New JWST Images – James Webb Space Telescope (JWST) astronomers have continued to release new images. Among them is a mosaic covering an area about eight times the size of Webb’s First Deep Field released in July. The mosaic was made for the CEERS program, which is surveying a fraction of one square degree of sky with JWST in various infrared wavelengths. Like the JWST deep field, it is full of galaxies, some of them extremely distant.
Farthest Galaxy (Again) – A galaxy, designated CEERS-93316, was observed by astronomers using the James Webb Space Telescope, setting a new record for the farthest object ever seen. The record it broke was only a few months old. CEERS-93316 is so distant that the light observed left there only 235 million years after the Big Bang. This measurement is preliminary and will have to be confirmed with a spectrum. The redshift of the galaxy was estimated at 16.7, which means that the expansion of the Universe has stretched light from the object so that its wavelength is 17.7 times what it was when emitted. Theoretically Webb should be able to see galaxies whose light left as little as 100 million years after the Big Bang, if galaxies had indeed formed by then. So likely this record will be broken often by new Webb data. In fact, there is a galaxy suspected of having redshift of 20 in some even more recent images.
Black Widow Star – Astronomers at the University of California, Berkeley measured the mass of a recently discovered “black widow” star, a neutron star gravitationally eating material from its close companion star. Only about two dozen such black widow stars are known. If one consumes too much material, it will collapse under its own gravitation and become a black hole. The exact mass at which collapse occurs is not known, so astronomers keep measuring masses of black widow stars to find that mass limit. The new discovery is the most massive yet seen, at about 2.35 times the Sun’s mass, so it becomes the current best estimate of the mass limit before collapse. The newly measured star, known as PSR J0952-0607, has apparently been spun up by the material it has eaten, and is rotating 707 times per second, making it one of the fastest spinning neutron stars known. It is about 20,000 light-years away in the constellation Sextans. It has eaten so much of its companion star that the companion’s mass is down to about 20 times that of Jupiter. Observations of the system with the Keck I telescope in Hawaii established the masses of the component stars.
GRB in Millimeter Light – When a neutron star merges with its binary companion star, it emits a short gamma-ray burst (GRB) which contains more energy than a star gives off in its lifetime even though it lasts only a fraction of a second. In types of light other than gamma rays, the event is followed by a much longer-lasting afterglow, which is caused by jets interacting with surrounding gas. For the first time, such an afterglow has been detected in millimeter light, a form between radio and infrared. Astronomers at Northwestern University using the radiotelescope array ALMA, located in Chile, made the observation. The event occurred when the Universe was 40 percent of its current age, but the light took this long to get here due to the object’s great distance. This event was also detected in radio and X-rays. The ALMA observations pinpointed exactly which galaxy was host to the GRB. The researchers also observed the host galaxy in visible light and infrared. The data gathered allowed astronomers to calculate the angle of the cone shape that the jets occupy. This angle helps astronomers understand the fraction of such events that are observable, the total energy of the events, and the density of material around the events. The energy determined for this event made it one of the most powerful GRBs known.
Gas in a Circumplanetary Disk – Astronomers at the University of Florida recently discovered the third confirmed circumplanetary disk. This disk is likely forming moons around a forming gas giant planet. The circumplanetary disk was found in a gap in the protoplanetary disk circling a star known as AS 209. The first detection of gas in any circumplanetary disk was just made using the ALMA radiotelescope array observing this system. The forming planet is orbiting surprisingly far from its star, more than 200 times the Earth’s distance from the Sun. This star is estimated to be only 1.6 million years old, so planet and moon formation is in its early stages. The star and its forming planetary system are located about 395 light-years away in the constellation Ophiuchus. Webb Telescope observations are planned to confirm the forming planet.
Martian Meteorite Source – Scientists at Curtain University pinpointed which impact crater on Mars launched debris into space, a piece of which fell to Earth in Western Sahara, and became known as the “Black Beauty,” or NWA 7034 meteorite. The researchers conducted a computer search of all the impact craters on Mars, and found only one, named Karratha, matched the meteorite’s characteristics, including the age the meteorite was launched from Mars, the magnetic field strength, the potassium and thorium content, the crater size for the energy to launch debris into space, the age of crater ejecta previously covering the area of Karratha matching the age of other meteorite material, and more. It is hoped that similar techniques may discover the sources of other Martian or lunar meteorites.
Asteroid Fracturing – Scientists at Université Côte d’Azur studying close-up images of asteroid Bennu taken by the OSIRIS-REx spacecraft found that the Sun’s heat, repeatedly applied as the asteroid rotates, causes rocks to fracture in time scales of 10,000 to 100,000 years. Scientists previously estimated such rock fracturing would take millions of years. Images of more than 1,500 rock fractures on Bennu were used in the study. The predominant direction of fractures indicates they were caused by the Sun’s heat. The rotation period of Bennu is 4.3 hours. The daytime surface temperature reaches about 260 degrees Fahrenheit.
Interstellar Object – In 2014, an object estimated to be half a meter wide, crashed in the ocean off the coast of Papua New Guinea. The best tracking estimates of its speed indicate that it likely originated outside the Solar System. Scientists at Harvard University believe that they know the impact point within thirty-six square miles, so efforts are being made to promote an expedition to try to find the object or its fragments on the ocean floor. Because objects from outside the Solar System are so rare, finding this object and studying it would add greatly to our knowledge of conditions in other stellar systems.
Mars Sample Return – NASA completed its system requirements review for returning samples from Mars. The rover Perseverance is now collecting those samples. So far it has sealed up 11 rock/soil samples and one atmospheric sample. NASA had previously planned to send another rover in a few years to gather the samples from Perseverance or wherever Perseverance stored them. Now, the new system requirements have Perseverance itself, aided by two newly-planned Mars helicopters, gather the samples and place them on a soon-to-be-developed Mars Ascent Vehicle, which will launch the samples into Mars orbit. The samples will then be transferred to another rocket that will be parked orbiting Mars, known as the Earth Return Orbiter, using its robotic arm. The latter rocket then returns the samples to Earth by 2033. These spacecraft are to be supplied by NASA and the European Space Agency (ESA).
Danuri – South Korea launched its first lunar spacecraft, named Danuri, which means “enjoy the Moon.” The launch rocket was a SpaceX Falcon 9. It is scheduled to move into lunar orbit mid December. A planned year-long mission will search for landing spots for future missions, map lunar resources, and test space technologies.
SLS To Launch – As Astro Update goes to press, the first Space Launch System (SLS) rocket is on its launch pad in Florida preparing for its Artemis 1 mission. It will orbit the Moon for most of its 42-day flight, then return to Earth. Three test dummies, named Moonikin, Helga and Zohar, are seated in the Orion capsule atop the rocket, but no humans. The next flight of an SLS rocket will be the Artemis 2 mission, which will take humans around the Moon for the first time since 1972. Artemis 3 will land humans near the lunar south pole, now scheduled for 2025. SLS is the largest, most powerful rocket ever built.
Spent Rocket Falls – The first stage of the Long March 5B rocket that launched a module of the Chinese Tiangong space station in July, fell to Earth uncontrolled nearly a week later, somewhere near Borneo. Normally such rocket stages are safely flown under control into an empty area of ocean. Possibly it was intended to do so, but something failed. NASA condemned the lack of control and lack of information as irresponsible. The 5B first stage is about 100 feet long and weighs over 20 tons, so could do considerable damage if it hit something or someone.
Lucy – Soon after NASA’s launch of the Trojan asteroid mission Lucy, mission control commanded the spacecraft to spread its two circular solar panels, but only one latched into the fully spread position. Mission operators investigated and found that on the troubled panel, the lanyard that pulls the panel open had apparently tangled on a spool. After much study, they decided to power on both the panel deployment motor and its backup motor at the same time. This sort of worked. The panel is at least 98 percent opened now, and though not latched, is held so stiffly that it should suffice for the entire mission. Lucy will flyby the first of its nine asteroid targets in 2025 and the last in 2033.
Ten Years on Mars – The Curiosity Mars rover celebrated ten Earth years on the Red Planet in early August. It has driven nearly 18 miles and ascended about 2,050 feet exploring Gale Crater. It has analyzed 41 rock and soil samples. Although a few parts have broken, notably cracks in its wheels, it is operating well enough that NASA authorized three more years of budget to continue roving. Its observations showed that Gale Crater long ago held a lake that persisted for a long time.
Liquid-Mirror Telescope – India completed construction and achieved first light of a four-meter telescope on a mountain in the Himalayas that uses liquid mercury as the primary reflecting surface. The primary mirror is spun at such a speed to shape the liquid into a paraboloidal shape of the correct focal length. It can point only straight up, but it has a wide field produced by a multi-lens corrector system. As the sky drifts across the field of view, the image on the detector is electronically drifted to compensate, allowing long exposures. It is a joint project with Belgium and Canada and is known as the International Liquid Mirror Telescope, or ILMT.