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First traces of atmospheric water vapour detected on 'super-Earth' in habitable zone – CBC.ca

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Roughly 111 light-years away, toward the constellation of Leo, lies a dim star less than half the mass of our sun, with two planets in close orbit. Now, astronomers have revealed that one of those planets has an atmosphere containing water vapour.

The discovery, published Wednesday in the journal Nature, is the first of its kind. While other, larger, gaseous planets — called hot Jupiters — have revealed some hints about the chemical elements contained in their atmospheres, this is the first time water vapour has been detected on a potentially habitable planet, an historic first.

The planet is called K2-18 b, and orbits its parent star — K2-18 — at roughly 0.14 astronomical units (one AU is the distance from our sun to Earth). Because it is so much closer to its parent star, it orbits quite quickly: one year on K2-18 b is equal to just 33 days here on Earth.

K2-18 b is roughly eight times the mass of Earth and about twice the radius, making it a super-Earth or sub-Neptune in the somewhat loose classification of exoplanets.

But what’s most important is that K2-18 b resides within the star’s habitable zone, a region around a star where liquid water can exist on a planet’s surface. Depending on what kind of star it is, the distance varies. In this case, K2-18 b orbits the dwarf star within what would be Mercury’s orbit in our solar system. 

The search is on

K2-18 b was discovered in 2015, and due to its proximity to Earth and its dim star, it was considered a good candidate for detecting an atmosphere. The team of astrophysicists examined data from the Hubble Space Telescope collected in 2016 and 2017. While not ideal for detecting a wide range of molecular elements in distant exoplanets, Hubble is, however, capable of detecting water vapour. 

Astronomers made the discovery of atmospheric water vapour in K2-18 b’s atmosphere using 2016 and 2017 data from the Hubble Space Telescope. (NASA)

The team additionally used spectroscopic data (where light is broken up into its particular molecular elements). What they found was strong evidence that K2-18 b had water vapour in its atmosphere.

Running several models, they concluded that three conditions were equally likely to account for the water vapour detected: that it could be a type of “waterworld,” with an abundance of water; that it could contain gases such as hydrogen and nitrogen, with a little water; and finally, that it could contain very little water, but with high-altitude clouds.

Those three models mean that the water that was detected could range from 0.01 per cent to 50 per cent.

It’s a large range, to be sure.

“We don’t really know how much water there is,” said Angelos Tsiaras, lead author of the study. “This is related to the size of the atmosphere. We need wider wavelengths to cover it.”

Hubble finds water vapour on distant exoplanet

[embedded content]

While Hubble may only be able to scan narrow wavelengths in its observations, a new space telescope is set to revolutionize astronomy: the James Webb Space Telescope. That, the authors say, may blow the search for atmospheres around potentially habitable exoplanets wide open.

One small step

The detection of water vapour around a potentially habitable planet is being hailed as a first step in what will become a wider understanding of exoplanets.

“The first evidence for an atmospheric feature in a habitable-zone planet is just fantastic,” said exoplanetary researcher Ryan Cloutier of the Center for Astrophysics at Harvard University. As a PhD student at the University of Toronto, he lead the research that not only determined that K2-18 b was a super-Earth, but that there was another planet in the system. “Habitable-zone planets are the holy grail for atmospheric studies.”

Exoplanets that are Jupiter-sized or larger are easier to find than smaller ones, particularly those closer to the size of Earth. So, if simply finding them is so challenging, determining the molecules in their atmospheres is even more difficult. 

But finding water vapour alone in an atmosphere of a potentially habitable exoplanet doesn’t mean life exists on K2-18 b. 

And water vapour doesn’t necessarily mean water exists on the surface. 

The temperature of the planet is roughly –73 C to 46 C, which is similar to Earth. The range is so large because of various unknown factors, including the temperature of the star and the distance between the star and the planet and the planet’s atmosphere and pressure, which is why it’s unclear if water exists on the surface.

However, the James Webb Space Telescope — which is scheduled to launch in 2021 — will be capable of finding other molecules such as methane and ozone, which could add more evidence to the potential of life on an exoplanet, though it won’t be definitive proof of life.

The James Webb Space Telescope is the scientific successor to NASA’s Hubble Space Telescope, and is scheduled to launch in 2021. (NASA/Desiree Stover)

“I think it’s very cool, and it’s a step in the right direction. These objects are incredibly enigmatic, the so-called sub-Neptunes … and we have no idea what they are,” said Sara Seager, an MIT exoplanet researcher originally from Toronto, who was not involved in the study. “We really want to understand this type of planet, and we’re hoping the atmospheres will provide some clue as to what they are.”

Tsiaras is optimistic about the future of exoplanet habitability research.

“It’s always one small step at a time,” said Tsiaras. “This time it was the first atmosphere, then it will be the first methane, then probably, why not, some detection of ozone. So one small step at a time.”

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SpaceX's Next Starship Prototype Taking Shape (Photos) – Space.com

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SpaceX’s next Starship prototype won’t be just a concept vehicle for much longer.

Construction of the test craft is proceeding apace, as two new photos posted on Twitter today (Sept. 17) by company founder and CEO Elon Musk reveal. 

One of the images shows the vehicle — apparently Starship Mk1, which is being assembled at SpaceX’s South Texas facility, near the village of Boca Chica — in the background, standing behind a building that contains a variety of parts and other equipment. (SpaceX is also building a similar prototype, called Starship Mk2, at the company’s Florida facilities, reasoning that a little intracompany competition will improve the vehicle’s final design.)

Related: SpaceX’s Starship and Super Heavy Mars Rocket in Pictures

“Droid Junkyard, Tatooine,” Musk said via Twitter, referring to Luke Skywalker’s home planet in the “Star Wars” movies. 

The other photo is a close-up view of a ring-shaped section being lowered onto the Mk1’s body. The billionaire entrepreneur had a joky caption for this one as well: “Area 51 of Area 51.”

The Mk1 and Mk2 follow in the footsteps of SpaceX’s Starhopper vehicle, which was retired after acing a big test flight last month. But the new vehicles are far more ambitious and more capable. Whereas Starhopper sported just a single Raptor engine and stayed within a few hundred feet of the ground, for example, the Mk1 and Mk2 will be powered by at least three Raptors and will go much higher.

SpaceX is aiming for a test flight that gets 12 miles (20 kilometers) up in October, followed by an orbital attempt “shortly thereafter,” Musk said late last month.

All of these steps are leading toward the final Starship, SpaceX’s planned Mars-colonizing craft. That Starship will be capable of carrying 100 passengers and will launch atop a huge rocket called the Super Heavy. Both of the elements, rocket and spaceship, will be fully and rapidly reusable, Musk has said.

The final Starship, as currently envisioned, will sport six Raptors, while the Super Heavy will be powered by 35 of the engines. Those numbers could change, however; Musk is scheduled to give a Starship design update on Sept. 28 from the South Texas site.

The Mk1 should be fully assembled by that time, he has said.

The Mk1 and Mk2 test campaigns won’t be terribly lengthy, if SpaceX’s planned schedules hold. Company representatives have said that the first operational flights of Starship, which are likely to be commercial satellite launches, could come as early as 2021. (Eventually, SpaceX plans to use Starship for all the company’s spaceflight needs, from interplanetary colonization missions to satellite launches to point-to-point trips around Earth.)

And SpaceX is targeting 2023 for a crewed mission of the vehicle: a flight around the moon booked by Japanese billionaire Yusaku Maezawa.

Mike Wall’s book about the search for alien life, “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook

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Could We Intercept Interstellar Comet C/2019 Q4 Borisov? – Universe Today

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When ‘Oumuamua passed through our Solar System two years ago, it set off a flurry of excitement in the astronomical community. Here was the first-ever interstellar object that be observed by human trackers, and the mysteries surrounding its true nature and composition led to some pretty interesting theories. There were even some proposals for a rapid mission that would be able to rendezvous with it.

And now that a second interstellar object – C/2019 Q4 (Borisov) – has been detected traveling through the Solar System, similar proposals are being made. One of them comes from a group of scientists from the Initiative for Interstellar Studies (i4is) in the UK. In a recent study, they assess the technical feasibility of sending a mission to this interstellar comet using existing technology, and found that there were a few options!

In many ways, C/2019 Q4 (Borisov) represents an opportunity to conduct the kinds of research that were not possible with ‘Oumuamua. When that mystery object was first observed, it had already made its closest pass to the Sun, past Earth, and was on its way out of the Solar System. Nevertheless, what we were able to learn about ‘Oumuamua led to the conclusion that it was an entirely new class of celestial object.

Artist’s impression of the first interstellar asteroid/comet, “Oumuamua”. This unique object was discovered on Oct. 19th, 2017, by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

In addition to those who ventured that it was either a comet or an asteroid, there were also those who theorized that ‘Oumuamua could be a fragment from a comet that exploded when passing close to our Sun, or even an extra-terrestrial solar sail. Another interesting find was the fact that similar objects likely pass through our Solar System on a regular basis (many of which stay).

For these reasons, a mission that could study such objects up close is very desirable. As Dr. Andreas M. Hein – the executive director of i4is’s board of directors, the chairman of its Technical Research Committee, and one of the co-authors on the recent study – told Universe Today via email:

“Investigating interstellar objects from a close distance would provide us with unique data about other star systems without actually flying to them. They might provide unique insights into the evolution and composition of other star systems and exoplanets in them. Interstellar objects are cool as it’s a bit like: If you can’t go to the mountain, let the mountain come to you. It will likely take many decades until we can send a spacecraft to another star. Hence, interstellar objects might be an intermediate solution for finding out more about other stars and their planets.”

What’s more, he claims, these objects have probably been travelling between star system for hundreds of thousands (or even millions) of years. As a result, they undoubtedly picked up material along the way or bear the marks of encounters with other objects or forces. In short, their composition and surface features can tell us a great deal about what is out there in the interstellar medium.

Artist’s illustration of a light-sail powered by lasers generated on the surface of a planet. Credit: M. Weiss/CfA

This is not the first time that i4is has proposed sending a spacecraft to rendezvous with an interstellar object. In 2017, Dr. Hein and several colleagues from i4is (who also co-authored this study) produced a paper titled “Project Lyra: Sending a Spacecraft to 1I/’Oumuamua (former A/2017 U1), the Interstellar Asteroid“, which was conducted with the help of the asteroid-prospecting company Asteroid Initiatives LLC.

The project was so-named because of ‘Oumuamua’s origins, which astronomers concluded came from the general direction of Vega – the brightest star in the northern constellation of Lyra. After taking into account the speed with which ‘Oumuamua was leaving the Solar System at the time – 26 km/s (93,600 km/h; 58,160 mph) – they determined that any proposal would be a trade-off between three factors.

These included when a mission could launch, the velocity it could achieve, and the time it would take to rendezvous with the object. Under the circumstances, they felt that the best option was to wait for future technological breakthroughs – such as those being pursued by Breakthrough Starshot (a concept for a laser-driven interstellar solar sail).

These conclusions have proven very applicable, thanks to the detection of a second interstellar object passing through our Solar System in as many years. In their most recent study, the research team once again used Optimum Interplanetary Trajectory Software (OITS) – which was developed by team-member Adam Hibberd – to assess all available options for sending a spacecraft to rendezvous with an interstellar object.

The Falcon Heavy's first flight. Each time the Heavy lifts off, it uses roughly 440 tons of fuel. Image: SpaceX
The Falcon Heavy’s first flight. Each time the Heavy lifts off, it uses roughly 440 tons of fuel. Image: SpaceX

These included the optimal launch vehicle (like NASA’s Space Launch System (SLS) or SpaceX’s Falcon Heavy) the optimal trajectory for the mission, and the best type of spacecraft. In the end, they determined that humanity has the capability of rendezvousing with an interstellar object using existing technology and came up with a mission architecture that could make that happen.

This mission would rely on a heavy-launch vehicle and could alternately employ a 2 ton (1.8 metric ton) or a 3 kg (6.6 lbs) CubeSat spacecraft. Depending on when it launched and what its preferred trajectory would be, it might also need to conduct a Jupiter flyby and Solar Oberth maneuver to catch up with C/2019 Q4 (Borisov). As Dr. Hein explained:

“Our results show that for both, ‘Oumuamua and C/2019 Q4 (Borisov), we already have the technology to visit these objects. Regarding ‘Oumuamua, we can launch a spacecraft towards it even beyond the year 2030. There is plenty of time to develop such a spacecraft. The case for C/2019 Q4 (Borisov) is a bit more tricky, as it is faster than ‘Oumuamua. But even for this object, we could have sent a two-ton spacecraft to it with a Falcon Heavy, if we would have launched it in 2018.”

“Later missions are also possible, but require a bigger launcher. Future telescopes will be able to detect such objects much earlier and with adequate preparation, we can send a spacecraft on an encounter mission. So we have the technology to do this and with the discovery of C/2019 Q4 (Borisov), we also know that we probably have plenty of opportunities to fly to such an object.”

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

Once again, the presence of an interstellar object in our Solar System is a major source of excitement. In addition to all the opportunities to learn from them, C/2019 Q4 and ‘Oumuamua are encouraging because of the implication their presence has. Not only do they confirm that objects from distant stars pass through our System pretty regularly; they also show that we are at a point where we can detect, track and study them.

But knowing that in the future, we will be able to study them up close is especially exciting! In fact, the ESA is currently working on a mission that could very be the one to rendezvous with a future interstellar object. It’s known as the Comet Interceptor, a “fast-class” concept consisting of three spacecraft that will wait in space until a pristine comet appears, rapidly catch up with it!

“We imagine two types of research,” Dr. Hein said. “First, remote-sensing, for example with a telescope taking pictures. Second, we can analyze material from the object directly by shooting an impactor into it and catching some of the particles from the dust plume which is generated with the main spacecraft. This would provide unique insights into the composition of the object.”

As for what this research could reveal, Dr. Hein has some thoughts on that too: “I can only speculate but we might see evidence that organic molecules, the building blocks for life, actually travel between star systems and who knows, maybe life itself might actually spread between stars in our galaxy.”

Further Reading: arXiv

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Physicists at MIT Shave Estimate of Mass of Neutrino “Ghost Particle” in Half – SciTechDaily

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KATRIN’s spectrometer, shown here, precisely measures the energy of electrons emitted in the decay of tritium, which has helped scientists come closer to pinning down the mass of the ghost-like neutrino. Credit: The KATRIN Collaboration

Joseph Formaggio explains the discovery that the ghostly particle must be no more than 1 electronvolt, half as massive as previously thought.

An international team of scientists, including researchers at MIT, has come closer to pinning down the mass of the elusive neutrino. These ghost-like particles permeate the universe and yet are thought to be nearly massless, streaming by the millions through our bodies while leaving barely any physical trace.

The researchers have determined that the mass of the neutrino should be no more than 1 electron volt. Scientists previously estimated the upper limit of the neutrino’s mass to be around 2 electron volts, so this new estimate shaves down the neutrino’s mass range by more than half.

The new estimate was determined based on data taken by KATRIN, the Karlsruhe Tritium Neutrino Experiment, at the Karlsruhe Institute of Technology in Germany, and reported at the 2019 Conference on Astroparticle and Underground Physics last week. The experiment triggers tritium gas to decay, which in turn releases neutrinos, along with electrons. While the neutrinos are quick to dissipate, KATRIN’s sequence of magnets directs tritium’s electrons into the heart of the experiment — a giant 200-ton spectrometer, where the electrons’ mass and energy can be measured, and from there, researchers can calculate the mass of the corresponding neutrinos.

Joseph Formaggio, professor of physics at MIT, is a leading member of the KATRIN experimental group, and spoke with MIT News about the new estimate and the road ahead in the neutrino search.

Q: The neutrino, based on KATRIN’s findings, can’t be more massive than 1 electron volt. Put this context for us: How light is this, and how big a deal is it that the neutrino’s maximum mass could be half of what people previously thought?

A: Well, that’s somewhat of a difficult question, since people (myself included) don’t really have an intuitive sense of what the mass is of any particle, but let’s try. Consider something very small, like a virus. Each virus is made up of roughly 10 million protons. Each proton weighs about 2,000 times more than each electron inside that virus. And what our results showed is that the neutrino has a mass less than 1/ 500,000 of a single electron!

Let me put it another way. In each cubic centimeter of space around you, there are about 300 neutrinos zipping through. These are remnants of the early universe, just after the Big Bang. If you added up all the neutrinos residing inside the sun, you’d get about a kilogram or less. So, yeah, it’s small.

Q: What went into determining this new mass limit for the neutrino, and what was MIT’s role in the search?

A: This new mass limit comes from studying the radioactive decay of tritium, an isotope of hydrogen. When tritium decays, it produces a helium-3 ion, an electron, and an antineutrino. We actually never see the antineutrino, however; the electron carries information about the neutrino’s mass. By studying the energy distribution of the electrons ejected at the highest energies allowed, we can deduce the mass of the neutrino, thanks to Einstein’s equation, E=mc2.

However, studying those high-energy electrons is very difficult. For one thing, all the information about the neutrino is embedded in a tiny fraction of the spectrum — less than 1 billionth of decays are of use for this measurement. So, we need a lot of tritium inventory. We also need to measure the energy of those electrons very, very precisely. This is why the KATRIN experiment is so tricky to build. Our very first measurement presented today is the culmination of almost two decades of hard work and planning.

MIT joined the KATRIN experiment when I came to Boston in 2005. Our group helped develop the simulation tools to understand the response of our detector to high precision. More recently, we have been involved in developing tools to analyze the data collected by the experiment.

Q: Why does the mass of a neutrino matter, and what will it take to zero in on its exact mass?

A: The fact that neutrinos have any mass at all was a surprise to many physicists. Our earlier models predicted that the neutrino should have exactly zero mass, an assumption dispelled by the discovery that neutrinos oscillate between different types. That means we do not really understand the mechanism responsible for neutrino masses, and it is likely to be very different than how other particles attain mass. Also, our universe is filled with primordial neutrinos from the Big Bang. Even a tiny mass has a significant impact on the structure and evolution of the universe because they are so aplenty.

This measurement represents just the beginning of KATRIN’s measurement. With just about one month of data, we were able to improve previous experimental limits by a factor of two. Over the next few years, these limits will steadily improve, hopefully resulting in a positive signal (rather than just a limit). There are also a number of other direct neutrino mass experiments on the horizon that are also competing to reach greater sensitivity, and with it, discovery!

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