Astronomers using the Gemini Planet Imager instrument at the Gemini South telescope in Chile have imaged a sample of 44 bright Herbig Ae/Be and T-Tauri stars in near-infrared light. They’ve detected dusty planet-forming disks around 80% of the targeted stars and point-like companions for 47% of these targets, including 3 brown dwarfs (two confirmed and one new) and a super-Jupiter planet candidate.
Planets form in disks of gas and dust that encircle young stars just a few million years old.
The Gemini Planet Imager (GPI) is one of a few instruments in the world capable of resolving these disks.
Previous observations have indicated that rings, made of large and small dust grains as well as gas, are often seen in these disks.
Exactly what creates these rings is uncertain, but they have been attributed to newborn planets interacting with the disk.
As part of the Gemini-Large Imaging with GPI Herbig/T-Tauri Survey (Gemini-LIGHTS), University of Michigan astronomer Evan Rich and colleagues produced high-resolution images of 44 bright Herbig Ae/Be and T-Tauri stars.
“We want to answer the fundamental question of how planets form,” Dr. Rich said.
“In particular, the Gemini-LIGHTS survey concentrates on stars that are more massive than the Sun to investigate the influence that a parent star’s mass might have on the planet-formation process.”
Using the GPI instrument, the researchers detected disks around 80% of the 44 targeted stars, and also found one new candidate planet — around V1295 Aquilae — and three brown dwarfs.
Two of the brown dwarfs — around V921 Sco and HD 158643 — had already been identified as candidates by earlier observations and which have now been confirmed through these observations.
The third brown dwarf, around the star HD 101412, is a new candidate.
The survey’s key finding, however, is that the disks appear to behave differently depending upon the mass of the star they are circling.
“Systems with small dust-grain rings are only found around stars with masses less than three times the mass of the Sun,” Dr. Rich said.
“This is important because forming planets are thought to create the ringed structure, and our findings suggest that the planet formation process might be different for stars larger than three times the mass of the Sun.”
A paper on the findings will be published in the Astronomical Journal.
Evan A. Rich et al. 2022. Gemini-LIGHTS: Herbig Ae/Be and massive T-Tauri protoplanetary disks imaged with Gemini Planet Imager. AJ, in press; arXiv: 2206.05815
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