Astronomy and space news summarized by Don Lynn from NASA and other sources

Sampling Mars – After its first, unsuccessful attempt to store a drilled sample of Martian rock and soil, the Mars rover Perseverance made two successful samplings of a flat Martian rock nicknamed “Rochette.” Both are now sealed in titanium tubes for a future mission to collect and return to Earth. The sampling and caching system has over 3,000 moving parts, and so is one of the most complex mechanisms ever launched to deep space. Preliminary analysis onboard the rover shows the samples are volcanic with later exposure to water.

Unusual Comet – A newly discovered comet, dubbed “Comet Leonard” due to its discovery by Greg Leonard at the University of Arizona, is going to pass quite close to Venus in December. The closest distance between their orbital paths is only about 30,000 miles and the planet arrives there only about three days after the comet. It is possible that the planet will pass through a debris trail from Leonard, which will cause a meteor shower. Unfortunately for anyone who would like visit Venus to see this shower, that planet is always cloudy. It is unlikely that any such meteor shower would be bright enough to see from Earth, even though it would be above Venus’s clouds and therefore unobscured from Earth. Comet Leonard will likely never return to the inner Solar System because gravitational perturbations from the planets are calculated to boost its speed slightly beyond escape velocity from the Sun.

Unusual Asteroid – An asteroid dubbed 2021 PH₂₇, discovered by astronomers at the Carnegie Institution for Science, has the shortest known asteroid period to orbit the Sun, at 113 Earth days. Its highly elliptical orbit takes it well inside Mercury’s orbit and just outside Venus’s. It is about two-thirds of a mile across. Asteroids that orbit close to the Sun, particularly small ones, are difficult to find because they are always near the Sun’s glare as seen from Earth. It was found using the Dark Energy Camera on the Victor Blanco Telescope in Chile, in images taken near the Sun at twilight. Because the asteroid approaches the Sun so closely, it experiences the largest known precession of its orbit due to General Relativity of any Solar System object. Its surface temperature reaches about 900 degrees Fahrenheit at its closest approach to the Sun. It is likely that gravitational disturbances from the inner planets will, within a few million years, toss it into the Sun or an inner planet or eject it from the inner Solar System. Likely the object came from the asteroid belt, disturbed from there by gravitational effects, but it is also possibly an extinct comet.

TNOs Discovered – The Dark Energy Camera on the Victor Blanco Telescope in Chile is surveying a large portion of the sky to use gravitational lensing, galaxy clustering, and other means to constrain the effects of dark energy. It finds other stuff in the process. A new analysis by researchers at the University of Pennsylvania of data from this survey has found 461 previously undetected bodies in the Kuiper Belt, known as Trans-Neptunian objects (TNOs). A previous analysis of older Dark Energy Camera data discovered 316 TNOs. The new analysis brings the total number of known TNOs to nearly 4,000. None of the newly found objects fits the characteristics of the hypothesized Planet 9, the TNO proposed to explain gravitational effects upon the orbits of the most distant TNOs, but the survey is not thorough enough to rule out the existence of Planet 9.

Unusual Brown Dwarf – Brown dwarfs are objects with masses somewhere between planets and stars. Though nuclear reactions in their cores may fuse some deuterium or lithium, they cannot fuse ordinary hydrogen as true stars do. After their brief flirtation with fusion ends, they cool off and grow dim forever. Brown dwarf masses range from about 13 to 80 times Jupiter’s mass. Because they’re so dim, fewer than 2,000 of them have been found, even though theoretically there should be numbers of them roughly comparable to numbers of stars. A new discovery by astronomers at Caltech further contributes to explaining why few have been found. The discovery is a brown dwarf found in data from the NEOWISE infrared space telescope. It had been overlooked in previous searches for brown dwarfs because its spectrum was unlike that of previously known brown dwarfs. It likely differs because it appears to have less methane than typical. Astronomers hope that looking for this type of spectrum will lead to the discovery of more brown dwarfs.

Earth’s Core Growth – As the Earth’s core slowly cools down, its solid iron-nickel inner core is slowly growing by about a millimeter per year as the surrounding molten iron crystallizes into a solid along the boundary of the two regions. A new study by seismologists at the University of California, Berkeley found that it is expanding unevenly, growing about 60 percent faster on the side roughly under Indonesia than on the opposite side of the Earth. Gravity has kept the inner core from getting very much out of spherical. Scientists aren’t sure as to why the core growth is uneven. One possibility is that it is being affected by the subduction of tectonic plates going on near Indonesia. The uneven growth may affect the direction of the Earth’s magnetic field because the growth contains much iron.

Triggered Supernova – Astronomers at Caltech found evidence that a supernova explosion that occurred in 2014 was triggered by either a black hole or neutron star merging with its companion ordinary star. The star would have exploded at the end of its life of nuclear fusion, but the merging triggered the explosion much sooner. The evidence came from new and archived observations in radio and X-rays, and using the Keck Telescope in Hawaii. The event occurred in a dwarf galaxy 480 million light-years away. The companion stars started out as a pair of ordinary massive stars in a close orbit about each other. Long ago, the brighter star ran out of nuclear fuel and exploded as a supernova, leaving behind either a black hole or a neutron star. About 300 years ago, the black hole or neutron star began dipping into the ordinary star’s atmosphere, which eventually led to their merging, in 2014. The black hole or neutron star disrupted the fusion of the companion, which then exploded as a supernova. Jets formed during the merging, which produced X-rays. The supernova blast hit previously thrown off material, which gave off bright radio emission. The astronomers were tipped off to look for all this when a new object showed up in a radio survey.

Intermediate Mass Black Hole – When a star gets too close to a black hole, intense tidal forces tear the star apart, and the debris heat up as they fall into the black hole, emitting intense radiation. This is known as a tidal disruption event. A new paper by astronomers at the University of Arizona analyzes the X-rays given off by one such event and determined that the star was consumed by an intermediate mass black hole. An intermediate black hole is more massive than one formed from a collapsing star, but less massive than the so-called supermassive black holes found in the centers of most large galaxies. This covers a huge range of mass, between roughly a thousand to a million times the Sun’s mass. Only a handful of candidates for intermediate mass black holes have been found, and many of these are disputed. The black hole mass determined in the new paper is about 10,000 times the Sun’s mass. The new paper also determined the spin rate of the black hole. It was fast enough to show that the black hole did not reach its present size by consuming material falling from random directions, one popular theory for building intermediate black holes.

White Dwarf Aging – White dwarf stars are born when the nuclear furnace at the core of a star finishes fusing helium to carbon and oxygen but doesn’t have enough mass to force fusion of the carbon into heavier elements. They expel their outer layers leaving a hot core. Up to now, scientists thought that the dwarf stars just cool off and fade forever. However, a new study by astronomers at the Università di Bologna found many white dwarfs that continued to fuse some hydrogen, making exceptions to the generally accepted white dwarf theory. The new study observed globular clusters M3 and M13 in ultraviolet to study the hundreds of white dwarfs in them. About 70 percent of the white dwarfs in M13 showed evidence of fusing hydrogen, but the ones in M3 did not. Astronomers have been using the degree of cooling off of white dwarfs to determine their ages. This new study says that sometimes they do not cool off uniformly because the newly discovered hydrogen fusing is occurring, invalidating the age determination. More work is needed to understand when this hydrogen fusing takes place in white dwarfs.

 Probable Galaxy Spur – A new study by astronomers at Caltech of several nearby star-forming nebulas has found that they appear to form a spur off the Sagittarius Arm of our Milky Way galaxy. They were found to lie along a line forming a 60 degree angle with the direction perpendicular to the galaxy radius, while that arm forms a 12 degree angle. Thus they project outward from that galaxy arm. Data to determine these angles came from the Gaia and Spitzer space telescopes.

Galaxy’s Halo – The Milky Way’s halo consists of rarified gas and a sprinkling of stars and is far larger than the galaxy’s disk. A new analysis by astronomers at Space Telescope Science Institute of the spectra of 25 quasars has given astronomers the best picture yet of our galaxy’s halo gas. That gas slightly alters the quasar spectra as their light passes through the gas on its way to Earth. The spectra were archived from the FUSE ultraviolet space telescope. The analysis detected gas 1,000 times less dense than that seen in previous work. Because the researchers only looked for the spectral lines of neutral hydrogen, only cooler gas was detected. Hotter gas would be ionized, not neutral. Areas of infalling and outflowing gas were found, though more of it was infalling. The astronomers estimated that the net infall amounts to about a half solar mass per year. Such infalling gas supplies the galaxy with new material to build stars and planets.

Gravitational Lensing – Astronomers at the Harvard & Smithsonian Center for Astrophysics found a magnified X-ray image in Chandra X-ray Observatory data resulting from gravitational lensing, the bending of the light by gravity. The X-rays were emitted by material surrounding a pair of black holes that are so distant the light left there only two billion years after the Big Bang. It is possible the two objects are instead one black hole and its jet. More observations may be able to distinguish. The gravitational lensing magnified and brightened the observation, helping the astronomers determine there are two separate sources and helping in even detecting such dim and distant objects.

Space Tourists – On September 15, SpaceX launched a crewed Dragon spacecraft into orbit for a three-day sojourn with four non-professional astronauts on board, a first. The mission is known as Inspiration4. Because the Dragon did not dock with the International Space Station, its docking mechanism was removed and replaced by a cupola window. The tab, believed to be under $200 million, was picked up by billionaire Jared Isaacman, who chose three companions. The plan is to raise millions of dollars for St. Jude Children’s Research Hospital by auctioning space artifacts and other activities. One of the space passengers is a physician’s assistant employed at the hospital, whose life was saved as a child by cancer treatment there.

Webb Telescope – Launch of the James Webb Space Telescope from the European spaceport in French Guiana is scheduled for December 18. Previous concerns about the safety and reliability of the Ariane 5 rockets have been resolved. About four weeks after launch, the telescope will arrive at its operating location at the Sun-Earth L2 Lagrange point, about a million miles from Earth, on the anti-sunward side. After testing and calibration, full operation of the telescope is scheduled to begin within six months of launch. Webb will complement the Hubble Space Telescope because while Hubble observes in visible and ultraviolet light, Webb will far exceed Hubble in sensitivity and resolution for infrared observations. Webb was designed for infrared because the farthest objects visible in the Universe have their light redshifted into the infrared by the expansion of the Universe.

Deep Space Network Upgrade – NASA is upgrading its Deep Space Network, the radio dishes located in California, Spain and Australia that communicate with spacecraft. Some of the dishes do planetary radar and radiotelescope functions also. NASA is adding two dishes, increasing the total from 12 to 14, and expanding the radio frequencies used by the dishes. In addition, the control systems will be able to handle multiple communications at once, laser communications are being added to the radio capability of some antennas, and remote operation is being added so that the day shift of operators, wherever that happens to be around the world at any given time, can run the whole system.

ALMA Upgrade – ALMA, a radiotelescope array in Chile, is being upgraded to add a new range of wavelengths which it can detect. The previous range is from 0.3 to 3.6 mm wavelength, while the capability being added is 6 to 8.5 mm. These longer wavelengths are particularly good at detecting dust particles found in star-forming regions and planet-forming disks, as well as at detecting radiation from the epoch of reionization. That epoch is when the first stars in the Universe appeared and their radiation ionized much of the neutral hydrogen of the Universe.