JWST Survives Micrometeoroid – NASA’s James Webb Space Telescope (JWST) team revealed that a micrometeoroid hit one segment of its primary mirror, causing a very slight degradation in its image. The impacting object was roughly the size of a dust particle, but still a bit larger than pre-launch estimates predicted should hit the mirror during the lifetime of the telescope. The quality of the image still exceeds the original design requirements. The impactor was not a part of any meteor shower.
Neptune Blues Explained – Uranus and Neptune have similar atmospheric compositions but are not the same color. Uranus is somewhat greenish while Neptune has a more bluish hue. Now, researchers at Oxford University have explained the difference using ultraviolet, visible and near-infrared light. Both planets have three layers of haze in their atmospheres. In the middle layer of Uranus, methane ice condenses on the haze particles, which tends to give it a greenish color. Neptune has a faster moving atmosphere, which dissipates the methane ice, keeping the bluer color. The methane gas in both planets’ atmospheres gives the blue color when viewed in sunlight.
Martian Dust – Mars rover Perseverance observed some of the most intense dust activity since landing, including about four daily whirlwinds and occasional gusts lifting huge dust clouds. Jezero Crater, where Perseverance is exploring, might be a major source of atmospheric dust. Meanwhile the solar panels on Insight, the lander about 2,000 miles away from Perseverance, are being obscured by dust, without any whirlwinds to blow the dust off. Ironically, Perseverance is nuclear powered and has no solar panels that would profit from all the whirlwinds it is getting. Instead, the dust has damaged wires on Perseverance’s weather instruments. Spacecraft controllers are attempting to develop new weather software that doesn’t use the damaged wires.
Ingenuity – During tests of the Mars helicopter Ingenuity, NASA controllers found that its inclinometer stopped functioning. This is used just before taking off to determine which way is straight up compared to the tilt of the ground it is sitting on. However, controllers believe that this tilt can be calculated from Ingenuity’s accelerometers, so new software is being sent to the helicopter that doesn’t use the inclinometer.
Asteroid Amino Acids – Scientists at the Japan Aerospace Exploration Agency examining sand and dust samples brought back from asteroid Ryugu by spacecraft Hayabusa2 showed that it contains more than 20 amino acids, the chemical building blocks of life. This supports the theory that some of these amino acids were created in space then brought to the early Earth by asteroid impacts.
Brown Dwarfs Found – Only about 40 brown dwarfs orbiting stars have been directly imaged because of the difficulty to image such a dim object so close to a far brighter star. Brown dwarfs are stars with so little mass that they cannot sustain the hydrogen fusion that powers ordinary stars. A new search method developed by astronomers at the University of Bern has imaged four more brown dwarfs. Their approach is to look only at stars that show some evidence of an orbiting body, such as gravitationally induced wobble. This is similar to the radial velocity method of finding exoplanets. The team selected 25 stars that seemed to indicate some kind of influence and were able to image the four new brown dwarfs.
Variable Stars Found – Over the centuries, astronomers have found 46,000 stars in our Milky Way that vary in brightness, and a smaller number of them outside our galaxy. Astronomers at Ohio State Universe working with the All-Sky Automated Survey for Supernovae, discovered 116,000 more variable stars by bringing together a team of citizen scientists, a computer program taught to recognize variable stars, data from the Gaia spacecraft combined with two infrared surveys, and a network of ground-based telescopes performing follow-up observations.
3D Nebula Maps – The Gaia spacecraft has observed more than a billion stars, measuring their distances from Earth and other properties. Using the Gaia data, astronomers found that when starlight shines through a gaseous nebula, they can calculate the distance to the nebula as well. Astronomers at the Max Planck Institute and Chalmers University applied this technique to make 3D maps of the Orion A and California nebulas. The Orion Nebula M42 is a part of Orion A. They found that Orion A is denser and more complex in structure than the California. The latter was found to have a rather flat structure. Differences in density probably explain why Orion A vastly exceeds the California in star formation. The astronomers plan to use the same methods to make 3D maps of nebulas throughout the Milky Way.
Exoplanets in Gaia Data – An international team of scientists trained a computer program to search the Gaia data for exoplanets, and found two so far. Both are hot Jupiters, gas giants that orbit close to their stars. The planets were confirmed with data from TESS, a planet-finding space telescope. This search has also turned up 41 more suspected planets, which still need confirmation.
Nearby Rocky Exoplanets – Astronomers at the Institute of Astrophysics of Andalusia and the University of Chicago used the TESS planet-finding space telescope to discover a pair of rocky planets orbiting the red dwarf star HD260655, only 33 light-years away. They are 1.2 and 1.5 times the diameter of Earth. The planets were confirmed using the radial velocity technique, yielding their masses and showing they are rocky planets. They are prime candidates to have their atmospheres analyzed by the James Webb Space Telescope, because of their proximity to Earth. They are not candidates on which to look for life, however, because they orbit so close to their star that the surface temperatures are likely several hundred degrees.
Dwarf Galaxy Black Holes – The radiation signature from material falling into the black hole at the center of a dwarf galaxy is easily confused with the radiation from high star formation. As a result, while astronomers are quite sure that supermassive black holes exist at the centers of nearly every full-size galaxy, they are uncertain whether this holds for dwarf galaxies. A team of scientists at the University of North Carolina at Chapel Hill compared computer simulations of star-forming dwarf galaxies with central black holes to radio and ultraviolet observations of a large number of dwarf galaxies, and concluded that central black holes are common in dwarf galaxies as well.
Isolated Black Hole – Theoretically, massive dying stars over the life of the universe should have left 100 million black holes across the Milky Way. However, only a few dozen black holes are known within the Milky Way as only those with observable X-rays created by material falling in from close companion stars are likely to be discovered. Now, astronomers at the Space Telescope Science Institute discovered a black hole about 5,000 light-years away, isolated from any close companion and without material falling in. They found it with microlensing, where a foreground massive object passes in front of a more distant star and gravitationally lenses and magnifies it. About 30,000 microlensing events have been seen by surveys watching for them, and one such event was caused by an object so massive that it likely is a black hole. A second team at the University of California, Berkeley also analyzed the event, but was not as sure of the mass, and claimed it might be a neutron star rather than a black hole, though no other evidence of a neutron star there has been found.
Young Bright Pulsar – Astronomers at Caltech using the Jansky Very Large Array radiotelescope found an object that appeared somewhere between images taken in 1998 and 2018. The observations best fit the characteristics of a rotating neutron star known as a pulsar. It could be the youngest pulsar known. A pulsar is born when a star in a certain mass range explodes as a supernova. Typically the pulsar is not seen for years after it has formed, only after much of the supernova’s ejected debris dissipates. So the date of this pulsar birth cannot be well determined. The newly seen object has been dubbed VT 1137-0337, and lies in a dwarf galaxy 395 million light-years away. The radio signal is similar to that of the famous Crab Nebula pulsar, but is about 10,000 times as intrinsically bright.
Slowly Rotating Neutron Star – An international team of scientists led by astronomers at the University of Manchester discovered a neutron star rotating extremely slowly, taking 76 seconds for each turn. It was seen by the MeerKAT radiotelescope in South Africa. The radio signal is seen for only 0.5 percent of the rotation period, so any similar objects would be difficult to detect. Substructure within the radio pulse suggests it is a pulsar, but polarization of the pulses suggests it is a magnetar, both being types of neutron stars. Astronomers have theorized there should be long period magnetars, and this may be the first found. White dwarf stars have such long rotation periods, but observations of the new discovery at wavelengths other than radio do not look like a white dwarf.
Unusual Nova – The fastest nova ever seen was discovered by an amateur astronomer Seidji Ueda and observed extensively by professional astronomers at Arizona State University. Distinct from a supernova, a nova occurs when hydrogen is gravitationally pulled from a close companion star and then accreted onto a white dwarf star. At a certain point the hydrogen undergoes a nuclear explosion, which astronomers see as a flash of light that typically last weeks or months. This one lasted one day. The Large Binocular Telescope in Arizona is still able to see the dim remnant and continues observations to try to discern why this nova was so quick. The nova is also unusual in that it pulses every 501 seconds, which has continued before, during and after the nova explosion.
Reionization Time Measured – Some time after the Big Bang, the Universe cooled enough for protons and electrons to combine into neutral hydrogen gas. Then, after enough stars formed to light up the neutral hydrogen with ultraviolet light, essentially all hydrogen between galaxies got their electrons stripped off, ionizing them. This event is called the reionization of the Universe. How long reionization took has long been hotly debated. A group of astronomers at the Max Planck Institute for Astronomy measured when ionized hydrogen replaced neutral hydrogen, the end point of reionization, in what they believe is the most precise such measurement thus far. They put the end of reionization at 1.1 billion years after the Big Bang, somewhat later than previous measurements and theory. When reionization occurred can tell scientists what type of stars and galaxies were prevalent, and therefore were the cause of reionization. The new measurement was made by examining the spectral lines imprinted by hydrogen gas clouds on the light from 67 distant quasars that shined through those clouds. The redshift of those lines tells astronomers when the light passed through those clouds. Some of the cosmic web consists of neutral hydrogen, so the astronomers had to disentangle cosmic web spectral lines from those they were measuring.
Growing In Lunar Soil – Researchers at the University of Florida have grown plants in lunar soil for the first time. The plants were thale cress. The researchers planted a few seeds in less than an ounce of lunar soil brought back by three Apollo missions, and provided a nutrient solution, light and water for the plants to grow. The plants adjusted their root structure, more kinked and distorted, to tolerate the different soil.
MAVEN Recovers – Back in February, MAVEN, NASA’s spacecraft studying Mars’ atmosphere, had a problem with both of its Inertial Measurement Units (IMUs). This sent the spacecraft into safe mode, where it stops science operations and awaits commands from Earth. MAVEN controllers developed a navigation method that tracks stars instead of using the IMUs, and so were able to bring MAVEN back into full operation late in May. The spacecraft team had been working on developing star-tracking navigation since the first of the two redundant IMUs had started acting up some time ago. But the team completed installing the new navigation five months ahead of schedule to address the safe mode. Functioning of MAVEN is important not only for its atmospheric science, but also because it is a principal means of relaying data from many of the craft on the surface of Mars back to Earth.
Voyager 1 flew by Jupiter and Saturn in 1979 and 1980 respectively, and has been collecting data on interstellar space for nearly a decade. Recently, it encountered a systems problem that jumbles telemetry data regarding its attitude in space. The problem does not affect the science data that it’s still sending to Earth. Spacecraft controllers are working to troubleshoot the problem and see if it can be fixed with software changes or use of redundant hardware.
