically creates a measurable periodic signal. In cases where the observations reveal a straight line, or systematic “trend,” researchers suspect they are mapping only a fraction of the signal created by a more distant object with a much longer orbital period. Montet and Crepp obtained images to identify such planets using a sample of 111 M-stars. The results are consistent with the rates found by another technique, called gravitational microlensing, which detects orbiting planets when they pass between Earth and a background star. Such events are rare and not repeated, making follow-up observations challenging. Three-fourths of all stars are M-dwarfs. The group plans to conduct a similar survey of stars at the next mass-level, the “K-dwarfs,” just one below that of the Sun, in order to continue a methodical investigation that quantifies the occurrence rate of gas giant worlds around different types of stars. While the study showed that 1 in 16 of the lowest-mass stars have gas giants, Crepp expects to find more around more-massive targets. “We expect that number to increase,” he said. “We think that bigger stars have a propensity to form more massive planets.” Contact: Justin Crepp, 574-631-4092, jcrepp@nd.edu Posted In: Research Home Experts ND in the News Subscribe About Us Related October 05, 2022 Astrophysicists find evidence for the presence of the first stars October 04, 2022 NIH awards $4 million grant to psychologists researching suicide prevention September 29, 2022 Notre Dame, Ukrainian Catholic University launch three new research grants September 27, 2022 Notre Dame, Trinity College Dublin engineers join to advance novel treatment for cystic fibrosis September 22, 2022 Climate-prepared countries are losing ground, latest ND-GAIN index shows For the Media Contact Office of Public Affairs and Communications Notre Dame News 500 Grace Hall Notre Dame, IN 46556 USA Facebook Twitter Instagram YouTube Pinterest © 2022 University of Notre Dame Search Mobile App News Events Visit Accessibility Facebook Twitter Instagram YouTube LinkedIn