Level 1 - Absolute Beginner
Scientists found two space objects that are very close. One is a small star. The other is a brown dwarf.
The small star is eating the brown dwarf. It eats very slowly. It takes a tiny bite each year.
They are about 300 light-years from Earth. The brown dwarf goes around the star in less than two hours.
A team from MIT wrote about it in a science journal. They say it may go on for a very long time.
- star
- a big ball of hot gas in space that makes light
- brown dwarf
- an object bigger than a planet but too small to be a star
- slowly
- not fast
- light-year
- the long way that light travels in one year
- scientist
- a person who studies nature and the world
- journal
- a magazine where scientists share their work
- orbit
- to go around another object in space
- bite
- a small piece that you take with your mouth
Level 2 - Elementary
Astronomers have found a rare pair of objects about 300 light-years from Earth. A small red star is slowly pulling gas from a brown dwarf that travels around it. The system is called ZTF J0440+2325.
A brown dwarf is bigger than a planet but too small to burn like a star. This one circles its partner about every 87 minutes. Gas flows from the brown dwarf and hits the surface of the star, where it makes a hot spot.
The flow is very small. The brown dwarf loses about one hundred-thousandth of the mass of Earth each year. Because of this, the meal could continue for hundreds of thousands of years, or even billions.
A team led by MIT reported the discovery in the journal Nature Astronomy. Kevin Burdge, an MIT physics professor, said stars usually swallow their partners quickly. Here the process is gentle.
- astronomer
- a scientist who studies stars and planets
- red dwarf
- a small, cool star
- brown dwarf
- an object too small to be a true star
- circle
- to move around something
- hot spot
- a small area that is much hotter than the area around it
- mass
- the amount of material that something has
- discovery
- something new that people find
- gentle
- soft and slow, not strong
Level 3 - Intermediate
A team led by MIT has described a pair of objects that astronomers call a gentle form of stellar cannibalism. About 300 light-years away, in a system named ZTF J0440+2325, a red dwarf star is steadily drawing material from a brown dwarf that orbits it every 86.65 minutes.
Brown dwarfs sit between planets and stars: they are too light to fuse hydrogen the way a star does, yet far heavier than a planet. In this pair, a stream of gas leaves the brown dwarf and strikes the red dwarf, heating a large hot spot at the point of impact. That glow is part of how the researchers detected the transfer.
The scale of the meal is tiny. The researchers estimate that the brown dwarf loses roughly one hundred-thousandth of an Earth mass per year, so the process could run for hundreds of thousands of years and perhaps for billions. The report in Nature Astronomy describes it as the first observed case of a low-mass object steadily feeding from another low-mass object.
Kevin Burdge, an MIT physics professor, contrasted the system with the usual picture, in which a star swallows a companion outright, as the Sun will one day engulf nearby worlds. Here, he said, the transfer is gradual, which may help scientists test ideas about how close pairs of small stars evolve.
- stellar
- relating to stars
- cannibalism
- feeding on a member of one's own kind
- fuse
- to join together, as atoms do inside a star
- stream
- a steady flow of something
- impact
- the moment when one thing hits another
- estimate
- to calculate roughly, without being exact
- engulf
- to surround and swallow completely
- evolve
- to change slowly over a long time
Level 4 - Advanced
Stellar cannibalism usually conjures violence: a bloated star engulfing a companion, or a black hole tearing apart its neighbor. A study led by MIT and published in Nature Astronomy documents the opposite, a protracted and almost courteous meal, in a system catalogued as ZTF J0440+2325, roughly 300 light-years from Earth.
There, a red dwarf is accreting material from a brown dwarf, a substellar object too light to sustain hydrogen fusion yet far more massive than any planet. The two bodies are locked in an orbit lasting only 86.65 minutes. Gas streams from the brown dwarf, strikes the red dwarf's surface and heats a conspicuous hot spot, the signature that revealed the exchange.
The accounting is humbling. The brown dwarf is shedding about a hundred-thousandth of an Earth mass annually, a rate at which the interaction could persist for hundreds of thousands of years, conceivably for billions. According to the paper, it is the first observed instance of one low-mass object steadily siphoning matter from another.
Kevin Burdge, an MIT physics professor, framed the finding against the conventional script, in which a star ends a companion's existence in a single catastrophic episode. A leisurely transfer offers astronomers a rare laboratory for studying how close, low-mass pairs exchange material, lose angular momentum and evolve, though conclusions will rest on further observation of this and similar systems.
- protracted
- lasting longer than expected
- accreting
- gathering matter, especially under gravity
- substellar
- too small to be a true star
- conspicuous
- easy to see or notice
- siphon
- to draw off a liquid or gas gradually
- catastrophic
- causing sudden and great damage
- angular momentum
- a measure of how much spin or orbital motion an object has
- humbling
- making one feel small or less proud