More than four years after its launch, the OSIRIS-REx spacecraft has pulled off what it was designed to do. On October 20, 2020, the space probe descended to the surface of an asteroid, named Bennu, and grabbed a sample of its rubbly terrain. O-REx, as the probe is nicknamed, actually overachieved by apparently collecting perhaps as much as two kilograms—way over the minimum desired sample of 60 grams. The sample container so overfloweth that some bits of Bennu escaped back into space, due to some larger chunks initially blocking the filled-to-the-brim canister from closing. With that issue resolved and the precious material safely stowed, O-REx will now leave Bennu, where the probe has orbited since December 2018. O-REx will next fly by Earth in September 2023, jettisoning a sample return capsule through our world's atmosphere to land in the Utah desert for retrieval. The sample O-REx has captured is pristine asteroidal material from the formation of the solar system 4.6 billion years ago. Labs around the world will queue up for small samples of the overall sample to learn more about the conditions during our solar system's dawn. A chief goal of this work will be to assess how the ingredients on hand at that time eventually led to beings such as ourselves—being curious, and capable enough, to go out and grab those very ingredients, millions of miles away from our planetary home.
The elements left behind reveal probabilities of supernovae pathways
Type Ia supernovae involve remnants of Sunlike stars called white dwarfs. To blow up as a thermonuclear explosion, a white dwarf must either merge with another white dwarf or accumulate mass from a normal companion star, eventually triggering a runaway fusion reaction. Astronomer have remained unsure of how common these two pathways are in comparison to each other, though. A new study from researchers at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) at the University of Tokyo has reexamined the explosions from white dwarfs to account for how the element manganese is produced, finding that the companion star path makes ample manganese. The team then looked at manganese abundances in the local Milky Way and found that at least three-quarters of the Type Ia supernovae in our vicinity must have been of the companion-star-variety. The results help solidify our understanding of supernovae progenitor stars and how they tie in with galactic elemental abundances.
An exoplanet's mass and brightness both known for the first time
In a first, astronomers have obtained a direct image of a planet for which there had previously only been an indirect detection via the so-called radial velocity technique. That technique relies on observing "wobbles" in a star's light as it and a hosted planet gravitationally tug on each other. The technique yield's a planet's mass. Direct imaging instead reveals a planet's brightness by directly catching light in a telescope that is coming from the planet. A researcher at the Kavli Institute for Cosmology, Cambridge (KICC) led a research effort to doubly detect the exoplanet, called beta Pictoris c. Having mass and brightness information for more planets will further advance exoplanetary science, particularly by better constraining planetary formation models.
They grow up so fast: Young galaxies look surprisingly mature
Research at KICC and KIPMU revealed in a study this past month that around a fifth of galaxies in the universe's early epochs contained high levels of dust and heavy elements—products of previous star birth and death. In this era, about one billion to 1.5 billion years post-Big Bang, nearly all galaxies in the sample observed were contrarily expected to be youthfully dust-free. Just as surprisingly, a goodly number of the galaxies had already developed disk-like shapes, a common feature of galaxies that have had time to evolve. Further research will try to tease out if unusual aspects of the precocious galaxies' cosmic environments played a role in accelerating their development.
In a profile story about Nicholas Demos, a graduate student at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research, we learn about how he designs and tests exquisitely sensitive mirrors. These mirrors serve a special role in the profound scientific exercise of detecting gravitational waves—ripples in the spacetime fabric of the universe itself. Although generated in bulk by cataclysmic events involving massive black holes, when the waves reach Earth, they are tiny and weak, just barely perturbing matter at the scale of a ten-thousandth of the diameter of a proton. The mirrors Demos works on are at the heart of LIGO, the Laser Interferometer Gravitational-wave Observatory, where lasers bounce off of the mirrors within 4 kilometer- (2.5 mile-) long arms. The gravitational waves throw off the lasers' alignment ever so slightly, a perturbation that would be undetectable if the mirrors were not so finely engineered. Demos is continuing work on lowering the miniscule, yet detectable thermal noise in the mirrors, caused by the inevitable movement of atoms in temperatures above absolute zero.
Gamma-ray bursts, or GRBs, rank among the most powerful electromagnetic events in the universe. These extremely luminous phenomena can accordingly be glimpsed at extreme distances. Researchers at the Kavli Institute for Particles Astrophysics and Cosmology (KIPAC) at Stanford University are exploring how GRBs could thus be used as so-called standard candles. Standard candles serve as a means of accurately measuring cosmic distances based on some uniform luminous properties of astrophysical phenomena, which then attenuate based on the inherent distance of the phenomena. A kind of supernova, or stellar explosion, has long stood as the farthest-flung object that could be used as a standard candle, out to about 11 billion light years. But GRBs could extend this type of measurement out to 13.2 billion light years. GRBs are tricky, though, given their wide variance in behavior, origins, and environments. Yet successfully getting a handle on GRBs would equip cosmologists with a powerful new too for measuring our universe.