NASA’s Spitzer Space Telescope spots star-sized cloud of debris from distant collision, Science News
NASA’s Spitzer Space Telescope has spotted a star-sized cloud of debris from a distant collision.
The research, published in The Astrophysical Journal, discusses in detail the major collisions between rocky bodies that have shaped our solar system.
In the study, a group of astronomers led by Kate Su, a research professor at the University of Arizona’s Steward Observatory, report the first sightings of a cloud of debris from one such collision as he passed in front of his star and briefly blocked the starlight. . They call it a transit.
Coupled with knowledge of the star’s size and luminosity, this allowed researchers to directly determine the size of the cloud shortly after impact, estimate the size of objects that collided, and monitor the speed at which the cloud dispersed.
Read also | New solar physics? Mysterious vortex waves discovered on the Sun are traveling faster than expected
Beginning in 2015, Su’s team began making routine observations of a 10-million-year-old star called HD 166191. At this time in a star’s life, dust left over from its formation clumped together to form rocky bodies called planetesimals.
Asteroids are remnants of planetesimals from the formation of our own solar system, and around other stars they are the seeds of future planets. Once the gas that previously filled the space between these objects disperses, catastrophic collisions between them become common.
Anticipating that they might see evidence of one of these collisions around HD 166191, the team made over 100 observations of the system with Spitzer. While the objects would be too small and too distant to be resolved with a telescope, their collisions produce large amounts of dust.
Spitzer detected infrared light, wavelengths slightly longer than human eyes can see; it is an ideal range for detecting dust, including debris created by protoplanet collisions.
Read also | NASA is collecting names to send into space aboard the Orion capsule to the Moon
“For the first time, we have captured both the infrared glow from the dust and the blur that the dust introduces as the cloud passes in front of the star,” said astronomer Everett Schlawin of the Steward Observatory at the University of arizona.
The multi-wavelength transit data confirms that the transits were caused by a dust cloud passing in front of the star and moving at a rapid rate – as it grew wider and more opaque during the first two transits but showed very little evidence of the cloud thereafter.
This data allowed the team to determine the location, shape and size of the debris cloud. The team’s work suggests that the cloud was very elongated, with a minimum surface area estimated to be three times that of the star.
However, the amount of infrared brightening that Spitzer saw suggests that only a small portion of the cloud passed in front of the star and that the total amount of debris created by this violent event covered an area hundreds of times greater than that of the star.
Read also | NASA is opening a 50-year-old vacuum-sealed lunar gas and soil tube
“There is no substitute for being an eyewitness to an event,” said study co-author George Rieke, Regents Professor of Astronomy at the University of Arizona.
“All of the cases reported to date by Spitzer have not been resolved, with only theoretical assumptions about what the actual event and debris cloud might have looked like.”
“By looking at the dusty debris disks around young stars, we can essentially look back in time and see the processes that may have shaped our own solar system,” Su said.
“By learning the outcome of collisions in these systems, we can also get a better idea of how often rocky planets form around other stars.”
The team continues to keep tabs on the star along with other NASA infrared facilities, including the Stratospheric Observatory for Infrared Astronomy and the Infrared Telescope Facility. These observations not only make it possible to keep a record of the overall evolution of the infrared flux, but also provide additional information on the composition of the fine dust freshly generated by spectroscopy.
In particular, future observations with the mid-infrared instrument aboard NASA’s James Webb Space Telescope will provide additional insight into the physical state of these large collisions by studying the mineralogy of the dust.
(With agency contributions)