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The Oldest Known Asteroid Family has finally been identified by Astronomers

Identifying the very oldest asteroid families, those billions of years old, is challenging, because over time, a family spreads out

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Oldest known asteroid family
An asteroid family. Wikimedia

August 08, 2017: Astronomers have identified the oldest known asteroid family, which extends throughout the inner region of the main asteroid belt.

The team also discovered a relatively sparse region of the main asteroid belt, where the few asteroids present are likely pristine relics from early in solar system history.

“The family we identified has no name, because it is not clear which asteroid is the parent,” said Kevin Walsh, astronomer at Southwest Research Institute in the US and co-author of a study published online in the journal Science.

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“This family is so old that it appears to have formed over four billion years ago, before the gas giants in the outer solar system moved into their current orbits. The giant planet migration shook up the asteroid belt, removing many bodies, possibly including the parent of this family,” Walsh said.

Finding and studying asteroid families allows scientists to better understand the history of main belt asteroids.

But identifying the very oldest asteroid families, those billions of years old, is challenging, because over time, a family spreads out.

As asteroids rotate in orbit around the Sun, their surfaces heat up during the day and cool down at night.

This creates radiation that can act as a sort of mini-thruster, causing asteroids to drift widely over time.

After billions of years, family members would be almost impossible to identify, until now.

The team used a novel technique, searching asteroid data from the inner region of the belt for old, dispersed families.

They looked for the “edges” of families, those fragments that have drifted the furthest.

“Each family member drifts away from the centre of the family in a way that depends on its size, with small guys drifting faster and further than the larger guys,” said team leader Marco Delbo, an astronomer from the Observatory of Cote d’Azur in Nice, France.

“If you look for correlations of size and distance, you can see the shapes of old families,” Delbo noted.

“By identifying all the families in the main belt, we can figure out which asteroids have been formed by collisions and which might be some of the original members of the asteroid belt,” Walsh said.

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“We identified all known families and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids. These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked like just after it formed,” Walsh noted.

The team plans to apply this new technique to the entire asteroid belt to reveal more about the history of the solar system by identifying the primordial asteroids versus fragments of collisions. (IANS)

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Astronomers Discover the ‘Biggest Stellar Puzzle’, Bizarre Star that Refuses to Die

The study calculated that the star that exploded was at least 50 times more massive than the Sun and probably much larger.

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This star shines brighter every time it explodes. Read to know more! (representative image) Wikimedia

New York, November 9, 2017 : An international team of astronomers has made a bizarre discovery – a star that refuses to stop shining despite exploding more than once over a period of 50 years.

The explosions of stars, known as supernovae, have been observed in the thousands and in all cases they marked the death of a star.

But a new study, published in the journal Nature, challenges known theories about the death of stars. Their observations included data from Keck Observatory on Maunakea in Hawaii.

“The spectra we obtained at Keck Observatory showed that this supernova looked like nothing we had ever seen before. This, after discovering nearly 5,000 supernovae in the last two decades,” said study co-author Peter Nugent from Lawrence Berkeley National Laboratory in the US.

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“While the spectra bear a resemblance to normal hydrogen-rich core-collapse supernova explosions, they grew brighter and dimmer at least five times more slowly, stretching an event which normally lasts 100 days to over two years,” Nugent said.

The supernova, named iPTF14hls, was discovered in September 2014 by the Palomar Transient Factory. At the time, it looked like an ordinary supernova.

Several months later, astronomers at Las Cumbres Observatory in the US noticed the supernova was growing brighter again after it had faded.

When astronomers went back and looked at archival data, they were astonished to find evidence of an explosion in 1954 at the same location.

This star somehow survived that explosion and exploded again in 2014.

“This supernova breaks everything we thought we knew about how they work. It’s the biggest puzzle I’ve encountered in almost a decade of studying stellar explosions,” said lead author Iair Arcavi, a NASA Einstein postdoctoral fellow at LCO and the University of California Santa Barbara.

The study calculated that the star that exploded was at least 50 times more massive than the Sun and probably much larger.

Supernova iPTF14hls may have been the most massive stellar explosion ever seen. The size of this explosion could be the reason that conventional understanding of the death of stars failed to explain this event.

Astronomers continue to monitor the supernova, which remains bright three years after it was discovered. (IANS)

 

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Astronomers discovered Sun-like star that devoured its own planets

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Astronomers discovered Sun-like star that devoured its own planets

New York, Oct 13: Astronomers have discovered that a Sun-like star lurking around 350 light-years away consumed the rocky equivalent of 15 Earths.

Dubbed Kronos after the child-eating Titan of Greek mythology, the star is the clearest and most dramatic case yet of a Sun-like star consuming its own planets, said Semyeong Oh, astrophysicist at Princeton University in New Jersey and lead author of the study.

“Even if our Sun ate the entire inner solar system, it wouldn’t come close to the anomaly we see in this star,” study co-author David Hogg from the Flatiron Institute in New York added.

The research did not begin as a hunt for a planet-eater.

Oh was analysing a catalog of new star data collected by the European Space Agency’s Gaia spacecraft for pairs of stars with similar speeds and trajectories.

Such duos are typically twin stars that formed close together from the same ingredients.

The analysis ultimately led to the identification of Kronos and its lesser known brother Krios.

Their official designations are HD 240430 and HD 240429, and they are both about 350 light years from Earth.

The keys to the discovery were first confirming that the widely separated pair are in fact a binary pair, and secondly observing Kronos’ strikingly unusual chemical abundance pattern, Oh explained in a statement released by the Princeton University.

Other co-moving star pairs have had different chemistries, Oh explained, but none as dramatic as Kronos and Krios.

Most stars that are as metal-rich as Kronos “have all the other elements enhanced at a similar level,” she said, “whereas Kronos has volatile elements suppressed, which makes it really weird in the general context of stellar abundance patterns.”

In other words, Kronos had an unusually high level of rock-forming minerals, including magnesium, aluminium, silicon, iron, chromium and yttrium, without an equally high level of volatile compounds — those that are most often found in gas form, like oxygen, carbon, nitrogen and potassium, the study said. (IANS)

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Researchers Claim The Existence Of Planet Nine

Researchers from an American University have laid evidences to prove the presence of Planet Nine

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Planet Nine
Kuiper Belt indicates the presence of Planet Nine
  • The science communities since a long time have been debating upon the existence of Planet Nine. 
  • Space highlights different shreds of evidence based on which scientists are stating the claim.

What Is Planet Nine?

Planet Nine is a hypothetical planet present in the far outer Solar System, whose mass is estimated to be 10 times more than the mass of Earth. The planet is said to be 20 times farther than the sun than Neptune is.

What Do Researchers Have To Say?

Dr Konstantin Batygin, a planetary astrophysicist at the California Institute of Technology, said that there were five different lines of observational evidence which pointed to the existence of Planet Nine. He stated that if this theory does not sound believable, then people would have to come up with the answers of the five pieces of evidence which could lead to further confusion.

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Batygin in 2016 published a study examining the six known objects in the Kuiper Belt, a  circumstellar disc in the Solar System beyond the planets that extends from the orbit of Neptune towards interstellar space.

The study examines all the objects have elliptical orbits pointing in the same direction and are tilted the same way. These serve as evidence to the planet’s existence.

It is being said that the objects are tilted 30 degrees downward compared to the plane where the eight official planets circle the sun. Researchers also made use of computer simulations of the solar system including the Planet Nine and to demonstrate that there should be more objects tilted a whopping 90 degrees to solar plane. It was revealed that five such objects, which fit these parameters were already known.

The study led to the birth of two more ideas. Researchers said that this planet could have tilted the planets of the solar system during the last 4.5 billion years.

Planet Nine’s existence could also tell the reason as to why Kuiper Belt objects orbit in the opposite direction as compared to other things in the solar system.

-Prepared by Megha Acharya of NewsGram.

(the story was originally published in PTI)