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  • There's about to be a new star in our night sky | Space news from Ad Astra

There's about to be a new star in our night sky | Space news from Ad Astra

Also, here's how you de-ice a telescope from a million miles away

This week’s space news:

A new star is about to appear in the sky

T. Coronae Borealis is located about 3,000 light years away, and it’s a star with a magnitude of 10. That means it’s not visible to the unaided eye from Earth. But it’s going to get a lot brighter.

A regular nova from the Chandra X-Ray Telescope, credit: NASA

This star system is what’s called a recurrent nova on an 80-year cycle. This is a rare phenomenon, and scientists are still trying to figure out exactly what the mechanisms are behind it. Every 80 years, this star begins increasing in brightness, and then decreases. Then, 11 months later, it explodes and becomes much, much brighter. This brightness lasts a few days(though peak brightness will only last about 12 hours!), before the cycle starts all over again. It’s been documented since the year 1217 C.E., and the last time we witnessed the explosion was in the year 1946.

So, what might cause a star to explode over and over again on a regular cycle? The prevailing theory is that it’s due to the fact that the T. Coronae Borealis system is a binary with a white dwarf and a red giant. A white dwarf is what a star like the Sun will become one day, after it burns itself out — a dense, hot core with mass like our sun but packed into the size of Earth. A red giant, meanwhile, is a star like our sun that’s moved off the main sequence, in the later stages of its life. They’re huge, red, and relatively cool. 

(As an aside, there are some 400 known recurrent novas in the Milky Way, and what they all have in common is one of the stars is a white dwarf.)

These two stars are packed relatively close together, which means the white dwarf is collecting mass from the red giant. Remember, the white dwarf is already super dense so this continues to build pressure, and eventually, the hydrogen explodes. Unlike a supernova, though the star isn’t destroyed — just the material stolen from its red giant neighbor. Then the cycle starts all over again. 

Credit: NASA

Scientists think that T. Coronae Borealis could explode anytime between now and September, because the star was seen brightening in 2015, and then dipping in brightness in April 2023. But it could happen as late as next year — we don’t know, we just have to keep an eye on the sky.

Credit: NASA

It will appear in the Corona Borealis constellation, that’s surrounded by Hercules and Bootes (if you want to know more about the night sky, check out my book Stargazing, available wherever you buy books!), and the star will be as bright as Polaris in our night sky.

De-icing a telescope from a million miles away

Moving on to interesting telescope news, the ESA has to de-ice the Euclid telescope that’s located a million miles, or 1.5 million km, away.

Credit: ESA

The observatory, which is designed to study the mysteries of the dark universedark matter and dark energy — has tiny layers of water ice affecting its ability to observe light with its visible instrument. These are about the width of a strand of DNA. So the question is, how do you de-ice a telescope from a million miles, or 1.5 million km, away?

I want to make it clear — this is a common problem for space-based telescopes. This isn’t an indication something is broken, or has gone wrong. I’ve seen some headlines suggesting as such, and I do not want to contribute to that. But I think it’s interesting to highlight that this is something science and engineering teams have to deal with.

Credit: ESA

The first question is “this telescope is in space. Where is the water coming from?” Well, it’s water that was introduced through the air during its assembly on Earth. Now that Euclid is in the cold, dark vacuum of space, the components are releasing minuscule amounts of water. It’s generally not a problem unless the water ice ends up on the mission’s optical instruments — which is what happened. 

This is an anticipated problem, which is why Euclid underwent an outgassing after launch. The team warmed up the observatory using its heaters and the sun. This took care of any water molecules near Euclid’s surface, sublimating them into space. But there were additional molecules trapped in the spacecraft’s insulation, which surrounds the telescope, that’s now being released as water ice. 

VIS is the visible instrument, the white arrow is the path of light, Credit: ESA

Scientists first observed this problem because they saw a gradual decline in the amount of photons coming into Euclid’s visible instrument. They compared these readings to previous ones taken both by Euclid and Gaia, and because this was an expected problem, they determined that minuscule amounts of water ice were the culprit.

If Euclid weren’t such a sensitive telescope, this wouldn’t be a problem. But because even a few nanometers of ice is affecting it, it’s time to de-ice.

One option was to repeat the outgassing procedure that Euclid experienced after launch, and turn on all the heaters to melt the ice — but the problem is that would heat the entire spacecraft. It wouldn’t take long to cool the spacecraft back down, a week or so, but it could result in a slightly different optical alignment. With such a sensitive telescope, the ESA wanted to see if they could come up with a different solution to avoid weeks, possibly even months, of recalibration

One of Euclid’s first science images, credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi; CC BY-SA 3.0 IGO

Instead, they were trying to strategically warm up Euclid - flipping on heaters individually to see if that cleared the problem. The hope was that they could warm up specific low-risk parts of the spacecraft, which wouldn’t affect the visible instrument’s alignment, and regain the vision the instrument has lost. 

The good news is that after just one day of this, Euclid appears to be back to normal. The ESA is going to analyze the results and give more in-depth updates later, but this is a great sign — especially as this will continue to be a problem over Euclid’s lifetime, and they may have just found a great and efficient way to deal with the issue without affecting the rest of the spacecraft.

It’s worth noting that Euclid is out at Lagrange Point 2 the same place that JWST is — so why isn’t this an issue for JWST? That’s because JWST is infrared optimized and isn’t designed to observe the universe in visible light. (Euclid operates in both visible and infrared.) That means JWST is much, much colder than Euclid — it’s so cold that even the coldness of space isn’t enough. The mid-infrared instrument MIRI has its own separate cooling system.

JWST’s cold side, credit: STScI

When JWST started cooling following launch, the team used heaters to keep the near infrared instruments warmer than the cold-side structures, in order to prevent any water ice from forming. Once the cold side was cooled, they then began cooling the rest of the observatory. Critically, JWST does not have the same kind of insulation that Euclid has on its cold side where the instruments are. There is insulation, but it’s on the side with the solar panels, and the giant sunshield is in between the two, which is why this isn’t as big of an issue for JWST.

What does a map of 1 million black holes look like? 

Speaking of the sky, this week scientists released a map of 1.3 million active supermassive black holes across the universe. Called quasars, these are some of the brightest objects in the universe, thanks to the luminous gas and dust that surrounds them in an accretion disk (in a previous newsletter, I talked about what might be the brightest object in the universe — an active galactic nucleus, so check that out if you’re interested.)

So what does this kind of map look like? Here’s a visualization. The holes in the map are where the Milky Way’s disc blocks our view.

This map is unique because it’s three-dimensional, and it was built using data from the European Space Agency’s Gaia telescope. Gaia’s mission is to map the Milky Way, but thanks to its careful and methodical scanning, it also detects objects outside our galaxy. Scientists were able to use this secondary data from Gaia to create this map, but the original data from Gaia contained 6.6 million quasar candidates. They had to narrow it down  and confirm the distance to the quasars to create the map. If you want to read up on the process, the paper is in The Astrophysical Journal

It’s important to note, this isn’t the largest map ever compiled, but it’s the biggest by volume of the universe. Scientists have already used the map to study how the universe has expanded by looking at CMB, or cosmic microwave background, which is the first light of the universe after the Big Bang. 

The VERITAS mission to Venus is back!

Here’s some good news: the VERITAS mission to Venus is apparently back, after losing most of its funding in the FY 2024 budget. It’s a mission to map Venus’s surface to study why its planetary development was so different from Earth.

Credit: NASA/Magellan

Last week, I broke down some aspects of NASA’s FY 2025 budget request and talked about the bad news that unless something changed, the very important Chandra X-Ray Observatory would basically be cancelled. But there’s also some good news hidden in the planetary science budget.

VERITAS, the mission to Venus, appears to be back. VERITAS was chosen in 2021 as a Discovery mission (which is NASA’s program for smaller, lower cost solar system exploration missions) to orbit Venus. It was scheduled for 2027, but in late 2022, NASA delayed the mission by three years.

Screenshots of the Veritas FY 2024 and 2025 budgets from NASA

Basically, an independent review board uncovered problems with another mission, Psyche (which ended up launching in October of 2023) which were primarily due to understaffing and lack of oversight at NASA’s Jet Propulsion Laboratory, or JPL. They needed the funding from VERITAS to address the Psyche delay, so they delayed the Venus mission.

This doesn’t seem like a huge deal, except the delay was three years, and Psyche has already launched at this point. NASA did provide some funding for the science staff of the mission, but VERITAS was losing its engineering staff to other projects. It took 12 years for this mission to come together, with this set of personnel, and they were losing them because of NASA-JPL’s institutional issues. Basically, just not a great situation all around.

Credit: NASA

Well, now the good news: VERITAS is back in NASA’s planetary science budget. This supports a launch date in 2031 or 2032, which is amazing news because the U.S. hasn’t sent a spacecraft to specifically study Venus since NASA’s Magellan in 1990. The ESA did send Venus Express, which arrived in 2006 and had a fruitful eight-year mission.

The "devil comet” will stick around through the eclipse

Did you know you can see the horned devil comet right now, and it’ll stick around and give us a great show during the April 8 eclipse.

It’s less ominous than it sounds. The comet is called 12P/Pons-Brooks, and it’s currently visible with a pair of binoculars. Soon, you’ll be able to see it with the unaided eye. 

This comet’s nucleus is estimated to be 10.5 miles (17 km) across, and it’s been nicknamed the devil comet because of how it looks. Pons-Brooks has regular flares in brightness, and last July, it  had an outburst of gas and dust that made it 100 times brighter. The gas surrounding its nucleus, called a coma, expanded. Some thought it looked like devil horns, hence the name “devil comet.”

Credit: James Peirce/Flickr

We don’t know why Pons-Brooks occasionally flares in brightness, but one hypotheses is pretty cool — studying a different comet, 29P/Schwassmann‒Wachman, astronomer Richard Miles said that the outbursts might be the product of ice volcanoes, spewing frozen gases instead of lava into space. Miles thinks they occur because as a comet rotates during the day, its crust weakens, and then carbon monoxide builds up overnight. Pressure builds, and it’s eventually released through these cryoeruptions.

The comet will reach perihelion, when it’s closest to the sun, in late April, at which point it will be a magnitude of 4. That means it will be visible to the unaided eye. Now where it gets interesting is that this means it will be near the Sun when totality hits on April 8, 2024, across North America. If you’re in the path of the total eclipse, it’s very possible you will be able to see both the solar eclipse and this comet in the sky.

In launch news, Expedition 70….didn’t launch

Finally, in launch news, Expedition 70, with two cosmonauts and NASA astronaut Tracy Dyson was supposed to launch this morning, Thursday March 21, from Baikonur Cosmodrome but it didn’t. There was an abort at the 20-second mark before launch, which is really rare for a Soyuz. These are certainly old technology but they’re reliable, and while there have been issues in the past, it’s never during the launch countdown. I’m not going to say this is unprecedented, because I’m not familiar with every single crewed Soyuz launch, but I’m comfortable saying this is not normal.

It wasn't due to weather, and for awhile all we knew was that the cosmonauts and astronaut were safe.

We found out later that the issue was a "voltage drawdown of a chemical power source," so basically lower than expected power levels. Nothing too alarming, but it's just honestly weird to have an abort on a Soyuz lanuch sequence.

There’s a minimum of a 24-hour recycle on Soyuz hardware, and there’s another launch opportunity Saturday at 8:36 am ET, so hopefully they get off the ground safely at that point!