Thanks to NASA’s Spitzer and Swift space telescopes joining forces to study a microlensing event, astronomers had a rare achievement of locating an elusive brown dwarf planet.
The debut collaboration made the microlensing event a useful occasion. During the phenomenon, a distant star looks brighter thanks to the gravitational pull of a cosmic object in the foreground, which, in turn, makes highlighting of low-mass bodies that orbit big stars an easy job.
“We want to understand how brown dwarfs form around stars, and why there is a gap in where they are found relative to their host stars,” Yossi Shvartzvald, a NASA postdoctoral fellow and the lead author of the study, said in a news release.
The discovery and analysis of the brown dwarf and the microlensing data have been published in The Astrophysical Journal.
What’s Microlensing?
Microlensing magnifies objects that are invisible to the eyes of astronomers. Dwarfs are not full stars but are entities with a size midway between a star and a planet. They are handicapped with the problem of inadequate energy-forming capacity for triggering nuclear fusion like stars.
Though brown dwarfs orbit a larger star, locating them within three astronomical units to the sun was not easy. That is what makes the microlensing event unique, and that led to the perfect spotting of the brown dwarf by the astronomers.
An astronomical unit or AU defines the distance between Earth and the sun.
According to experts, the microlensing event helped researchers to take accurate information about the newly discovered brown dwarf in terms of size and the distance from the host star by watching it from various angles.
“In the future, we hope to have more observations of microlensing events from multiple viewing perspectives, allowing us to probe further the characteristics of brown dwarfs and planetary systems,” said JPL scientist Geoffrey Bryden.
Multiple Vantage Points
Combining data from space-based and ground-based telescopes, the researchers grandly assessed the newly discovered brown dwarf that carried a name OGLE-2015-BLG-1319 and had a mass between 30 and 65 Jupiter masses.
By deploying multiple telescopes to watch the event, the scientists drew the advantage of creating a “parallax,” which is actually the difference in positions seen from two different points in space.
“Anytime you have multiple observing locations, such as Earth and one, or in this case, two space telescopes, it’s like having multiple eyes to see how far away something is,” Shvartzvald added.
The microlensing data was then used for calculating the relationship between the dwarf’s mass and distance.
In terms of position, Spitzer was over 1 AU beyond the Earth, and Swift stayed in a lower Earth orbit.
Shvartzvald said simulations had suggested that Swift would be capable of measuring the parallax for less massive objects, which may not orbit stars.
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