The Perseverance rover has captured its first two slices of Mars.

NASA’s latest Mars rover drilled into a flat rock nicknamed Rochette on September 1 and filled a roughly finger-sized tube with stone. The sample is the first ever destined to be sent back to Earth for further study. On September 7, the rover snagged a second sample from the same rock. Both are now stored in airtight tubes inside the rover’s body.

Getting pairs of samples from every rock it drills is “a little bit of an insurance policy,” says deputy project scientist Katie Stack Morgan of NASA’s Jet Propulsion Lab in Pasadena, Calif. It means the rover can drop identical stores of samples in two different places, boosting chances that a future mission will be able to pick up at least one set.

The successful drilling is a comeback story for Perseverance. The rover’s first attempt to take a bit of Mars ended with the sample crumbling to dust, leaving an empty tube (SN: 8/19/21). Scientists think that rock was too soft to hold up to the drill.
Nevertheless, the rover persevered.

“Even though some of its rocks are not, Mars is hard,” said Lori Glaze, director of NASA’s planetary science division, in a September 10 news briefing.

Rochette is a hard rock that appears to have been less severely eroded by millennia of Martian weather (SN: 7/14/20). (Fun fact: All the rocks Perseverance drills into will get names related to national parks; the region on Mars the rover is now exploring is called Mercantour, so the name Rochette — or “Little Rock” — comes from a village in France near Mercantour National Park.)

Rover measurements of the rock’s texture and chemistry suggests that it’s made of basalt and may have been part of an ancient lava flow. That’s useful because volcanic rocks preserve their ages well, Stack Morgan says. When scientists on Earth get their hands on the sample, they’ll be able to use the concentrations of certain elements and isotopes to figure out exactly how old the rock is — something that’s never been done for a pristine Martian rock.

Rochette also contains salt minerals that probably formed when the rock interacted with water over long time periods. That could suggest groundwater moving through the Martian subsurface, maybe creating habitable environments within the rocks, Stack Morgan says.

“It really feels like this rich treasure trove of information for when we get this sample back,” Stack Morgan says.

Once a future mission brings the rocks back to Earth, scientists can search inside those salts for tiny fluid bubbles that might be trapped there. “That would give us a glimpse of Jezero crater at the time when it was wet and was able to sustain ancient Martian life,” said planetary scientist Yulia Goreva of JPL at the news briefing.

Scientists will have to be patient, though — the earliest any samples will make it back to Earth is 2031. But it’s still a historic milestone, says planetary scientist Meenakshi Wadhwa of Arizona State University in Tempe.

“These represent the beginning of Mars sample return,” said Wadhwa said at the news briefing. “I’ve dreamed of having samples back from Mars to analyze in my lab since I was a graduate student. We’ve talked about Mars sample return for decades. Now it’s starting to actually feel real.”

For the first time, astronomers have captured solid evidence of a rare double cosmic cannibalism — a star swallowing a compact object such as a black hole or neutron star. In turn, that object gobbled the star’s core, causing it to explode and leave behind only a black hole.

The first hints of the gruesome event, described in the Sept. 3 Science, came from the Very Large Array (VLA), a radio telescope consisting of 27 enormous dishes in the New Mexican desert near Socorro. During the observatory’s scans of the night sky in 2017, a burst of radio energy as bright as the brightest exploding star — or supernova — as seen from Earth appeared in a dwarf star–forming galaxy approximately 500 million light-years away.

“We thought, ‘Whoa, this is interesting,’” says Dillon Dong, an astronomer at Caltech.

He and his colleagues made follow-up observations of the galaxy using the VLA and one of the telescopes at the W.M. Keck Observatory in Hawaii, which sees in the same optical light as our eyes. The Keck telescope caught a luminous outflow of material spewing in all directions at 3.2 million kilometers per hour from a central location, suggesting that an energetic explosion had occurred there in the past.
The team then found an extremely bright X-ray source in archival data from the Monitor of All Sky X-ray Image (MAXI) telescope, a Japanese instrument that sits on the International Space Station. This X-ray burst was in the same place as the radio one but had been observed back in 2014.

Piecing the data together, Dong and his colleagues think this is what happened: Long ago, a binary pair of stars were born orbiting each other; one died in a spectacular supernova and became either a neutron star or a black hole. As gravity brought the two objects closer together, the dead star actually entered the outer layers of its larger stellar sibling.

The compact object spiraled inside the still-living star for hundreds of years, eventually making its way down to and then eating its partner’s core. During this time, the larger star shed huge amounts of gas and dust, forming a shell of material around the duo.

In the living star’s center, gravitational forces and complex magnetic interactions from the dead star’s munching launched enormous jets of energy — picked up as an X-ray flash in 2014 — as well as causing the larger star to explode. Debris from the detonation smashed with colossal speed into the surrounding shell of material, generating the optical and radio light.

While theorists have previously envisioned such a scenario, dubbed a merger-triggered core collapse supernova, this appears to represent the first direct observation of this phenomenon, Dong says.

“They’ve done some pretty good detective work using these observations,” says Adam Burrows, an astrophysicist at Princeton University who was not involved in the new study. He says the findings should help constrain the timing of a process called common envelope evolution, in which one star becomes immersed inside another. Such stages in stars’ lives are relatively short-lived in cosmic time and difficult to both observe and simulate. Most of the time, the engulfing partner dies before its core is consumed, leading to two compact objects like white dwarfs, neutron stars or black holes orbiting one another.

The final stages of these systems are exactly what observatories like the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, detect when capturing spacetime’s ripples, Dong says (SN: 8/4/21). Now that astronomers know to look for these multiple lines of evidence, he expects them to find more examples of this strange phenomenon.