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

Earliest Cluster of Galaxies – When the first stars formed in the early Universe, essentially all of space was filled with neutral hydrogen gas. Much of the light emitted by these first stars was in the ultraviolet, but neutral hydrogen absorbs ultraviolet, obscuring observations of them. Over time, strong ultraviolet light from these primordial stars or newly formed quasars, knocked the electrons off of the surrounding hydrogen atoms, ionizing them and allowing the ultraviolet light to transmit through so their light might eventually reach Earth. But it remains difficult to make observations of these first stars. A new observation by astronomers with the Carnegie Institution for Science found the earliest known dense cluster of forming galaxies, a rare sight that will help astronomers understand how these early stars and galaxies of stars coalesced. Spectroscopic observations of the cluster’s redshift found it to be the most distant and therefore earliest known dense cluster of galaxies. The find was made during a search for early galaxies known as the LAGER search. That project found dozens of highly redshifted galaxies dated to about 750 million years after the Big Bang, and the most redshifted of these is the newly announced record holder. The initial find was made using the Dark Energy Camera on the Victor Blanco 4-meter telescope in Chile.

Cygnus X-1 Is Farther – The first generally accepted discovery of a black hole is the object known as Cygnus X-1. It was first seen in 1964 by a rocket-launched X-ray telescope. In this binary system, the black hole glows in X-rays as it consumes material from its blue supergiant companion star. Astronomers have had difficulty getting parallax measurements of Cygnus X-1 in X-rays, so their distance estimates for it have been imprecise. A new parallax measurement by astronomers at Curtin University in Australia was carried out using the Very Long Baseline Array, a network of ten radiotelescopes spread across the United States. The same observations also measured the motions of and distance between the black hole and its blue counterpart. From this, astronomers were able to calculate properties of the pair, including distance and masses. They found the mass of the black hole to be 21 solar masses, about 50 percent larger than previous estimates and its distance to be about 7,000 light-years away, also larger than previously thought.

Supernova Remnant Found – Astronomers at the Max Planck Institute for Extraterrestrial Physics discovered a huge supernova remnant in the first all-sky survey released from the eROSITA X-ray space telescope. The remnant has been confirmed in radio data and it was also found to be barely visible in archived 30-year-old X–ray data. Measuring 4.4 degrees across the sky, it is the largest supernova remnant discovered using X-rays. It is unusual also in being located outside the plane of our galaxy. The team that discovered it are calling the remnant “Hoinga”, the medieval name of a town in Germany. A remnant is made of material thrown out by a supernova blast and typically remains visible for about 100,000 years before fading. The rate at which supernovas happen in our galaxy implies that there should be many more remnants than are known, so the search for remnants continues.

FAST Fast Radio Bursts – Fast Radio Bursts (FRBs) happen frequently, perhaps more than one per second, but are rarely seen because radiotelescopes usually aren’t pointed in the right direction at the right time. FAST, the largest radiotelescope dish on Earth, located in China and operated by the Chinese Academy of Sciences has joined the search, already finding three FRBs. Like most FRBs, these originated in distant galaxies. The cause or causes of FRBs remain heavily debated, so more observations are needed to establish the cause.

Solar Particle Source – A coronal mass ejection, or CME, occurs when the Sun throws out hazardous charged particles at high speed. Exactly where the particles come from and how they are accelerated to their high energies are matters of debate. A new observation by researchers at the University College London and George Mason University using data from the Wind and Hinode spacecraft, showed the particles collecting in the lower parts of the Sun’s corona, trapped by powerful magnetic fields until they are released. They found also that the abundances of silicon and sulfur in CMEs matched that of the hot charged gas known as plasma trapped lower in the corona by magnetic fields.

Trojan Comet – An asteroid, known as 2019 LD2 and discovered a couple of years ago among the Jupiter Trojans, was found on further observation by astronomers at Caltech to be a comet: it has a head and tail, unlike an asteroid. The Trojans are asteroids that share Jupiter’s orbit about the Sun, but are located ahead of or behind the planet, around one of the Lagrange gravitationally stable points. Tracing its path backwards, it appears that it was once an icy body in the Kuiper Belt that, after getting too close to Jupiter, was gravitationally deflected toward one of the planet’s Lagrange points and remained captured there. Projecting forward, in a few years it should encounter Jupiter again and likely be deflected into the inner Solar System. It’s presently too far from the Sun, and therefore too cold, for its water ice to sublimate into vapor, so the comet head and tail are probably carbon monoxide or carbon dioxide, which vaporize at much lower temperatures.

Martian Cloud – A long cloud has been seen near the Martian volcano Arsia Mons at certain times of day and times of year since the Viking spacecraft orbited Mars in the 1970s. A new study by scientists at the University of the Basque Country of this cloud has been made using data from five spacecraft orbiting Mars now and in the past. The Visual Monitoring Camera, or VMC, on the European Mars Express spacecraft was particularly helpful in this study because it has a wide field of view. The VMC was originally incorporated on Express to confirm the successful separation of the Beagle 2 lander, which shared a rocket ride to the red planet with Mars Express. However, while Beagle 2 separated successfully in 2003, it was lost during its attempted landing, and the VMC was turned off. Years later the camera was turned back on for the purpose of taking pretty pictures of Mars for public outreach. Recently, the VMC was reclassified as a science camera for such purposes as the Arsia Mons cloud study. The team found the cloud formed before sunrise, stretched out up to several hundred miles long, detached and drifted, and then dissipated within hours. This happens only in Martian spring and summer. Such clouds form when wind is deflected upward over mountains and cooled, both on Earth and Mars. However, this is the longest and most dynamic such cloud.

Martian Water Lost – Ample evidence shows that liquid water flowed on Mars billions of years ago, apparently forming lakes and seas. Today, the planet is a freezing cold desert. Previous work has shown that the planet’s atmosphere and water were largely lost to space but some of the ancient water remains as ice underground and in the polar caps. However, these works had trouble matching the measured ratio of hydrogen and its heavy isotope deuterium found on Mars now. A new computer simulation by researchers at Caltech which included more ways that water could be lost, found that most likely more Martian water was lost by chemically bonding with rocks to become minerals than was lost to space or other means. Their simulation showed that between 30 and 99 percent of the lost water is likely now locked up in clays, hydrated salts and other minerals. Part of the wide uncertainty in this prediction is because of a number of factors scientists are still unsure about, such the precise rate of water loss to space in the past. The new simulation appears to better match the observed hydrogen to deuterium ratio.

Galaxy Distances – A new paper by researchers at the University of Chicago has validated an alternative method of determining distances to galaxies. Edwin Hubble showed that M31 was a galaxy separate from the Milky Way in the 1920s by calculating its distance using the observed brightness of Cepheid variable stars. The true brightness of a Cepheid can be determined by how long it cycles through its changes in brightness. The newly validated method uses stars in the J-region of the Asymptotic Giant Branch (JAGB) on stellar evolution charts in a similar manner. This specific type of giant star is distinguished by a large amount of carbon in its atmosphere and all seem to have the same true brightness. The validation was done by using the JAGB method to determine the distance to the Wolf–Lundmark–Melotte galaxy, and comparing this to other established methods of measuring such distances. The JAGB method has two advantages: It can be used for farther galaxies, because JAGB stars are brighter than stars used in other methods; JAGB stars occur in all types of galaxies, while Cepheid stars are found only in some. Because the expansion rate of the Universe, known the Hubble Constant, depends directly on distance measurements, use of this JAGB method might help settle the disagreements among various methods of measuring the Hubble Constant.

Cosmic Web – Astronomers have long believed that there exists a cosmic web of gas flows connecting the galaxies of the Universe. Observations in recent years have imaged a few portions of this web illuminated by quasars. A new observation, led by researchers at the University of Lyon using the Very Large Telescope in Chile, has imaged a section of this web illuminated by starlight much weaker than quasar light. The galaxies producing the starlight were not individually visible in the observation.

Taking a Star’s Temperature – A red supergiant star dies when it runs out of fuel and undergoes a Type II supernova explosion. Astronomers would like to understand the details of this process, but the temperatures of red supergiants have been difficult to determine as their complex upper atmospheres cause the measurements of their layers to get mixed up. A new study by scientists at the University of Tokyo found that the ratio of the strengths of two different spectral lines of iron can be used to determine red supergiant temperatures. The newly derived temperatures matched well with calculations of overall brightness, which depends on temperature.

Binary Star Catalog – Kareem El-Badry, a Ph.D. student at the University of California, Berkeley, wrote a computer program to search the data from the Gaia space telescope to find orbiting binary stars. The program checks that both stars of any apparent pair are at the same distance and are moving through space together. A search was made, but limited to stars within about 3,000 light-years of Earth, because distance measurements lose their accuracy beyond this. The result is a catalog of 1.3 million binary pairs. The largest previous binary catalog has only about 200 entries. There are probably still more binaries within that distance because many star pairs would be so close that Gaia would see both as a single image. It is thought that at least half of all Sun-like stars are in binary pairs. One finding from the new catalog is that the stars in any given pair are more likely to be of similar mass than would be true if they formed with random masses, which agrees with previous studies. Among the binaries found, about 17,000 of them include one or two white dwarf stars. This is important as the ages of white dwarf stars can be determined more accurately than most other stars and both stars of a binary pair almost always have the same age. This new catalog will also serve as a source list of 17,000 pairs of stars with known ages.

SLS Tested – The Space Launch System (SLS) rocket, intended to take humans to the Moon in NASA’s Artemis program, passed a major test of its core stage. The rocket segment was strapped to the ground and fired for more than eight minutes, the time that it will need to fire to launch to the Moon. The previous attempt at this test, made in January, shut down after only about a minute. This tested stage will be used for the Artemis 1 mission, a flight to the Moon without crew.

Exoplanet Atmosphere Replaced – In 2015 astronomers discovered an exoplanet orbiting a red dwarf star known as Gliese 1132, 41 light-years away in the constellation Vela. It orbits so closely to its star that its year is only 1.6 Earth days. The proximity to the star’s heat and stellar wind should have blown away the planet’s atmosphere. It was a surprise then when recent observations by astronomers at NASA’s Jet Propulsion Lab, using the Hubble Space Telescope, showed the planet has an atmosphere. The team took a spectrum of the atmosphere and it contains hydrogen, methane, hydrogen cyanide and something akin to smog. These gasses are often found in volcanic emanations, so likely continuous volcanic activity from the planet is constantly replenishing the atmosphere as it gets blown away by the star’s proximity.

Antineutrino Resonance Observed – In 1960 Nobel-Prize-winning physicist Sheldon Glashow predicted that an antineutrino with just the right energy would interact with an electron to produce a particle later named the W^– boson in a process that became known as Glashow resonance. The W^– particle was discovered in 1983, but the resonance process occurred at too high an energy to be produced in any earthly particle accelerator. The IceCube neutrino detector has now caught an instance of this resonance involving an antineutrino that was raised to such high energy by a cosmic process. The “just right energy” is at 6.3 quadrillion electronvolts, or “petaelectronvolts,” making this only the third particle with roughly this high energy seen by IceCube in a decade of operation. The search for more instances of this will continue, though such high energy in a neutrino or antineutrino is extremely rare.