‘Failed’ Star Rapidly Orbits ‘Dead’ Star in Weird Stellar Pairing

white-dwarf
ESO

The galaxy may be filled with weird stellar wonders, but you’d be hard-pressed to find a binary system stranger than WD1202-024.

First thought to be an isolated white dwarf star approximately 40% the mass of our sun, astronomers studying observational data from NASA’s Kepler space telescope realized the stellar husk has company. In an extremely fast 71-minute orbit, the star has a brown dwarf, 67 times the mass of Jupiter, in tow — an unprecedented find.

White dwarfs are formed after sun-like stars run out of fuel and die. This will be the fate of our sun in about five billion years time, after it becomes depleted of hydrogen in its core and puffs-up into a red giant. Shedding its outer layers after a period of violent stellar turmoil, a planetary nebula will form with a tiny mass of degenerate matter — a white dwarf — in its center. Earth would be toast long before the sun turns into a red giant, however.

But in the case of WD1202-024, it seems that when it was a young star (before it passed through its final red giant phase), it had a brown dwarf in orbit.

Commonly known as “failed stars,” brown dwarfs are not massive enough to sustain sufficient fusion in their cores to spark the formation of a star. But they’re too massive to be called planets as they possess the internal circulation of material that is more familiar to stars (so with that in mind, I like to refer to brown dwarfs as “overachieving planets”). They are the bridge between stars and planets and fascinating objects in their own right.

But the brown dwarf in the WD1202 binary couldn’t have formed with only a 71-minute orbit around the white dwarf; it would have evolved further away. So what happened? After carrying out computer simulations of the system, the international team of researchers found a possible answer.

“It is similar to an egg-beater effect,” said astronomer Lorne Nelson, of Bishop’s University, Canada, during the American Astronomical Society meeting in Austin, Texas on June 6th. “The brown dwarf spirals in towards the center of the red giant and causes most of the mass of the red giant to be lifted off of the core and to be expelled. The result is a brown dwarf in an extraordinarily tight, short-period orbit with the hot helium core of the giant. That core then cools and becomes the white dwarf that we observe today.”

In the future, the researchers hypothesize, the brown dwarf will continue to orbit the white dwarf until energy is depleted from the system via gravitational waves. In less than 250 million years, the orbital distance will be so small that the extreme tidal forces exerted by the white dwarf will start to drag brown dwarf material into the star, cannibalizing it.

This will turn WD1202 into a cataclysmic variable (CV), causing its brightness to flicker as the brown dwarf material is extruded into an accretion disk orbiting the white dwarf.

What a way to go.

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What REALLY Happened to the LCROSS Centaur?

<conspiracy mode>

In the early hours of Friday morning at 4:31am, the spent Centaur rocket from the NASA LCROSS mission slammed into the surface of the south pole of the moon. What was the point in that?

Well, NASA was hoping that the tumbling chunk of metal the size of a small bus would kick up a huge plume of dust. Following 4 minutes behind was the shepherding LCROSS spacecraft, also on a kamikaze dive, hoping to drop through the plume, sensitive instruments ready to analyse the dust for water.

I know what you’re thinking: what right does NASA have to BOMB the Moon? They have NO RIGHT AT ALL!!

It turns out that they are actually waging a top secret war against the population of peaceful extraterrestrials that live on the far side of the Moon. This “experiment” was in fact a reckless attack against a superior alien civilization, intended to strike fear into the hearts of the aliens.

If you were to believe the NASA promo video of the event, this should have been spectacular, vast quantities of lunar regolith blasting into space… it should have been akin to the biggest Fourth of July firework detonating. This “shock and awe” tactic is typical of the US space agency. The huge mass of the Centaur (a little under 2400kg), combined with its break-neck speed (1.5 miles per second) should have unleashed the equivalent energy of a tonne of TNT exploding. However, what NASA didn’t tell us was that Centaur was also carrying plutonium, so the explosion should have been a LOT bigger, easily visible to the naked eye.

But what did we see? Nothing. What did NASA see? Nothing. So what happened? Well, the answer to that is a little more compelling than what NASA is telling us.

Yes, they can show us images of a meagre “flash” as the Centaur hit inside a lunar crater, but I don’t think Centaur hit the Moon at all… the Centaur rocket was swallowed by the Moon.

Don’t believe me? Moments before impact, NASA’s lunar satellite — the Lunar Reconnaissance Orbiter (LRO) — was approaching the location and it took this photo. What you see here will shock you. It will astound you. And what’s more, it’s REAL.

Aliens DO live on the Moon, and they were prepared for the NASA bombing…

lcross-conspiracy

</conspiracy mode>

I’m sorry, I couldn’t resist. In the run-up to the LCROSS impact, the sheer amount of crazy conspiracy theories hit fever-pitch (I blogged about it on Space Disco 2 hours before impact). Some of my favourite theories involved alien civilizations on the lunar surface, plutonium on LCROSS (to destroy the Moon), the “fact” that it was all just a publicity stunt and the LCROSS mission didn’t exist at all… and the strange theory that the Moon feels pain.

Yawn.

A polite message to the conspiracy theorists: Come on people, stop making stuff up and understand the real science. You might find reality more interesting than your twisted fantasies.

Image: The Sarlacc pit monster from Star Wars, Copernicus lunar crater and the LCROSS Centaur rocket. Photoshopping: Me.

Oops… I really geeked out this time, didn’t I.