“I want to help the Native community get better representation and show that we can help Native citizens get into aerospace engineering, mathematics, or [other STEM career fields]. And the Cherokee and Choctaw Nations are trying to do the same thing on their reservations. They have amazing education networks, so when I realized what they were doing, I wanted to help them be successful [in their efforts]so that they could inspire other tribes to do the same thing.
“When I was talking with the Principal Chiefs of the Cherokee and Choctaw Nations, they said, ‘We need to start making decisions for our people seven generations from now.’ So, they started looking at emerging technologies, and aviation [with a focus on] advanced air mobility was one of those areas. They said, ‘We want to make sure our youth are enabled and equipped to start fielding some of these areas,’ and that’s how I want to help inspire people too.
“Everyone needs an anchor from their community to motivate and inspire them to move forward. I want to be a motivational anchor for the next generation of minorities. You look at minorities, and we often don’t have as many anchors from our past to make us believe [our big dreams are possible]. Providing that legacy now and saying, ‘Hey, I can be an emotional anchor to somebody in my community or with my background [in] two, three, four generations from now,’ and building something outside of myself – that’s what motivates me. I think that’s how we inspire, by leaving those anchors in our timeline.”
— David Zahn, NASA Research Pilot, Ames Research Center
Image Credit: NASA / Dominic Hart Interviewer: NASA / Tahira Allen
A group of dead stars known as “spider pulsars” are obliterating companion stars within their reach. Data from NASA’s Chandra X-ray Observatory of the globular cluster Omega Centauri is helping astronomers understand how these spider pulsars prey on their stellar companions.
A pulsar is the spinning dense core that remains after a massive star collapses into itself to form a neutron star. Rapidly rotating neutron stars can produce beams of radiation. Like a rotating lighthouse beam, the radiation can be observed as a powerful, pulsing source of radiation, or pulsar. Some pulsars spin around dozens to hundreds of times per second, and these are known as millisecond pulsars.
Spider pulsars are a special class of millisecond pulsars, and get their name for the damage they inflict on small companion stars in orbit around them. Through winds of energetic particles streaming out from the spider pulsars, the outer layers of the pulsar’s companion stars are methodically stripped away.
Astronomers recently discovered 18 millisecond pulsars in Omega Centauri — located about 17,700 light-years from Earth — using the Parkes and MeerKAT radio telescopes. A pair of astronomers from the University of Alberta in Canada then looked at Chandra data of Omega Centauri to see if any of the millisecond pulsars give off X-rays.
They found 11 millisecond pulsars emitting X-rays, and five of those were spider pulsars concentrated near the center of Omega Centauri. The researchers next combined the data of Omega Centauri with Chandra observations of 26 spider pulsars in 12 other globular clusters.
A close-up image of Omega Centauri, in X-ray & optical light, shows the locations of some of the spider pulsars. Spider pulsars are a special class of millisecond pulsars, and get their name for the damage they inflict on small companion stars in orbit around them.
There are two varieties of spider pulsars based on the size of the star being destroyed. “Redback” spider pulsars are damaging companion stars weighing between a tenth and a half the mass of the Sun. Meanwhile, the “black widow” spider pulsars are damaging companion stars with less than 5 percent of the Sun’s mass.
The team found a clear difference between the two classes of spider pulsars, with the redbacks being brighter in X-rays than the black widows, confirming previous work. The team is the first to show a general correlation between X-ray brightness and companion mass for spider pulsars, with pulsars that produce more X-rays being paired with more massive companions. This gives clear evidence that the mass of the companion to spider pulsars influences the X-ray dose the star receives.
The X-rays detected by Chandra are mainly thought to be generated when the winds of particles flowing away from the pulsars collide with winds of matter blowing away from the companion stars and produce shock waves, similar to those produced by supersonic aircraft.
Spider pulsars are typically separated from their companions by only about one to 14 times the distance between the Earth and Moon. This close proximity — cosmically speaking — causes the energetic particles from the pulsars to be particularly damaging to their companion stars.
This finding agrees with theoretical models that scientists have developed. Because more massive stars produce a denser wind of particles, there is a stronger shock — producing brighter X-rays — when their wind collides with the particles from the pulsar. The proximity of the companion stars to their pulsars means the X-rays can cause significant damage to the stars, along with the pulsar’s wind.
Chandra’s sharp X-ray vision is crucial for studying millisecond pulsars in globular clusters because they often contain large numbers of X-ray sources in a small part of the sky, making it difficult to distinguish sources from each other. Several of the millisecond pulsars in Omega Centauri have other, unrelated X-ray sources only a few arc seconds away. (One arc second is the apparent size of a penny seen at a distance of 2.5 miles.)
The paper describing these results will be published in the December issue of the Monthly Notices of the Royal Astronomical Society, and a preprint of the accepted paper is available online. The authors of the paper are Jiaqi (Jake) Zhao and Craig Heinke, both from the University of Alberta in Canada.
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Webb Study Reveals Rocky Planets Can Form in Extreme Environments
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Webb Study Reveals Rocky Planets Can Form in Extreme Environments
An international team of astronomers has used NASA’s James Webb Space Telescope to provide the first observation of water and other molecules in the highly irradiated inner, rocky-planet-forming regions of a disk in one of the most extreme environments in our galaxy. These results suggest that the conditions for terrestrial planet formation can occur in a possible broader range of environments than previously thought.
Image: Protoplanetary Disk (Artist Concept)
This is an artist’s impression of a young star surrounded by a protoplanetary disk in which planets are forming.
ESO/L. Calçada
These are the first results from the eXtreme Ultraviolet Environments (XUE) James Webb Space Telescope program, which focuses on the characterization of planet-forming disks (vast, spinning clouds of gas, dust, and chunks of rock where planets form and evolve) in massive star-forming regions. These regions are likely representative of the environment in which most planetary systems formed. Understanding the impact of environment on planet formation is important for scientists to gain insights into the diversity of the different types of exoplanets.
The XUE program targets a total of 15 disks in three areas of the Lobster Nebula (also known as NGC 6357), a large emission nebula roughly 5,500 light-years away from Earth in the constellation Scorpius. The Lobster Nebula is one of the youngest and closest massive star-formation complexes, and is host to some of the most massive stars in our galaxy. Massive stars are hotter, and therefore emit more ultraviolet (UV) radiation. This can disperse the gas, making the expected disk lifetime as short as a million years. Thanks to Webb, astronomers can now study the effect of UV radiation on the inner rocky-planet forming regions of protoplanetary disks around stars like our Sun.
“Webb is the only telescope with the spatial resolution and sensitivity to study planet-forming disks in massive star-forming regions,” said team lead María Claudia Ramírez-Tannus of the Max Planck Institute for Astronomy in Germany.
Astronomers aim to characterize the physical properties and chemical composition of the rocky-planet-forming regions of disks in the Lobster Nebula using the Medium Resolution Spectrometer on Webb’s Mid-Infrared Instrument (MIRI). This first result focuses on the protoplanetary disk termed XUE 1, which is located in the star cluster Pismis 24.
“Only the MIRI wavelength range and spectral resolution allow us to probe the molecular inventory and physical conditions of the warm gas and dust where rocky planets form,” added team member Arjan Bik of Stockholm University in Sweden.
Image: XUE 1 spectrum detects water
This spectrum shows data from the protoplanetary disk termed XUE 1, which is located in the star cluster Pismis 24. The inner disk around XUE 1 revealed signatures of water (highlighted here in blue), as well as acetylene (C2H2, green), hydrogen cyanide (HCN, brown), and carbon dioxide (CO2, red). As indicated, some of the emission detected was weaker than some of the predicted models, which might imply a small outer disk radius.
NASA, ESA, CSA, M. Ramírez-Tannus (Max Planck Institute for Astronomy), J. Olmsted (STScI)
Due to its location near several massive stars in NGC 6357, scientists expect XUE 1 to have been constantly exposed to high amounts of ultraviolet radiation throughout its life. However, in this extreme environment the team still detected a range of molecules that are the building blocks for rocky planets.
“We find that the inner disk around XUE 1 is remarkably similar to those in nearby star-forming regions,” said team member Rens Waters of Radboud University in the Netherlands. “We’ve detected water and other molecules like carbon monoxide, carbon dioxide, hydrogen cyanide, and acetylene. However, the emission found was weaker than some models predicted. This might imply a small outer disk radius.”
“We were surprised and excited because this is the first time that these molecules have been detected under these extreme conditions,” added Lars Cuijpers of Radboud University. The team also found small, partially crystalline silicate dust at the disk’s surface. This is considered to be the building blocks of rocky planets.
These results are good news for rocky planet formation, as the science team finds that the conditions in the inner disk resemble those found in the well-studied disks located in nearby star-forming regions, where only low-mass stars form. This suggests that rocky planets can form in a much broader range of environments than previously believed.
Image: XUE 1 Spectrum detects CO
This spectrum shows data from the protoplanetary disk termed XUE 1, which is located in the star cluster Pismis 24. It features the observed signatures of carbon monoxide spanning 4.95 to 5.15 microns.
NASA, ESA, CSA, M. Ramírez-Tannus (Max Planck Institute for Astronomy), J. Olmsted (STScI)
The team notes that the remaining observations from the XUE program are crucial to establish the commonality of these conditions.
“XUE 1 shows us that the conditions to form rocky planets are there, so the next step is to check how common that is,” said Ramírez-Tannus. “We will observe other disks in the same region to determine the frequency with which these conditions can be observed.”
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
Deputy for Electrified Aircraft Propulsion Integration Joe Connolly
“The goal is to get as many of the wrong ideas out of the way as early as possible.
“So we’ll come up with some idea, especially on the research side, and sometimes it will seem really brilliant on the napkin or in a conversation with one other person.
“[When I started working on electric aircraft propulsion,] I was not familiar with all of the electrical ins and outs. I thought power would just be available, and I could use it when I wanted it. [Our concepts had] all these little hiccups — how they get integrated in the real system, how the battery systems are going to interplay, and all the extra safety things that we need to consider—they allowed us to figure out things a little bit earlier and [give us] a broader perspective.
“The key thing is that when you’re working on something that’s really hard, I think the whole expectation is that you’re going to fail. So we try to fail as many times as we can early on. So when we’re getting closer to an actual demonstration, we’re pretty confident that at that point, we’ve talked to the right people, everyone’s on board, and we’re going to have a safe, larger test campaign.
“It’s always better to fail earlier on and learn as much as you can.”
— Joe Connolly, Deputy for Electrified Aircraft Propulsion Integration, Glenn Research Center
Image Credit: NASA / Jef Janis Interviewer: NASA / Thalia Patrinos
Discovery Alert: Watch the Synchronized Dance of a 6-Planet System
Discovery Alert: Watch the Synchronized Dance of a 6-Planet System
The discovery: Six planets orbit their central star in a rhythmic beat, a rare case of an “in sync” gravitational lockstep that could offer deep insight into planet formation and evolution.
Key facts: A star smaller and cooler than our Sun hosts a truly strange family of planets: six “sub-Neptunes” – possibly smaller versions of our own Neptune – moving in a cyclic rhythm. This orbital waltz repeats itself so precisely it can be readily set to music.
This animation shows six “sub-Neptune” exoplanets in rhythmic orbits around their star – with a musical tone as each planet passes a line drawn through the system. The line is where the planets cross in front of (transit) their star from Earth’s perspective. In these rhythms, known as “resonance,” the innermost planet makes three orbits for every two of the next planet out. Among the outermost planets, a pattern of four orbits for every three of the next planet out is repeated twice.
Animation credit: Dr. Hugh Osborn, University of Bern
Details: While multi-planet systems are common in our galaxy, those in a tight gravitational formation known as “resonance” are observed by astronomers far less often. In this case, the planet closest to the star makes three orbits for every two of the next planet out – called a 3/2 resonance – a pattern that is repeated among the four closest planets.
Among the outermost planets, a pattern of four orbits for every three of the next planet out (a 4/3 resonance) is repeated twice. And these resonant orbits are rock-solid: The planets likely have been performing this same rhythmic dance since the system formed billions of years ago. Such reliable stability means this system has not suffered the shocks and shakeups scientists might typically expect in the early days of planet formation – smash-ups and collisions, mergers and breakups as planets jockey for position. And that, in turn, could say something important about how this system formed. Its rigid stability was locked in early; the planets’ 3/2 and 4/3 resonances are almost exactly as they were at the time of formation. More precise measurements of these planets’ masses and orbits will be needed to further sharpen the picture of how the system formed.
Fun facts: The discovery of this system is something of a detective story. The first hints of it came from NASA’s TESS (the Transiting Exoplanet Survey Satellite), which tracks the tiny eclipses – the “transits” – that planets make as they cross the faces of their stars. Combining the TESS measurements, made in separate observations two years apart, revealed an assortment of transits for the host star, called HD 110067. But it was difficult to distinguish how many planets they represented, or to pin down their orbits.
Eventually, astronomers singled out the two innermost planets, with orbital periods – “years” – of 9 days for the closest planet, 14 days for the next one out. A third planet, with a year about 20 days long, was identified with the help of data from CHEOPS, The European Space Agency’s CHaracterising ExOPlanets Satellite.
Then the scientists noticed something extraordinary. The three planets’ orbits matched what would be expected if they were locked in a 3/2 resonance. The next steps were all about math and gravity. The science team, led by Rafael Luque of the University of Chicago, worked through a well-known list of resonances that potentially could be found in such systems, trying to match them to the remaining transits that had been picked up by TESS. The only resonance chain that matched up suggested a fourth planet in the system, with an orbit about 31 days long. Two more transits had been seen, but their orbits remained unaccounted for because they were only single observations (more than one transit observation is needed to pin down a planet’s orbit). The scientists again ran through the list of possible orbits if there were two additional, outer planets that fit the expected chain of resonances across the whole system. The best fit they found: a fifth planet with a 41-day orbit, and a sixth just shy of 55.
At this point the science team almost hit a dead end. The slice of the TESS observations that had any chance of confirming the predicted orbits of the two outer planets had been set aside during processing. Excessive light scattered through the observation field by Earth and the Moon seemed to make them unusable. But not so fast. Scientist Joseph Twicken, of the SETI Institute and of the NASA Ames Research Center, took notice of the scattered light problem. He knew that scientist David Rapetti, also of Ames and of the Universities Space Research Association, happened to be working on a new computer code to recover transit data thought to be lost because of scattered light. At Twicken’s suggestion, Rapetti applied his new code to the TESS data. He found two transits for the outer planets – exactly where the science team led by Luque had predicted.
The discoverers: An international team of researchers led by Rafael Luque, of the University of Chicago, published a paper online on the discovery, “A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067,” in the journal Nature on Nov. 29.
Tracing a link between two neighbour planet at regular time interval along their orbits, creates a pattern unique to each couple. The six planets of the HD110067 system create together a mesmerising geometric pattern due to their resonance-chain.
Credit: Thibaut Roger/NCCR PlanetS, CC BY-NC-SA 4.0
