A group of astronomers has found a binary system of two extremely cool dwarf stars that are so close to one another that they appear to be a single star.
They are noteworthy because their year is smaller than one Earth day and it only takes them 20.5 hours to orbit each other. Additionally, they are much older than comparable systems.
Although they are the most common stars in the cosmos, ultra-cool dwarf stars are invisible to the human eye. We require infrared telescopes to see them since they only produce infrared light due to their extremely low mass.
They are intriguing objects because, according to theory, stars this close together should exist, but this system marks the first time that such a tight proximity has been seen by astronomers.
At the 241st Meeting of the American Astronomical Society in Seattle, a group of astronomers presented their research. The study's principal investigator was Northwestern University astrophysicist Chih-Chun "Dino" Hsu. The device is known as LP 413-53AB.
The study's principal investigator, Chih-Chun "Dino" Hsu of Northwestern University, remarked, "It's fascinating to discover such an extreme system. Although we were aware that these systems should exist in theory, they had not yet been discovered.
In calibrating our theoretical models for low-mass binaries, the extremes of nature are crucial. There were just three short-period, ultra-cool binaries that were known to astronomers before this discovery.
The pair was located in archived data by the research team. Using an algorithm Hsu created that models stars based on their spectral properties, they were going over data.
However, the stars in those older pictures were simply lined up and appeared as one star. For a binary pair this tight, the odds of such occurring are substantial.
However, Hsu and his colleagues believed the data was strange, so they used the Keck Observatory to investigate the star more carefully. The light curve altered so swiftly, according to the observations, that there must be two stars.
They eventually understood that they had discovered the nearest binary pair ever discovered.
Professor Adam Burgasser of UC San Diego remarked, "When we were conducting this measurement, we could see things shifting during a couple of minutes of observation." When Hsu was a PhD candidate, Burgasser served as his advisor.
"Most of the binary stars we monitor have yearly orbital periods. Consequently, you are measured every few months. After some time has passed, you can put the puzzle together. We were able to watch the spectral lines separate in real time using this method. Observing events in the universe take place in our time is astounding."
Hsu compared the stars to our Solar System and another well-known system to illustrate how near the stars are to one another.
Compared to Jupiter and Callisto, one of Jupiter's Galilean moons, the pair are closer together. Additionally, it is closer than TRAPPIST-1b, the red dwarf star closest to TRAPPIST-1.
Compared to the other three such systems that astronomers are aware of, the stars are substantially older. LP 413-53AB is much older than the other three, which are only up to 40 million years old. Both it and our Sun are several billions of years old.
The fact that they are so old suggests that the stars were not always so close to one another. They may have initially entered an even closer orbit, according to the researchers.
These stars would have been stacked on top of one another when they were young, roughly one million years ago, according to Burgasser.
It's also possible that the stars were initially a pair with larger orbits before gradually getting closer.
Another scenario is that the stars were formerly a triple-star system. One star may have been expelled at the same time that the other two stars were brought into closer orbits by gravitational interactions.
Perhaps more observations of the unusual system could provide an answer.
These kinds of stars are intriguing to astronomers because of what they might reveal about habitable planets. Because ultracool dwarfs are so cool and dim, only a small area can support life.
The planets could only be warmed in that way if they were to support liquid surface water. However, in the case of LP 413-53AB, the habitable zone distance coincides with the star orbit, ruling out the existence of habitable extrasolar planets.
These extremely cool dwarfs are our sun's neighbours, according to Hsu. "It is helpful to start with our close neighbours in order to find possibly livable hosts. However, there might not be many livable worlds to be found if tight binaries are typical among ultracool dwarfs."
Astronomers are interested in learning if there are additional tight systems now that they have discovered one. The only way to comprehend each of these circumstances is in that way.
With only one piece of data, drawing any inferences is challenging.
However, astronomers are unsure if the reason they've only found one is because they're so uncommon or because they're so challenging to find.
These systems are uncommon, according to Chris Theissen, Chancellor's Postdoctoral Fellow at UC San Diego and research co-author.Astronomers are interested in learning if there are additional tight systems now that they have discovered one. The only way to comprehend each of these circumstances is in that way.
With only one piece of data, drawing any inferences is challenging.
However, astronomers are unsure if the reason they've only found one is because they're so uncommon or because they're so challenging to find.
These systems are uncommon, according to Chris Theissen, Chancellor's Postdoctoral Fellow at UC San Diego and research co-author.
"However, we are unsure if their rarity stems from their rarity of occurrence or from our inability to locate them. That is a broad question. Now that we have a single data point, we may begin to expand. This information had been stored in the archives for a while. We can look for more binaries like this using Dino's programme."
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