Astronomers discover neutron star devouring its brown dwarf companion in "black widow"...

Cal Jeffrey

Posts: 3,522   +1,055
Staff member
In context: Man has forever looked at the stars. These heavenly bodies are fascinating even with the naked eye. However, advancements in observation have made space even more intriguing. Astronomers frequently find astral bodies that push the boundaries of our current knowledge. A recent finding of a binary — possibly trinary — system shows we still have a lot to learn about how the objects in our universe work.

Scientists at Caltech's Zwicky Transient Facility (ZTF) at the Palomar Observatory have discovered a strange pair of binary stars. It is the "black widow" star system designated ZTF J1406+1222. On Wednesday, the astronomers published a paper on their findings in the Nature academic journal. There are a few things that make ZTF J1406+1222 unique.

First, it helps to know what we're dealing with here. Black widows are a rare class of binary star system where a dead neutron star, also known as a pulsar, rotates around a hydrogen-rich star — in this case, a brown dwarf. Over time the pulsar destroys its companion by siphoning material from it and blasting it with the high-intensity gamma radiation (NASA animation below).

One of the things that makes this one strange is that the pulsar is moving very, very fast. While this is typical behavior in black widow systems, this one breaks the record with an orbital period of just over an hour — 62 minutes. The previous record holder was PSR J1653-0158, with a solar year taking only 75 minutes. Other black widow systems are more in the range of eight to nine hours, which is still pretty quick.

"This 62-minute orbit is remarkable because we don't understand how the stars could get into such a tight orbit," says Kevin Burdge, lead author of the study. "The process of the pulsar ablating its companion should actually drive them apart. This is pushing the boundaries of what we thought possible."

Black widows are very rare. They were only first discovered in the 1980s, and since then, astronomers have only found a few dozen others. This one happens to be the closest one we have observed so far, which is another thing that makes it unique.

Finally, rounding out the weirdness, a third star seems to be gravitationally bound to the binary system making it a trinary system. This third star is in a class called "cool subdwarfs." These objects have very little mass or metals, being mainly made up of hydrogen and helium.

What is weird about this third body is that theoretically, it should not be bound to ZTF J1406+1222. It lies about 600 AU from the pair (one AU is the distance between the Earth and our sun), and its low mass means that just about any stellar event should have knocked it out of orbit. Technically, the supernova from when ZTF J1406+1222's pulsar formed should have blasted it out of the system's gravitational grip.

Although ZTF J1406+1222 appears to be a new black widow, the scientists are careful to note their results have not yet been confirmed.

"Our data indicate we are looking at a black widow binary, but it could be something entirely new," Burdge said.

The team is waiting for NASA's Chandra X-ray Observatory to confirm its findings.

Image credit: Syphon and Blast by NASA's Goddard Space Flight Center

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Dd663

It is the "black widow" star system designated ZTF J1406+1222.
Catchy name.

Black widows are very rare. They were only first discovered in the 1980s, and since then, astronomers have only found a few dozen others.
Ah, if only this were true out of context as well...

Although ZTF J1406+1222 appears to be a new black widow, the scientists are careful to note their results have not yet been confirmed. "Our data indicate we are looking at a black widow binary, but it could be something entirely new," Burdge said.
Indeed. So much of our understanding of celestial bodies such as this is based on mathematic extrapolation from data, extrapolation that has the potential to be incorrect.

If they're correct in this case, though, it sounds like they've discovered a pretty cool star system.
 

Plutoisaplanet

Posts: 729   +1,157
One of the things that makes this one strange is that the pulsar is moving very, very fast. While this is typical behavior in black widow systems, this one breaks the record with an orbital period of just over an hour — 62 minutes. The previous record holder was PSR J1653-0158, with a solar day taking only 75 minutes. Other black widow systems are more in the range of eight to nine hours, which is still pretty quick.
You mean the solar year is 62 minutes. A day the time it takes for one rotation to complete while a year is the time it takes for one orbit to complete. Still crazy though, a year being measured in one hour. I wonder how long the days are on that star. On Mercury and Venus, the days are longer than the years, and I wouldn't be surprised if it was the case with this star too.
 
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Dd663

You mean the solar year is 62 minutes. A day the time it takes for one rotation to complete while a year is the time it takes for one orbit to complete. Still crazy though, a year being measured in one hour. I wonder how long the days are on that star. On Mercury and Venus, the days are longer than the years, and I wouldn't be surprised if it was the case with this star too.
How long is the day on the planet Pluto?
 

VitalyT

Posts: 6,271   +6,840
we still have a lot to learn about how the objects in our universe work
Closer to the point - we have a lot to learn about gravity, which is what at the center of everything else. Our modern understanding of gravity is still infantile.

We need Einstein v2 to take us beyond observations and deductions.
 

Plutoisaplanet

Posts: 729   +1,157
A little over 6 Earth days. But with a 248 Earth-year long year, a year on Pluto is over 7000 Pluto days long. Bad news if you have Season Affective Disorder, yer gonna be SAD your whole life.

Also it's chilly, bring a sweater.
Also a flashlight and a freaking oxygen mask. The good news is Charon is so close to Pluto that it probably looks 5x larger than the moon which would be pretty cool to look at.
 
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Dd663

A little over 6 Earth days. But with a 248 Earth-year long year, a year on Pluto is over 7000 Pluto days long. Bad news if you have Season Affective Disorder, yer gonna be SAD your whole life.

Also it's chilly, bring a sweater.
Wouldn't it be over 15,000 Pluto days, assuming exactly 6 Earth days per Pluto day and exactly 248 Earth years per Pluto year?

I may need a bit more than just a sweater.

Also a flashlight and a freaking oxygen mask. The good news is Charon is so close to Pluto that it probably looks 5x larger than the moon which would be pretty cool to look at.
With the sun so far away, how dark is it? As dark as the earth at night? Darker?
 

wiyosaya

Posts: 7,821   +6,787
Also a flashlight and a freaking oxygen mask. The good news is Charon is so close to Pluto that it probably looks 5x larger than the moon which would be pretty cool to look at.
If it can be seen at all. We see the Moon through reflected sunlight. Not much sunlight reaches Pluto, and the amount reflected from Charon is likely exceptionally small.
 

BadThad

Posts: 1,094   +1,283
It will be even more interesting when the Webb eventually looks at it. So much science to be done by Webb - I can't wait!
 
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Dd663

If it can be seen at all. We see the Moon through reflected sunlight. Not much sunlight reaches Pluto, and the amount reflected from Charon is likely exceptionally small.
At the very least, the stars would be quite bright, with no atmosphere nor light pollution to get in the way of viewing them, so the moon could be seen as a massive sphere blocking out the stars.