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

Nobel Prizes – The Nobel Prize committee includes astronomy as part of physics and this year three astronomers split the physics prize. Roger Penrose received half of the award for his mathematical work on the properties, even existence, of black holes. The committee split the other half between Andrea Ghez and Reinhard Genzel, recognizing their work tracking the movement of stars near the center of the Milky Way galaxy. They showed the stars were orbiting an extremely massive and relatively small object that could be nothing other than a supermassive black hole. Ghez and her team used adaptive optics and infrared imaging through the Keck Telescope in Hawaii to do the observations, over a span of about 25 years.

OSIRIS-REx is the spacecraft that has been observing the small, near-Earth asteroid Bennu close up for nearly two years. The primary goal of the mission is to bring back to Earth a sample of the asteroid surface material. On October 20, the spacecraft gently touched its sample grabbing mechanism to the asteroid’s surface and all indications are that the sampling worked as planned. Surface material was blown by a puff of nitrogen into a container designed to hold up to about five pounds of dust and rock. However, anything more than about two ounces is considered successful. Arrival back at Earth is scheduled for September 24, 2023. This is planned to be the largest sample returned from space since the Apollo program. When analyzed on Earth, this material should tell scientists a great deal about conditions when the Solar System, including the asteroids, formed about 4.5 billion years ago.

More From Bennu – The OSIRIS-Rex team recently discovered a series of six boulders up to 14 feet across that are unlike any other boulders on Bennu. These bright rocks stood out against the generally drab surface of Bennu, the dark color caused by a high carbon content. Spectrometer observations of the boulders showed that they are pyroxene-rich and match the composition of material seen on Vesta by the Dawn spacecraft. Certain types of meteorites that have fallen to Earth are known to have been blasted into space by an asteroid colliding with Vesta about two billion years ago. Bennu is thought to be a fragment of a larger parent asteroid that was broken up by collision very roughly a billion years ago. Scientists stated that the most likely way the six boulders ended up on Bennu is that fragments of the Vesta collision eventually landed on the parent body of Bennu, and that the boulders survived the breaking up of that parent asteroid, though the Vesta pieces could have later landed on Bennu rather than earlier on its parent.

Yet More – Another recent discovery by OSIRIS-REx is of rocks on Bennu that likely formed in liquid water soon after the Solar System formed. This is possible only in a much larger body, likely the parent body that later broke up to produce Bennu and a large family of other small asteroid fragments. The rocks formed in water are crystallized calcium carbonate. Bennu is about one third of a mile across and appears to be made of broken rubble that accumulated into a single body by gravity.

Comet Aurora – Archived data taken a few years ago by the Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko and analyzed by the Southwest Research Institute, show ultraviolet aurora activity at the comet. This is the first aurora ever seen at a comet. The aurora is caused when charged particles in the solar wind hit the sparse gas surrounding the comet’s nucleus. That nucleus has no magnetic field and hardly any atmosphere, both of which play parts in auroras at most of the planets in our Solar System. The discovery of the aurora was so unexpected that scientists at first thought the ultraviolet glow seen by Rosetta was from dayglow, a phenomenon caused by light photons hitting gas, as opposed to aurora, where charged particles hit gas.

Binary TNO – New observations by volunteer high-school students coordinated by the Southwest Research Institute have shown that a previously known trans-Neptunian object (TNO) is actually a pair of bodies closely orbiting each other about 200 miles apart. The observations were possible because the TNO happened to pass in front of a star, blocking its light, a process known as occulting. In fact, the star was a double star, so it was a case of a double TNO occulting a double star. Timing the two blockages gave sizes of the two components, and the time between gave the distance apart. The only way to make these observations was through this occultation method as the TNO is located past the orbit of Neptune, too far away for any telescope to resolve their binary nature or component sizes.

Very Hot Exoplanet – Cheops, a European space telescope designed to follow up discoveries of exoplanets, has been making science observations since April, and its first major discovery has just been announced. The team discovered one of the hottest planets known, named WASP-189 b. The heat is due to it orbiting about 20 times closer to its star than Earth orbits to the Sun. Its year is just 2.7 Earth days. Also its star is considerably hotter than our Sun, adding to the infernal climate. Metals such as iron evaporate there. The planet is about 1.6 times the diameter of Jupiter. It is spinning so fast that its equator bulges considerably out of spherical. Its orbit is surprisingly inclined, so that it passes nearly over the poles of its star. Likely gravitational disturbance from other planets or a star forced it into this inclination.

Another Hot Exoplanet – A different team, led by astronomers at the University of Bern and the University of Geneva, studied another very hot exoplanet, named WASP-121 b, located 850 light-years away. It too is very close to its star, taking less than two Earth days to orbit. They were able to get a spectrum of the planet’s atmosphere. They found seven vaporized metals: vanadium, iron, chromium, calcium, sodium, magnesium and nickel. Strangely titanium was not found.

Bright Non-Quasar Discovered – Astronomers at the Instituto de Astrofísica de Canarias announced the discovery of the first galaxy ever seen to be as bright in ultraviolet (UV) light as a quasar but is not a quasar. Quasars are distant, supermassive black holes that are some of the most luminous objects in the Universe. Dubbed BOSS-EUVLG1, after the BOSS sky survey that found it, the galaxy emits extreme UV light. Follow-up observations in radio and visible light showed that the extreme UV is being emitted by the exceptional formation of massive stars, at about 1000 times the rate of star formation in our Milky Way galaxy. The researchers found the galaxy to be surprisingly free of dust that would block the UV light from our view. The content of elements heavier than helium was also found to be very low, consistent with the low dust content, since few previous generations of stars would produce both little dust and little heavy elements. This was unexpected because most galaxies with high star formation rates are quite dusty, resulting in their being bright in infrared, not UV. Astronomers predicted that the dust-free stage could last only a cosmically short time, and that is why most high star-formation galaxies would have left that stage and be dusty. The galaxy is so distant that we are seeing the galaxy as it appeared when the Universe was less than 20 percent of its current age.

Captured Globular Cluster Found – An international team of astronomers have identified a population of stars found near the center of our Milky Way galaxy that differ in properties from other stars in the region. They showed that this population was likely the result of a globular cluster being captured by our galaxy about three to five billion years ago. The differing properties included heavy element content, velocity and orbital inclination. The population was found in a study of about 700 stars in the Milky Way center made with the Very Large Telescope (VLT) in Chile, and conducted in infrared to penetrate the dust blocking visible light from this region. About 7 percent of the stars in the region were found to belong to the newly discovered population. The team determined the stars were from a globular cluster by comparing observations to computer simulations of the various ways a population of stars could be created there.

Deficient Globular – Astronomers, led by researchers at Radboud University in the Netherlands, have found a globular cluster orbiting the nearby Andromeda galaxy that has a record low content of elements heavier than helium. The cluster, known as RBC EXT8, has three times less iron than the previous globular record holder and extremely low amounts of magnesium. This means that the cluster has had extremely few generations of stars form in it, as each generation adds heavier elements formed within stars and supernovas. Star cluster formation theories may have to be adjusted to account for this globular cluster. The team plans to look for other heavy-element-deficient globulars to try to understand how they form.

Mass in the Universe – Research led by scientists at the University of California, Riverside, used new method to calculate the total mass content of the Universe, including dark matter. The result is that 31.5 ± 1.3 percent of the Universe consists of mass. Essentially all the rest, 68.5 percent, must be dark energy. Using sky surveys, the team measured the mass density of galaxy clusters and compared that measurement to the results of computer simulations of the Universe developing. Each simulation was computed using a different total mass content, with the team repeating the process until simulation and observations matched. They had to develop a computer tool that measured galaxy cluster mass by its influence on galaxy motions within clusters. The general technique has been used before, but this new study is believed to be the most precise, because it best agreed with other cosmological studies, including that of the cosmic microwave background anisotropies, baryon acoustic oscillations, supernovas and gravitational lensing.

Early Galaxies Discovered – Six galaxies clustered around a supermassive black hole have been found by an international team of astronomers using Chile’s Very Large Telescope. They are so distant the light left there about 0.9 billion years after the Big Bang. This is the earliest such a grouping of galaxies has been found to exist. They lie in a cosmic web of gas, which apparently supplied sufficient gas to form galaxies full of stars and a supermassive black hole so soon in the life of the Universe. The web is seen to extend about 30 million light-years. The black hole has about a billion solar masses. The galaxies are near the limit of what can be seen with current telescopes, so there are probably more galaxies somewhat dimmer in the vicinity that have escaped detection.

Martian Lakes – Two years ago, astronomers working on the ESA’s Mars Express MARSIS instrument, reported finding radar data evidence for a lake of liquid salty water under Mars’ south polar ice cap. Further research using new techniques and more radar data has now found several smaller lakes or ponds nearby. The new techniques were first developed and successfully used to find lakes under glaciers here on Earth.

New Sky Catalog – Pan-STARRS1 is a wide-field 70-inch telescope in Hawaii that has been for about a decade imaging the entire currently visible night sky every week or so in five colors. The goal is to find everything that moves or changes brightness. The Pan-STARRS team, based at the University of Hawaiʻi at Mānoa, also stacks all the images and occasionally releases the most detailed maps of everything in the sky that does not move. The latest such release includes three quarters of the entire sky (the remaining quarter is too far south to image) and includes a classification for every object and a distance for every galaxy. These were calculated by a computer program that has been found to be 96 to 98 percent accurate in classification, and to provide galaxy distances accurate to 3 percent. It contains about three billion stars, galaxies and quasars. This is the largest catalog of the sky made to date.

Spaghettification – Strength of a gravitational tidal force depends on the mass of an object and one’s proximity to it. If one gets close to a black hole, the severe tidal force pulls apart their near side from their far side. This rips apart planets, stars or anyone foolish enough to closely approach a black hole. Those that do approach too close get stretched into strings, and the process is called “spaghettification,” or more formally, tidal disruption event (TDE). Astronomers at the University of Birmingham happened on such an occurrence last year in a galaxy 215 million light-years away, when a star got too close to the galaxy’s supermassive black hole. Astronomers watched the event proceed in a range of wavelengths, from radio to X-rays. Surprisingly the black hole developed jets and threw some star material outward at about 6000 miles per second, while devouring the rest. It was the closest TDE yet observed, and astronomers learned a great deal about such events.

Exoplanet Imaged – Astronomers at the Max Planck Institute for Astronomy have taken the first direct image of an exoplanet that was discovered using the radial-velocity method. The planet is Beta Pictoris c. The image was made using adaptive optics and interferometry on Chile’s Very Large Telescope. Its neighboring planet Beta Pictoris b was directly imaged in 2008. Only about two dozen exoplanets have been directly imaged.