Seeing through the fog: Pinpointing young stars and their protoplanetary disks

Imagine walking through a dense fog in the middle of the night and seeing light from cars and towns in the distance. It is almost impossible to tell if the lights are in the fog or beyond it. Astronomers trying to find young stars face a similar problem, because the light from stars they are hunting is shining through big regions of hazy gas and dust in space.

The hearts of these clouds are often breeding grounds for young stars and planets, the perfect places to try to figure out how heavenly bodies form.

A group of scientists in the astronomy department at BU have found a way to cut through the fog. They have developed a new way to measure the haziness of the dust cloud, which will allow them to detect the presence of planet-forming structures around young stars. They used their technique to get a better look at the insides of the dust cloud located 450 light-years from Earth. There is a two-star system that is still in its infancy and is likely to create multiple new planets.

"We are trying to look through the fog of the cloud to see what these stars are doing, they are like flashlight shining through the cloud." The Astrophysical Journal published the findings.

Studying systems like this can help scientists understand how stars and planets form. A brown dwarf is sometimes called a failed star because it doesn't have the same chemistry as a brighter star. The young star and brown dwarf have disks around them.

Anneliese Rilinger, a fifth-year graduate student in BU's astronomy department, began studying the star system using radio waves collected by the ALMA, the largest radio telescope in the world. Rilinger and Catherine Espaillat, an associate professor of astronomy and coauthor on the new paper, had previously published a study looking at the disks surrounding the stars and doing detailed modeling of the structures of the disks.

The interest in her work by the rest of the team, including Rilinger, Espaillat, and BU senior research scientist Thushara Pillai, led to them testing her observations of the same system using near-IR light. They wanted to show that it was possible to model the disk locations using alternate methods.

Light waves go in multiple directions when the stars emit light. The light waves are affected by the properties of the dust grains and the magnetic field in the cloud. The researchers used a near-infrared polarimeter at BU to measure the polarization of light passing through the cloud. The research team was able to see the signatures of the stars, which could tell them the orientation of the disks. The challenge was how to subtract the effects of the surrounding cloud to figure out the nature of the light coming from the stars.

The team confirmed that the near-infrared data matched the radio wave data, showing that it is possible to measure disks without large-scale tools. The disks are parallel to each other and situated to the magnetic field of the larger cloud, which was discovered by their work. This system is rare and gives researchers the chance to learn more about how disks form planets.

The knowledge of how to remove cloud contributions from the stars and young stellar objects is something that has not been done before.

Though they are still in the process of forming planets, the brown dwarf and young star in the Taurus cloud already have lower-mass companions that straddle the boundary between being a planet or another brown dwarf. Over the next five million years, planets are likely to form in their slice of space.

More information: Dan P. Clemens et al, Near-infrared Polarization from Unresolved Disks around Brown Dwarfs and Young Stellar Objects, The Astrophysical Journal (2022). DOI: 10.3847/1538-4357/ac415c Journal information: Astrophysical Journal Citation: Seeing through the fog: Pinpointing young stars and their protoplanetary disks (2022, May 16) retrieved 17 May 2022 from https://phys.org/news/2022-05-fog-young-stars-protoplanetary-disks.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.