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A Second Planet May Have been Found Orbiting Proxima Centauri! And it's a Super Earth. – Universe Today

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Astronomers have discovered another candidate exoplanet orbiting our neighbor, Proxima Centauri. A paper announcing these results was just published in the journal Science Advances. If confirmed, it will be the second exoplanet orbiting the star.

It was big news in 2016 when astronomers discovered a planet orbiting Proxima Centauri (PC,) the nearest star to our Sun. That planet, named Proxima b, is potentially habitable, and at the time there was speculation that we could send a robotic explorer there in only a few decades. The discovery of a second planet, even though it’s likely too far away from its star for liquid water, is intensifying interest in the PC system.

The discoverers of this new planet, Proxima c, say that follow-up observations are needed to confirm it as a planet. Changes in the stellar activity of Proxima Centauri indicated the presence of another planet. But they also say that the data they have can’t be explained in terms of any stellar activity itself. Due to its proximity, and also its angular separation from the star, it is a prime candidate for follow-up observations—and even imaging—with next generation telescopes.

Proxima c’s mass is about half that of Neptune and its orbit is about 1.5 times that of Earth. Its temperature is about -200 C, if it has no atmosphere. Proxima Centauri has undergone intense astronomical scrutiny in the last few years, and that has ruled out the presence of any Jupiter-sized planets between 0.8 and 5+ astronomical units from the star. But finding Proxima c is still surprising, because its presence challenges our models of how super-Earths form and evolve.

The lead author of this study is Mario Damasso from the INAF Astrophysical Observatory of Turin, Italy. The study is titled “A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU.” It was published on January 15th, 2020.

Hugh Jones, a Professor of Astrophysics at Hertfordshire University, was also involved in the study. In an article in “The Conversation,” Jones pointed out how difficult it can be to separate data showing the presence of a planet, from data showing stellar activity at the host star. “Just like our sun, Proxima has spots caused by regions of intense magnetic activity which are moving in and out of view, changing in intensity on a variety of timescales. These features need to be considered when searching for any planetary signals.”

Like our Sun <above>, Proxima Centauri has sunspots that can confound astronomers searching for exoplanets. Sunspots are dark areas on the surface of the Sun that are cooler than the surrounding areas. They form where magnetic fields are particularly strong. Image: NASA/SDO/AIA/HMI/Goddard Space Flight Center

Even though stellar activity doesn’t match the data, the discoverers are being cautious until follow-up observations can either confirm or deny the presence of Proxima c, and definitively rule out stellar activity.

The discovery of this new candidate exoplanet is contained in this new paper, but the history goes back a few years.

Multiple teams of scientists have scoured Proxima Centauri for exoplanets. Much of their work depended on radial velocity data, notably from the ESO’s HARPS (High Accuracy Radial velocity Planet Searcher.) Study by study, astronomers have excluded the presence of certain mass-range planets within certain AU ranges from PC.

A 1999 study excluded the presence of any planets beyond 1700 AUs of PC, because PC itself orbits Alpha Centauri AB. A 2019 study set an upper limit of 0.3 Jupiter masses for any planet within 10 AU of PC. That same study excluded the presence of planets between 10 and 50 AU in the mass range 0.3 to 8 masses of Jupiter. Other studies put on more constraints.

But astronomers also know that red dwarfs host more small planets than other types of stars. So they kept looking.

Red dwarfs host more small planets than other types of stars. This is an artist’s impression of the TRAPPIST-1 system, showcasing all seven planets in various phases. Image Credit:  NASA/JPL-Caltech
Red dwarfs host more small planets than other types of stars. This is an artist’s impression of the TRAPPIST-1 system, showcasing all seven planets in various phases. Image Credit: NASA/JPL-Caltech

Can We Really Send A Spacecraft There?

The Breakthrough Starshot Initiative (BSI) thinks they can send a tiny spacecraft to Proxima Centauri.

When the Centauri b exoplanet was discovered in 2016, the BSI got to work. They think they can send a nano-spacecraft with cameras to within one AU of the planet and return images much more detailed than we can hope to achieve with any telescope. They say they should be able to return images showing continents and oceans. On their website, BSI says “To achieve comparable resolution with a space telescope in Earth’s orbit, the telescope would have to be 300km in diameter.”

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But even though PC is “close” in astronomical terms, it’s still an immense distance away. At 4.2 light years away, it would still take decades to get there, travelling at 20% the speed of light (about 216,000,000 kilometers per hour.) Currently, the fastest spacecraft is NASA’s Parker Solar Probe, which will reach a top speed of only 692,000 km/h.

But whether we can get a spacecraft there or not is only part of the story. Due to its proximity, the Proxima Centauri system is an observable laboratory for understanding other solar systems. And its presence and proximity might spur further technological development needed to study it and other systems in more detail.

As Hugh Jones said in his article at The Conversation, “Ultimately, the discovery of multiple signals from the very closest star shows that planets are more common than stars. Proxima represents an excellent location for understanding the closest exoplanets and developing new technologies to better understand the universe we live in.”

Proxima c’s existence is problematic, or at least significant, for our planet formation models. Among super-Earth planets around low-mass stars detected by radial velocity, Proxima c would have both the longest period and the lowest mass. It would also be the furthest distance from its parent star than the frost line in the original protoplanetary disk. The frost line was probably at 0.15 AU.

The authors say that it’s unlikely that Proxima c was kicked out from its initial position closer to the star due to some instability, “because its orbit is consistent with a circular one and because of the absence of more massive planets on shorter orbital distance.”

In their paper, they say, “The formation of a super-Earth well beyond the snowline challenges formation models according to which the snowline is a sweet spot for the accretion of super-Earths, due to the accumulation of icy solids at that location.”

Proxima Centauri is a red dwarf star, or M dwarf. It’s about 4.2 light years away from the Sun, making it our closest neighbour. It’s the third star in a trinary system, with the Alpha Centauri AB binary star. Proxima Centauri is about 13,000 AU from Alpha Centauri AB, and was discovered in 1915.

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New species of crested dinosaur identified in Mexico

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A team of palaeontologists in Mexico have identified a new species of dinosaur after finding its 72 million-year-old fossilized remains almost a decade ago, Mexico’s National Institute of Anthropology and History (INAH) said on Thursday.

The new species, named Tlatolophus galorum, was identified as a crested dinosaur after 80% of its skull was recovered, allowing experts to compare it to other dinosaurs of that type, INAH said.

The investigation, which also included specialists from the National Autonomous University of Mexico, began in 2013 with the discovery of an articulated tail in the north-central Mexican state of Coahuila, where other discoveries have been made.

“Once we recovered the tail, we continued digging below where it was located. The surprise was that we began to find bones such as the femur, the scapula and other elements,” said Alejandro Ramírez, a scientist involved in the discovery.

Later, the scientists were able to collect, clean and analyze other bone fragments from the front part of the dinosaur’s body.

The palaeontologists had in their possession the crest of the dinosaur, which was 1.32 meters long, as well as other parts of the skull: lower and upper jaws, palate and even a part known as the neurocranium, where the brain was housed, INAH said.

The Mexican anthropology body also explained the meaning of the name – Tlatolophus galorum – for the new species of dinosaur.

Tlatolophus is a mixture of two words, putting together a term from the indigenous Mexican language of Nahuatl that means “word” with the Greek term meaning “crest”. Galorum refers to the people linked to the research, INAH said.

 

(Reporting by Abraham Gonzalez; Writing by Drazen Jorgic; Editing by Ana Nicolaci da Costa)

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Alberta family searches for answers in teen's sudden death after COVID exposure, negative tests – CBC.ca

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A southern Alberta mother and father are grappling with the sudden, unexplained death of their 17-year-old daughter, and with few answers, they’re left wondering if she could be the province’s youngest victim of COVID-19.

Sarah Strate — a healthy, active Grade 12 student at Magrath High School who loved singing, dancing and being outdoors — died on Monday, less than a week after being notified she’d been exposed to COVID-19.

While two tests came back negative, her parents say other signs point to the coronavirus, and they’re waiting for more answers. 

“It was so fast. It’s all still such a shock,” said Sarah’s mother, Kristine Strate. “She never even coughed. She had a sore throat and her ears were sore for a while, and [she had] swollen neck glands.”

Kristine said Sarah developed mild symptoms shortly after her older sister — who later tested positive for COVID-19 —  visited from Lethbridge, one of Alberta’s current hot spots for the virus.

The family went into isolation at their home in Magrath on Tuesday, April 20. They were swabbed the next day and the results were negative.

‘Everything went south, super-fast’

By Friday night, Sarah had developed fever and chills. On Saturday, she started vomiting and Kristine, a public health nurse, tried to keep her hydrated.

“She woke up feeling a bit more off on Monday morning,” Kristine said. “And everything went south, super-fast.”

Sarah had grown very weak and her parents decided to call 911 when she appeared to become delirious.

“She had her blanket on and I was talking to her and, in an instant, she was unresponsive,” said Kristine, who immediately started performing CPR on her daughter.

When paramedics arrived 20 minutes later, they were able to restore a heartbeat and rushed Sarah to hospital in Lethbridge, where she died.

“I thought there was hope once we got her heart rate back. I really did,” recalled Sarah’s father, Ron.

“He was praying for a miracle, and sometimes miracles don’t come,” said Kristine.

Strate’s parents say her health deteriorated quickly after being exposed to COVID-19. She died at Chinook Regional Hospital in Lethbridge on Monday. (Ron Strate)

Searching for answers

At the hospital, the family was told Sarah’s lungs were severely infected and that she may have ended up with blood clots in both her heart and lungs, a condition that can be a complication of COVID-19.

But a second test at the hospital came back negative for COVID-19.

“There really is no other answer,” Ron said. “When a healthy 17-year-old girl, who was sitting up in her bed and was able to talk, and within 10 minutes is unconscious on our floor — there was no reason [for it].”

The province currently has no record of any Albertans under the age of 20 who have died of COVID-19.

According to the Strate family, the medical examiner is running additional blood and tissue tests, in an effort to uncover the cause of Sarah’s death.

‘Unusual but not impossible’

University of Alberta infectious disease specialist Dr. Lynora Saxinger, who was not involved in Sarah’s treatment, says it is conceivable that further testing could uncover evidence of a COVID-19 infection, despite two negative test results.

However, she hasn’t seen a similar case in Alberta.

“It would be unusual but not impossible because no test is perfect. We have had cases where an initial test is negative and then if you keep on thinking it’s COVID and you re-test, you then can find COVID,” she said.

According to Saxinger, the rate of false negatives is believed to be very low. But it can happen if there are problems with the testing or specimen collection.

She says people are more likely to test positive after symptoms develop. 

“The best sensitivity of the test is around day four or five of having symptoms,” she said. “So you can miss things if you test very, very early. And with new development of symptoms, it’s always a good time to re-test because then the likelihood of getting a positive test is a little higher. But again, no test is perfect.” 

Sarah deteriorated so quickly — dying five days after she first developed symptoms — she didn’t live long enough to make it to her follow-up COVID-19 test. Instead, it was done at the hospital.

‘An amazing kid’

The Strate family now faces an agonizing wait for answers — one that will likely take months — about what caused Sarah’s death.

But Ron, who teaches at the school where Sarah attended Grade 12, wants his daughter to be remembered for the life she lived, not her death.

Strate, pictured here at three years old, had plans to become a massage therapist. She attended Grade 12 at Magrath High School and was an active, healthy teenager who was involved in sports, music and the school’s suicide prevention group. (Ron Strate)

Sarah was one of five children. Ron says she was strong, active and vibrant and had plans to become a massage therapist after graduating from high school.

She played several sports and loved to sing and dance as part of a show choir. She was a leader in the school’s suicide prevention group and would stand up for other students who were facing bullying.

“She’s one of the leaders in our Hope Squad … which goes out and helps kids to not be scared,” he father said.

“She’s an amazing kid.”

Sarah would often spend hours helping struggling classmates, and her parents hope her kindness is not forgotten.

“She’d done so many good things. Honestly, I’ve got so many messages from parents saying, ‘You have no idea how much your daughter helped our kid,'” said Ron.

“This 17-year-old girl probably lived more of a life in 17 years than most adults will live in their whole lives. She was so special. I love her so much.”

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China launches key module of space station planned for 2022

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BEIJING (Reuters) -China launched an unmanned module on Thursday containing what will become living quarters for three crew on a permanent space station that it plans to complete by the end of 2022, state media reported.

The module, named “Tianhe”, or “Harmony of the Heavens”, was launched on the Long March 5B, China’s largest carrier rocket, at 11:23 a.m. (0323 GMT) from the Wenchang Space Launch Centre on the southern island of Hainan.

Tianhe is one of three main components of what would be China’s first self-developed space station, rivalling the only other station in service – the International Space Station (ISS).

The ISS is backed by the United States, Russia, Europe, Japan and Canada. China was barred from participating by the United States.

“(Tianhe) is an important pilot project in the building of a powerful nation in both technology and in space,” state media quoted President Xi Jinping as saying in a congratulatory speech.

Tianhe forms the main living quarters for three crew members in the Chinese space station, which will have a life span of at least 10 years.

The Tianhe launch was the first of 11 missions needed to complete the space station, which will orbit Earth at an altitude of 340 to 450 km (211-280 miles).

In the later missions, China will launch the two other core modules, four manned spacecraft and four cargo spacecraft.

Work on the space station programme began a decade ago with the launch of a space lab Tiangong-1 in 2011, and later, Tiangong-2 in 2016.

Both helped China test the programme’s space rendezvous and docking capabilities.

China aims to become a major space power by 2030. It has ramped up its space programme with visits to the moon, the launch of an uncrewed probe to Mars and the construction of its own space station.

In contrast, the fate of the ageing ISS – in orbit for more than two decades – remains uncertain.

The project is set to expire in 2024, barring funding from its partners. Russia said this month that it would quit the project from 2025.

Russia is deepening ties with China in space as tensions with Washington rise.

Moscow has slammed the U.S.-led Artemis moon exploration programme and instead chosen to join Beijing in setting up a lunar research outpost in the coming years.

(Reporting by Ryan Woo and Liangping Gao; Editing by Christian Schmollinger, Simon Cameron-Moore and Lincoln Feast.)

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