Telescope “sunglasses” find brightest pulsar outside our galaxy

The spinning star is more than 10 times brighter than any seen outside the Milky Way.

Australian astronomers discovered the brightest pulsar ever seen outside the Milky Way — by putting “sunglasses” on a telescope.

The spinning stars: At the end of their lives, some massive stars collapse into super-dense neutron stars, and some of those neutron stars spin incredibly fast while emitting two beams of light in opposite directions, like a lighthouse — those are pulsars.

If a pulsar’s beams of light cross our line of sight, the star appears to flicker. Astronomers can look for evidence of that flickering in telescope data, but if the pulsar is unusual — e.g., it’s spinning faster than normal or has a particularly wide light beam — it can go undetected.

“I didn’t expect to find a new pulsar, let alone the brightest.”

Yuanming Wang

Polarizing idea: A team led by University of Sydney astronomer Tara Murphy took a different approach to pulsar hunting, focusing instead on the ability of some pulsars to “polarize” light.

Light travels in waves, and in its natural state, it’s “unpolarized,” meaning the waves move randomly in three dimensions (up and down, left and right). 

However, light can become “polarized” — its waves then move in just two dimensions along a single plane. Something as simple as reflecting off water can polarize light, and the strong magnetic field of a pulsar can polarize it, too. 

“Extreme pulsars are one of the missing pieces in the vast picture of the pulsar population.”

Yuanming Wang, David Kaplan, and Tara Murphy

Stellar sunglasses: Polarized sunglasses help us see by blocking any light that isn’t vertically polarized (including the horizontally polarized light we perceive as glare), and Australia’s ASKAP radio telescope has its own “sunglasses” that allow it to capture only polarized light. 

Using that feature, Murphy’s team was able to spot a pulsar that had previously escaped detection due to its wide light beam. They then confirmed the pulsar using the MeerKAT radio telescope in South Africa.

pulsar
The newly discovered pulsar as seen from the MeerKAT telescope with and without “sunglasses.” Credit: Yuanming Wang

This pulsar — PSR J0523-7125 — is located within the Large Magellanic Cloud (LMC). That’s the only galaxy other than the Milky Way in which we’ve spotted pulsars, and this one is more than 10 times brighter than any other seen in the LMC.

“This was an amazing surprise,” said lead author Yuanming Wang. “I didn’t expect to find a new pulsar, let alone the brightest. But with the new telescopes we now have access to, like ASKAP and its sunglasses, it really is possible.”

The big picture: To truly understand pulsars, we need to study all kinds of them, including the “weird” ones that escape our traditional detection techniques — and this study demonstrates how we can find them.

“Extreme pulsars are one of the missing pieces in the vast picture of the pulsar population … This discovery is just the beginning,” the discoverers of the new pulsar wrote in the Conversation

We’d love to hear from you! If you have a comment about this article or if you have a tip for a future Freethink story, please email us at [email protected].

Related
Astronomers detect “mystery molecule” in exoplanet’s atmosphere
Thanks to the James Webb Space Telescope, we now know more about the atmosphere of WASP-39b, a distant gas giant, than any other exoplanet.
What is the largest planet out of all the ones we know?
The “upper limit” to the size of our planets is exceeded in other stellar systems, but double Jupiter’s radius seems to be the limit.
NASA “Flashlight” will hunt for hidden water on the moon
NASA’s Lunar Flashlight mission will use reflections from laser light to measure lunar water hidden in permanently shadowed craters.
Meteorite blasts “biggest new crater” NASA has ever seen into Mars 
A meteorite impact that caused a marsquake and created a massive new Mars crater could shape our plans to send people to the Red Planet.
Einstein’s theory of general relativity passes another test, with implications for dark matter and dark energy 
Scientists carried out an ultra-precise test of a core premise of Einstein’s modern theory of gravity. The theory stood up.
Up Next
Perseverance rover
Subscribe to Freethink for more great stories