“Solitude” by Enceladus

Today’s digital palette cleanser is bought to you courtesy of Cassini and a small icy moon filled with intrigue.

As we constantly check the news sites for updates on the minutia of our daily lives, refresh our social media feeds, and ponder the existential dread that seems to be flooding our immediate future with increasing volume, it’s nice to find little islands of tranquility that appear out of nowhere. Today, I found that island in a beautiful processed image of Saturn’s moon Enceladus by the incredibly talented Kevin Gill, who works at NASA’s Jet Propulsion Laboratory:

[NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill]

In his tweet, Kevin simply describes this view as “solitude” and that’s pretty damn near perfect. In this image, the beautifully back-lit plumes are visible with the tenuous E-ring of Saturn creating an atmospheric backdrop.

Enceladus is a fascinating moon. During the NASA Cassini mission, which ended its glorious 13-year reign in Saturn orbit in 2017, the spacecraft became intimately familiar with the icy moon and its famous geysers. After flying through the plumes of water vapor, it became clear to mission scientists that not only does this 313 mile wide icy marble have an extensive subsurface liquid water ocean, that ocean contains organic molecules that could hint at astrobiological possibilities.

It’s sometimes nice to escape to Saturn orbit every now and again, so be sure to check out Kevin’s awe-inspiring Flickr album for more.

Nuking a Hurricane Is a Stupid Idea

Why have a hurricane when you could have a radioactive hurricane!

Hurricane Florence as seen from the International Space Station in September 2018 [NASA (edit by Ian O’Neill)]

Now, I don’t like to use the “s” word too often; it’s often misplaced and used to belittle someone’s lack of knowledge. A lack of knowledge doesn’t necessarily mean someone doesn’t want to learn, so to say an idea is stupid suggests someone is willfully ignorant. But this is one occasion where I’ll use “stupid” with a high degree of confidence that this idea is, well, very stupid:

President Trump has suggested multiple times to senior Homeland Security and national security officials that they explore using nuclear bombs to stop hurricanes from hitting the United States, according to sources who have heard the president’s private remarks and been briefed on a National Security Council memorandum that recorded those comments.

Axios

We’re now into year three of this administration’s willful ignorance of climate science, so it may not come as a surprise that the president doesn’t like to surround himself with many scientifically-savvy minds, lest their ideas get in the way of his administration’s damaging policies. So, while his statements may sound a little, shall we say, “extreme,” he’s coming from a place of ignorance and a horrible worldview that obsesses over detonating nuclear weapons to solve problems.

It’s easy for the science community to mock Trump’s comments as he often delivers these half-baked ideas with such bombastic enthusiasm that every day feels like an episode of The Twilight Zone, but it might come as a surprise to hear that he’s not the first to float the idea of nuking hurricanes. In fact, the idea of interrupting the convection currents of hurricanes over the Atlantic Ocean with nuclear blasts dates back to the Eisenhower era. And since then, the National Oceanic and Atmospheric Administration (which is a government body, I might add) regularly receives queries about going all Dr. Strangelove on the Atlantic.

During each hurricane season, there always appear suggestions that one should simply use nuclear weapons to try and destroy the storms. Apart from the fact that this might not even alter the storm, this approach neglects the problem that the released radioactive fallout would fairly quickly move with the tradewinds to affect land areas and cause devastating environmental problems. Needless to say, this is not a good idea.

NOAA

Fears of spreading radioactive fallout far and wide notwithstanding, if a nuke was actually effective at snuffing out a hurricane before it can even form, or at least redirect a powerful one from hitting Florida, say, wouldn’t the ends justify the means? In other words, if a deadly storm (capable of killing thousands) is averted, is a little bit of radiation really that bad? Well, yes, it is really bad, but nuking the ocean would be terribly ineffective hurricane mitigation effort.

As discussed by the NOAA, the amount of energy carried by a fully developed hurricane is huge and to interrupt or redirect a formed hurricane would require a lot of nuclear warheads detonating all the time.

The main difficulty with using explosives to modify hurricanes is the amount of energy required. A fully developed hurricane can release heat energy at a rate of 5 to 20×1013 watts and converts less than 10% of the heat into the mechanical energy of the wind. The heat release is equivalent to a 10-megaton nuclear bomb exploding every 20 minutes. According to the 1993 World Almanac, the entire human race used energy at a rate of 1013 watts in 1990, a rate less than 20% of the power of a hurricane.

NOAA

That’s not all: to concentrate the compression effects of the nuclear blasts on the central region of the cyclone to effectively dampen its sheer power, in a nutshell, simply isn’t possible.

OK then, why not drop a bomb on the weak tropical depressions (i.e. the seeds of hurricanes) to prevent them from growing in the first place? Well, that would be a crap-shoot. According to the NOAA, “[a]bout 80 of these disturbances form every year in the Atlantic basin, but only about 5 become hurricanes in a typical year.” There’s no obvious way of knowing which ones will ripen into that “killer” storm and, besides, we’d still need to dump a lot of nuclear energy into those depressions to stand a chance of stopping them.

Of course, these arguments sound reasonable; there are very few informed people who, after a little research, would doubt that firing nukes at weather systems is a stupid idea. But here we are, talking about the leader of the richest and most powerful nation on the planet wanting to wage a nuclear war on Mother Nature herself, while ignoring the very real science behind global warming (which, by the way, supercharges the ferocity of hurricanes) that is currently causing irreparable damage to our ecosystem.

What a time to be alive.

UPDATE (Aug. 26): Trump denies everything. In a baffling mix of third and first person, which leads me to believe it’s all true:

“Rolling Stones Rock” Is the Coolest Mars Rock That Ever Rolled

The legendary British rock band has been honored by NASA with a rock that the InSight lander rocket-blasted across the Red Planet’s surface last year.

[NASA/JPL-Caltech]

Those of you who frequently read my articles will know that I have a fascination with rolling rocks on celestial bodies. There’s the numerous boulders on the Moon that have been dislodged and rolled down crater sides, leaving their bouncy imprints in the dirt. There’s also the rolling rocks of Ceres. And the theorized rock tracks that are carved into Phobos. Then there’s Mars, the undisputed king of rolling boulders, imaged to beautiful precision by our orbiting armada of spacecraft.

The most famous rolling rock is no boulder, however; it’s barely larger than a golf ball—but it’s now the most famous pebble in the solar system. It’s a little rock that was minding its own business until a car-sized NASA robot rumbled through the Martian skies on Nov. 26, 2018, retro-rockets firing to slow its descent to the ground, that flipped the innocent ruddy bystander three feet (1 meter) from the landing site. It’s sobering to think that that rock probably hasn’t been disturbed for millions of years until that fateful day.

Behold, the “Rolling Stones Rock,” named after rock legends The Rolling Stones and announced tonight by Avengers actor Robert Downey Jr. to tens of thousands of Stones fans at the Rose Bowl Stadium, just before Mick Jagger, Keith Richards, Charlie Watts, Ronnie Wood, and friends rocked Los Angeles to its core. Space exploration doesn’t get much more Hollywood than this:

And a little animated introduction to the rock itself:

“The name Rolling Stones Rock is a perfect fit,” said Lori Glaze, director of NASA’s Planetary Science Division in Washington, in a statement. “Part of NASA’s charter is to share our work with different audiences. When we found out the Stones would be in Pasadena, honoring them seemed like a fun way to reach fans all over the world.”

While, in the grand scheme of things, naming a little rock after The Rolling Stones may not seem like such a big deal (and, besides, it’s an unofficial designation), as my wife and I stood watching the Stones do a blistering performance of “Sympathy For the Devil”, the family next to us were discussing Mars asking what the InSight lander was doing on the Red Planet.

So, mission success, NASA. Mission success.

“Cross-pollinating science and a legendary rock band is always a good thing…”

Robert Downey Jr.

The Rolling Stones and NASA Team Up for Some … Martian Shenanigans?

As the Stones arrive in Los Angeles to continue their No Filter tour, there’s a space-related twist in store at the Rose Bowl Stadium.

It’s been 25 years since the Rolling Stones played at the Rose Bowl Stadium, so SoCal fans of the legendary British rock band are understandably excited. But, for space fans, there’s a little something extra, as actor Robert Downey Jr. teased in a video he posted this morning:

So, what DOES the Rolling Stones, the Rose Bowl, NASA and Robert’s star sign (steady on now) have in common? As he’s an Ares, I’m thinking it’s Mars, a planet that NASA Jet Propulsion Laboratory (which is located near the Rose Bowl) knows more than a thing or two about. And the Stones have a song called “2,000 Light Years From Home”…? OK, I’m reaching a bit on the latter (besides, Mars is much closer to Earth than 2,000 light-years), but there’s definitely something a little Martian going on. Will Curiosity beep a Rolling Stones song from Mount Sharp? Has it got something to do with the upcoming NASA Mars 2020 mission? Will the Mars InSight lander make a cameo? Who knows. But I’m all for melding science with music, so I’m excited.

And I’ll be there to cover the event, so keep an eye on @astroengine on Twitter and Instagram for updates!

Space Telescope Sees a Rocky Exoplanet’s Surface. And It’s Horrible

It’s both too hot and too cold, has no atmosphere, and is no place to take a vacation—but there is an upside.

Artist’s impression of LHS 3844b, which is thought to be covered in dark lava rock with no atmosphere. It’s difficult to see any upside [NASA/JPL-Caltech/R. Hurt (IPAC)]

It’s hard to say anything positive about the exoplanet LHS 3844b. It’s a wretched place; an alien world that orbits its tiny star in less than half a day. As it’s so close to its red dwarf star, it’s tidally-locked—when one side of the planet is always in baking daylight, the other side is in a perpetual frozen night. Oh, and it doesn’t even have an atmosphere.

Why the heck am I even writing about this unfortunate celestial object?

Well, it might not be our idea of an interstellar getaway, but it is remarkable for two profound reasons: It’s a rare look at the surface conditions of a rocky exoplanet orbiting a distant star, and the very fact that astronomers are confident it doesn’t have an atmosphere is a really big deal.

World of Extremes

Discovered in 2018, LHS 3844b is located nearly 49 light-years away. It has a radius 30 percent larger than Earth and orbits a cool M dwarf star. It was detected by NASA’s newest space-based exoplanet hunter, the Transiting Exoplanet Satellite Survey (TESS); every 11 hours, the world drifts in front of the star, blocking a tiny amount of light (and event known as a “transit”) that can be detected by TESS. As it orbits so close to its host star, it’s glowing bright in infrared radiation, giving the researchers of a new study published in Nature an incredible opportunity.

Using observational data from NASA’s Spitzer space telescope, which views the universe in infrared wavelengths, and as the star is comparatively cool and dim, the researchers could discern how much infrared radiation was being emitted from the exoplanet’s “day” side and calculated that it must be cooking at a temperature of 1,410 degrees Fahrenheit (770 degrees Celsius). On measuring the infrared emissions from the exoplanet’s dark side, they realized that the heat from the day side wasn’t being transported to the night side. On Earth, our atmosphere distributes thermal energy around the globe, ensuring that the night and day sides’ temperature difference isn’t so extreme. LHS 3844b, however, isn’t distributing any of its thermal energy creating a sharp drop-off in temperature between both hemispheres. In other words: no atmosphere!

“The temperature contrast on this planet is about as big as it can possibly be,” said Laura Kreidberg, a researcher at the Harvard and Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead author of the new study. “That matches beautifully with our model of a bare rock with no atmosphere.

“We’ve got lots of theories about how planetary atmospheres fare around M dwarfs, but we haven’t been able to study them empirically. Now, with LHS 3844b, we have a terrestrial planet outside our solar system where for the first time we can determine observationally that an atmosphere is not present.”

This exoplanet has about as much atmosphere as the planet Mercury or our Moon, and it shares some other traits too. By measuring the amount of starlight the exoplanet reflects (a characteristic known as “albedo”), Kreidberg’s team also took a stab at understanding its composition.

As the world is “quite dark,” they deduced that it’s very likely that it’s covered in basalt (volcanic rock), the same stuff that we find in the crusts of the Moon and Mercury. “We know that the mare of the Moon are formed by ancient volcanism,” said Renyu Hu, an exoplanet scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., “and we postulate that this might be what has happened on this planet.”

An Atmospheric Problem

Red dwarfs are known to play host to entire systems of exoplanets, including many small rocky worlds of similar dimensions as Earth. Many of these worlds have been found within the much-hyped “habitable zone”, where it’s neither too hot or too cold for liquid water to persist. As we probably are all aware, liquid water is super helpful for life (on our planet, at least) to evolve. While LHS 3844b could never be considered “habitable” in any way, shape or form, the fact that it doesn’t have an atmosphere may be very revealing.

It’s simply not good enough to find a habitable zone exoplanet that orbits a red dwarf and say “there’s a good chance that aliens live there!” Even though it has the right temperature, because it’s orbiting a red dwarf and likely tidally-locked could mean these types of worlds are devoid of atmospheres, a serious wrench in the hope that all habitable zone exoplanets have the same likelihood of life. That’s not to say all red dwarf-orbiting exoplanets lack atmospheres, but now at least we are developing techniques that could, one day, help us from the atmospheric potential of more “habitable” candidates.

I, For One, Welcome Our New Tardigrade Overlords

“One small step for (a) water bear, one giant leap for water-dwelling eight-legged segmented micro-animals.” —Teddy Tardigrade

Tardigrades are everywhere. And now they’re on the Moon [Public Domain]

Are you thinking what I’m thinking? Because if you are, you’re thinking that exposing tardigrades to high-energy cosmic rays can only mean one thing: super-tardigrades. From Live Science:

The Israeli spacecraft Beresheet crashed into the moon during a failed landing attempt on April 11. In doing so, it may have strewn the lunar surface with thousands of dehydrated tardigrades, Wired reported yesterday (Aug. 5). Beresheet was a robotic lander. Though it didn’t transport astronauts, it carried human DNA samples, along with the aforementioned tardigrades and 30 million very small digitized pages of information about human society and culture. However, it’s unknown if the archive — and the water bears — survived the explosive impact when Beresheet crashed, according to Wired.

Mindy Weisberger, Senior Writer

Well, OK, as tough as they are, it’s probably unlikely that those microscopic explorers will re-hydrate any time soon before being hit by high-energy particles that will then endow the tiny guys with Marvel-like superpowers, but it’s nice to dream.

But what are tardigrades? Let’s go back to Mindy’s Live Science article, because her explanation is simply too adorable not to reprint:

Tardigrades, also known as moss piglets, are microscopic creatures measuring between 0.002 and 0.05 inches (0.05 to 1.2 millimeters) long. They have endearingly tubby bodies and eight legs tipped with tiny “hands”; but tardigrades are just as well-known for their near-indestructibility as they are for their unbearable cuteness.

Moss piglets! Or should we now say moon piglets?

Light-hearted tardigiggles aside, it’s hard not to feel sorry for the tiny sleeping creatures. In a dehydrated state, they can remain hibernating (I’m not sure if that’s the correct term for being freeze-dried, but let’s go with hibernating) for a decade (!) while they wait for water to appear so they can go about their tardigradey business. They’ve been discovered in just about every environment on Earth, are extremely resilient and can even survive in space without a tiny spacesuit to keep them warm. In short, they’re pretty amazing. And now they’re on the Moon, which may or may not be a good thing (there’s a lot of cosmic rays up there).

Bonus: I’ll close with a short story:

Tonight’s “Black Moon” Isn’t Actually a Thing

The media strikes again.

Ahhh the glorious Black Moon. Seriously, it’s there. [via NASA-SVS]

Who doesn’t love the moon? You just have to look up when the skies are clear and there it is, our lunar friend, doing its thing, changing phases, yanking at our oceans, inspiring the world to look “up.”

It’s little wonder, then, that humanity has created many different names for our planet’s tidal partner in crime. There are useful astronomical names that describe its different phases (new/full, first/third quarter, waxing/waning crescent/gibbous), but there’s also other names that have popped up throughout human history that relate to other subtleties in the lunar dance around our world. A quasi-rare second full moon of the month? Blue moon! When the full moon coincides with perigee (lunar close approach with Earth)? Supermoon! When you get a bonus lunar combo that includes a full moon, a supermoon… and the Earth is blocking the sun so we have a lunar eclipse… and it all happens to occur in January?? That’s a SUPER BLOOD WOLF MOON ECLIPSE! Because of course it is.

As you may or may not have realized, humans—particularly humans in marketing departments, the media, and astrologers with too much time on their hands—like to label things. Some of these labels can be useful, others not so much. Many are, frankly, just plain silly. Which brings me to today’s lunar branding non-event: The Black Moon. Ohh sounds… eerie.

Over to Joe Rao at SPACE.com:

As one who has been involved in the broadcasting field for nearly 40 years, I’d like to point out that we live in a time when the news media is seemingly obsessed with “branding.” This marketing strategy involves creating a differentiated name and image — often using a tagline — in order to establish a presence in people’s mind. In recent years in the field of astronomy, for example, we’ve seen annular eclipses — those cases when the moon is too small to completely cover the disk of the sun — become branded as “Ring of Fire” eclipses. A total eclipse of the moon — when the moon’s plunge through the Earth’s shadow causes the satellite to turn a coppery red color — is now referred to as a “Blood Moon.” 

When a full moon is also passing through that part of its orbit that brings it closest to Earth — perigee — we now brand that circumstance as a supermoon. That term was actually conjured up by an astrologer back in 1979 but quite suddenly became a very popular media brand after an exceptionally close approach of a full moon to Earth in March 2011. It surprises me that even NASA now endorses the term, although it seems to me the astronomical community in general shies away from designating any perigee full moon as “super.”

Then there is Blue Moon. This moniker came about because a writer for Sky & Telescope Magazine misinterpreted an arcane definition given by a now-defunct New England Almanac for when a full moon is branded “blue,” and instead incorrectly reasoned that in a month with two full moons, the second is called a Blue Moon. That was a brand that quietly went unnoticed for some 40 years, until a syndicated radio show promoted the term in the 1980s and it then went viral. So now, even though the second full moon in a month is not the original definition for a Blue Moon, in popular culture we now automatically associate the second full moon in a calendar month with a Blue Moon.

So are you ready for yet another lunar brand? The newest one is Black Moon.

Joe Rao, “Black Moon 2019: What It Is (and Why You Can’t See It)“, SPACE.com

That’s a very polite way of saying, “it’s all bullshit, really.”

So, what IS a Black Moon? Well, it’s the opposite of a Blue Moon, as in it’s the second New Moon in the month of July and a New Moon is when the sun, moon and Earth are in almost exact alignment; the entire Earth-facing side of the moon is in complete shadow. The upshot is you can’t see it. It’s a naked-eye astronomical non-event.

Having said that, should the moon exactly line up with the sun, you get a solar eclipse—arguably the most mind-blowing astronomical event we can see on Earth. A plain ol’ Black Moon? Not so much.

UPDATE: As this post turned into the seed for a fun little online discussion, I added some thoughts in the following Twitter thread. Feel free to @ me:

When a Climate Emergency Turns Into a Human Catastrophe

There’s nothing subtle about this deadly consequence of global warming.

[Pexels]

While the recent record-breaking temperatures in Europe have grabbed the headlines, it’s worth remembering that such record-shattering heatwaves are nothing new to other regions of the planet. And many of those regions are fast approaching a grim reality: heat events that will overwhelm the body’s ability to function.

From “Heatwave: think it’s hot in Europe? The human body is already close to thermal limits elsewhere“:

Once this wetbulb temperature threshold is crossed, the air is so full of water vapour that sweat no longer evaporates. Without the means to dissipate heat, our core temperature rises, irrespective of how much water we drink, how much shade we seek, or how much rest we take. Without respite, death follows – soonest for the very young, elderly or those with pre-existing medical conditions.

Wetbulb temperatures of 35°C have not yet been widely reported, but there is some evidence that they are starting to occur in Southwest Asia. Climate change then offers the prospect that some of the most densely populated regions on Earth could pass this threshold by the end of the century, with the Persian GulfSouth Asia, and most recently the North China Plain on the front line. These regions are, together, home to billions of people.

Tom Matthews, Climate Scientist, Loughborough University, The Conversation.

Matthews goes on to warn of “grey swan” events (read his research here, via Nature Climate Change), where overwhelming heat and moisture is coupled with mass power outages triggered by anthropomorphic global warming-boosted extreme weather events to leave vast populated regions physically unable to keep cool.

While many effects of climate change may seem subtle or “something for future generations to worry about,” this extreme situation will happen sooner rather than later, and as Matthews discusses, it has probably already been experienced.

Any debate about the realities of climate change is a distant dot in the rear-view mirror, and, according to a recent study, the scientific consensus that humans are driving global warming has passed 99 percent. (In reality, the consensus that humans are causing the planet to heat up has been an overwhelming majority for years, likely decades.)

Sadly, scientific consensus isn’t enough to stymie the emissions of greenhouse gasses—if it was, the oil rigs and coal mines would have been shut down years ago. It’s the human disposition for greed and myopic politics that will turn this once ecologically-diverse planet into an increasingly inhospitable place for humans to thrive.

The pushback has been political rather than scientific. In the US, the rightwing thinktank the Competitive Enterprise Institute (CEI) is reportedly putting pressure on Nasa to remove a reference to the 97% study from its webpage. The CEI has received event funding from the American Fuel and Petrochemical Manufacturers and Charles Koch Institute, which have much to lose from a transition to a low-carbon economy.

Johnathan Watts, The Guardian

Policy makers who claim to be “skeptical” about the overwhelming scientific consensus that humans are causing global warming aren’t necessarily uneducated fools. They simply do not care. Democracy has long been hijacked by special interest groups and corporations that care little about the future health of the environment and society. In the long run, their belligerent self-interest will undercut their bottom line. It won’t be long until our carbon-driven economy will collapse under the weight of relentless impacts caused by the continued burning of fossil fuels.

It’s the ultimate self-own, and it’s a shame they’ll take us with them.

Two Stellar Zombie Spinners Are Ripping Up Spacetime

The pair of white dwarf stars are orbiting one another every seven minutes—and future gravitational wave observatories will be able to detect them whirl.

White dwarf binaries are among some of the most fascinating star systems known, and a newly discovered compact binary, located some 8,000 light-years away in the constellation Boötes, has taken the exotic nature of these systems to new spacetime-warping extremes.

The extremely compact eclipsing binary, called ZTF J1530+5027, is one of the most extreme white dwarf systems known to exist [Caltech/IPAC]

Astronomers using Caltech’s Zwicky Transient Facility (ZTF), a precision sky survey at Palomar Observatory near San Diego in Southern California, made the discovery of ZTF J1530+5027 by detecting the dimming effect caused by one of the stars passing in front of the other. Known as an “eclipsing binary,” the cooler (and therefor dimmer) white dwarf blocks the starlight of the hotter (and brighter) star, causing the ZTF to register a periodic dimming event. This dimming occurs once every seven minutes, meaning they are zipping around each other at speeds of hundreds of miles per second! It is the second fastest white dwarf binary known and the most rapid eclipsing binary discovered in our galaxy. The fortunate alignment allows astronomers to not only precisely measure their orbital speed, they can also gauge the stars’ sizes and masses.

White dwarfs are the stellar corpses of sun-like stars that ran out of fuel long ago. Our sun will become a white dwarf in around five billion years, after it has exhausted its hydrogen fuel that maintains fusion in its core. A short period after, it will swell into a red giant (possibly expanding out as far as Earth, incinerating it) and then lose its plasma to space via powerful solar winds. All that will be left of our once glorious star will be a planetary nebula and a tiny and dense white dwarf, approximately the size of our planet, spinning in the middle. The two white dwarfs in ZTF J1530+5027 likely passed through their red giant phase at different times, but now they’re stuck, in a perpetual death spiral that spells doom for one of the objects.

To fully realize just how crazy-extreme this white dwarf binary is, they are only separated by one-fifth of the distance that the moon orbits Earth, meaning both stars would fully fit inside Saturn. They have a combined mass of our entire sun. As they orbit so snugly, it’s likely that the more massive star will start to tidally drag material from the other, cannibalizing it.

“Matter is getting ready to spill off of the bigger and lighter white dwarf onto the smaller and heavier one, which will eventually completely subsume its lighter companion,” said Kevin Burdge, Caltech graduate student and lead author of a study published in the journal Nature. “We’ve seen many examples of a type of system where one white dwarf has been mostly cannibalized by its companion, but we rarely catch these systems as they are still merging like this one.”

While impressive, the real fireworks are invisible—the stars are ripping up spacetime, generating gravitational waves that are sapping energy from the system, hastening the binary’s ultimate demise. What’s more, astronomers are anticipating that the future Laser Interferometer Space Antenna (LISA), which is scheduled for launch by the European Space Agency in 2034, will be able to detect its gravitational pulse.

“These two white dwarfs are merging because they are emitting gravitational waves,” added collaborator Tom Prince, a senior research scientist at Caltech and NASA’s Jet Propulsion Laboratory (JPL, in Pasadena, Calif. “Within a week of LISA turning on, it should pick up the gravitational waves from this system. LISA will find tens of thousands of binary systems in our galaxy like this one, but so far we only know of a few. And this binary-star system is one of the best characterized yet due to its eclipsing nature.”

This system is expected to keep blinking from our perspective for another hundred thousand years, but how will the system ultimately go kaput? Well, the researchers aren’t entirely certain. On the one hand, the more massive white dwarf may suck the other dry like a vampiric parasite, consuming all of its matter until only one, well-fed star remains. Alternatively, the act of cannibalization may cause the reverse; as mass is transferred to one star, the other may be flung outward to a wider orbit, increasing their orbital period.

“Sometimes these binary white dwarfs merge into one star, and other times the orbit widens as the lighter white dwarf is gradually shredded by the heavier one,” said co-author Jim Fuller, an assistant professor at Caltech. “We’re not sure what will happen in this case, but finding more such systems will tell us how often these stars survive their close encounters.”

One early mystery about this extreme binary is the question of X-rays, or lack thereof. The more massive star is really hot, with a temperature nine times that of the sun (50,000 Kelvin). The researchers believe that this is because it has already begun pulling material from its partner, an act that accelerates and heats the plasma that is being stolen, starting to create an accretion disk. But the accreting gas should be so hot that the system would be humming in X-rays, but it isn’t. “It’s strange that we aren’t seeing X-rays in this system. One possibility is that the accretion spots on the white dwarf—the areas the material is falling on—are bigger than what is typical, and this could result in the emission of ultraviolet light and optical light instead of X-rays,” added Burdge.

[Caltech/IPAC]

It’s exciting to think what the next generation of gravitational wave observatories (particularly LISA that will be sensitive to extremely weak spacetime ripples from systems such as these) combined with traditional (re: electromagnetic) observatories will herald for the future of astronomy. Like the emerging “multi-messenger” era for astronomy that combines observations of the electromagnetic spectrum and gravitational wave signals to confirm short gamma-ray bursts are triggered by neutron star collisions, it’s going to blow our minds when we can access more subtle gravitational wave sources such as these and directly see the gravitational energy leaking from compact binaries.