Around 10000 years ago, a very bright star exploded in the constellation Vela. This explosion created a glowing spinning object called a pulsar that works like a cosmic lighthouse. The pulsar also acts as an engine that launches material at almost the speed of light, which forms a chaotic mix of particles and magnetic fields colliding into the gas around it. This is what we call a pulsar wind nebula.
The image shows the Vela pulsar, which is a star that sends out X-rays at its center. The light blue halo in the picture represents the first of these X-ray polarizations detected by NASA’s IXPE. There’s also a faint blue line that points to the top right corner – this is actually a jet of high energy particles shooting out at almost half the speed of light. Lastly, the pink arcs on either side represent regions where the pulsar wind causes high-energy particles to accelerate and spin around.
Pink and purple in the image are from data collected by NASA’s Chandra X-ray Observatory. The golden stars were taken using the Hubble Space Telescope.
Studying something called polarization, which is all about how light waves move, can help scientists figure out how objects like pulsars send particles at fast speeds.
NASA’s Marshall Space Flight Center in Huntsville, Alabama are using an extreme object called Vela as a ‘laboratory’ to figure out the mysterious questions about astronomy, like how particles move close to the speed of light after certain stars explode. This technique is called IXPE (which stands for something else). According to Phil Kaaret, the lead scientist at NASA, IXPE could help us answer some important questions.
Recently, scientists conducted a study on the X-rays of Vela pulsar wind nebula and found out that it is highly polarized. They reported their findings in a journal called Nature in December.
Fei Xie, a professor at Guangxi University in China and former researcher at Italy’s National Institute for Astrophysics/Institute for Space Astrophysics and Planetology in Rome, said that they recently found the highest amount of polarization ever recorded in a space X-ray source.
The electromagnetic fields inside the pulsar wind nebula are lined up in certain directions, which means it’s highly polarized. Moreover, the X-rays detected by IXPE were created from electrons that spin around the magnetic fields of the nebula. If the X-rays are highly polarized too, it means those magnetic fields must be well organized.
Unlike some other X-ray sources, the high levels of polarization in this one suggest that the electrons weren’t sped up by normal “shock” movements. According to Roger W. Romani, a Stanford astrophysicist who studied the data from IXPE, some other process must be taking place. This could include something called “magnetic reconnection,” which happens when magnetic fields break apart and then regroup. This helps turn magnetic energy into particle energy.
The IXPE data show that the pulsar’s magnetic field forms like a smooth doughnut shape around its equator – just like scientists predicted.
“IXPE X-ray has made a big discovery about the Vela pulsar wind nebula which was missing before. Alessandro Di Marco from INAF/IAPS in Rome played an important part in confirming this data. IXPE X-Ray gave us an unprecedented view of the magnetic field at the core, showing that it matches with our findings from earlier radio images of the outer regions of this nebula.”
The Vela pulsar is really far away from us; it’s about 1,000 light-years away. It’s also quite small in size and its diameter is only about 15 miles or 25 kilometers. What’s even more amazing is that it can spin 11 times per second, faster than a helicopter rotor!
Scientists have recently made a discovery about the Vela pulsar wind nebula, which is a type of astronomical object. They found that when this object is observed using X-rays, it is polarized to almost the same degree as something called ‘synchrotron limit’. This was published in Nature on December 21st 2022.
IXPE is a NASA project and it launched in December 2021. It orbits way up high, about 595 kilometers (or 370 miles) away from the equator of Earth! NASA and the Italian Space Agency are working together on this mission, and they’ve got 13 countries helping out with their partners and science projects. Also, all the spacecraft operations are managed by Ball Aerospace in Colorado.
