Space News & Blog Articles

Tracking exoplanets is hard – especially when that exoplanet is so far away from its parent star that the normally used “transit” method of watching it dim the light of the star itself is ineffectual.  But it really helps if the planet is huge, and has its own infrared glow, no matter how far away from its star it might be.  At least those properties allowed a team of scientists from the University of Hawai’i to track a particular exoplanet called (and we’re not kidding) Coconuts-2b.

We here at UT are no stranger to whimsical astronomical naming, but the Cool Companions on Ultrawide Orbits (Coconuts) survey may take the cake.  This new planet that survey turned up is almost 6 times the size of Jupiter and is orbiting its star at an astonishing 6,000 times the distance from the Earth to the Sun.

Star field from the WISE survey showing the two planets of the Coconuts 2 system around its host star.
Credit – NASA / WISE / Zhang et al.

That incredible distance made the original discoverers of the planet back in 2011 using WISE think it was “rogue”, meaning it wasn’t gravitationally bound to any particular star.  They were only able to see it because the planet itself is still glowing with a waste heat built up during the planet’s formation, which is visible in the infrared spectrum.

But new research shows that Coconuts-2b is in fact gravitationally bound to a star, L 34-26, just as an absurdly far distance. The system it is bound to isn’t even all that far from Earth – at 35 light years away it is one of the closer exoplanets found of the 4,000 so far. It’s also not even the planet that is the farthest from its host star – that honor goes to the planet 2MASS J21265040-8140293, which is separated at an astonishing 7400 AU from it’s parent star, TYC 9486-927-1. Those names so how much more appealing a name like “Coconuts 2b” truly is.

Different spectra of the Coconut 2 system.
Credit – NASA / UNWISE & Melina Thevenot

Names aside, the experience on either of those worlds would be so very different from the experience as we know it here on Earth. In addition to the crushing gravity, night time and day time on the planet would appear to be almost the same.  The star it is orbiting would simply appear as a bright red star in a sky that is similarly full of them.

How do you track an asteroid that hit the Earth over 60 million years ago?  By using a combination of geology and computer simulations, at least according to a team of scientists from the Southwest Research Institute (SwRI).  Those methods might have let them solve a long-standing mystery of both archeology and astronomy – where did the asteroid that killed the dinosaurs come from?

The fact that an asteroid impact was the catastrophe that finally killed the dinosaurs is now widely accepted in scientific circles.  Now known as the “Chicxulub event”, it was named after the 145 km wide crater in the Yucatan peninsula that the 10 km wide asteroid caused when it impacted the planet about 66 million years ago.

When an asteroid struck the Yucatan region about 66 million years ago, it triggered the extinction of the dinosaurs. This artist’s depiction is a large exaggeration of the actual size of the 10 km wide object, but shows the force such an impact could have.
Credit: NASA/Don Davis

Large creatures like dinosaurs having evolved at all, and their reigning over the Earth for hundreds of millions of years, shows that such large impacts were not very common in their time – so where did the impactor come from?  Turns out it was probably from the outer asteroid belt.

Two main findings led to this conclusion – the first was some geology samples collected from rocks formed around the time of the impact.  The second was a detailed model of different types of asteroids and comets and how they might interact with the different forces at play in the asteroid belt.

UT video on asteroid defense Part 1

Sixty six million year old geology samples are not easy to come by, but the SwRI team managed to, and noticed some similarities in the makeup of the rock they contained.  It pointed to the Chicxulub impactor being a “carbonaceous chondrite” asteroid, which is a common type of asteroid, many of which pass near the Earth.  The only difference is that none of them are anywhere near close to the scale of the 10 km wide Chicxulub asteroid.