Newly-discovered white dwarf is most extreme, has greatest mass: Scientists
In their death throes, roughly 97% of all stars become a smoldering stellar zombie called a white dwarf, one of the densest objects in the cosmos. A newly discovered white dwarf is being hailed as the most “extreme” one of these on record, cramming a frightful amount of mass into a surprisingly small package.
Scientists said on Wednesday this highly magnetized and rapidly rotating white dwarf is 35% more massive than our sun yet boasts a petite diameter only a bit larger than Earth’s moon. That means it has the greatest mass and, counterintuitively, littlest size of any known white dwarf, owing to its tremendous density.
Only two other types of objects – black holes and neutron stars – are more compact than white dwarfs.
The way this white dwarf, named ZTF J1901+1458, was born also is unusual. It apparently is the product of a binary star system in which two stars orbit each other. These two stars separately evolved into white dwarfs at the end of their life cycles, then spiraled toward one another and merged into a single entity.
With even a smidgen more combined mass, this merger would have resulted in an immense stellar explosion called a supernova, said Caltech astrophysicist Ilaria Caiazzo, lead author of the study published in the journal Nature. It still might explode at some point in the future, Caiazzo added.
“This white dwarf is really extreme,” Caiazzo said. “We found an object that is really at the limit of how small and heavy a white dwarf could be.”
It is located relatively nearby in our Milky Way galaxy, about 130 light years from Earth. A light year is the distance light travels in a year – about 5.9 trillion miles (9.5 trillion km).
The white dwarf is actually shrinking very gradually, becoming ever more dense. If it does not explode, that could lead to a core collapse transforming it into a neutron star, another type of stellar remnant about the size of a city, typically formed after certain very massive stars go supernova. This would be a previously unrecognized path to neutron star formation.
The white dwarf was spotted by astrophysicist and study co-author Kevin Burdge from Caltech’s Palomar Observatory.
“White dwarfs are the most common form of stellar remnant,” said Burdge, who worked on the study at Caltech and is headed to MIT. “So it’s stunning to see the most extreme outliers among them.”
Its diameter of roughly 2,670 miles (4,300 km) – approximately the distance from Boston to Los Angeles or London to Tehran – slightly exceeds the moon’s diameter of about 2,160 miles (3,475 km).
While our sun rotates around its axis once every 27 days, this white dwarf does so every seven minutes. Its magnetic field is about a billion times stronger than Earth’s.
Stars with up to eight times the mass of our sun are thought to be destined to end up as a white dwarf. Such stars eventually burn up all of the hydrogen they use as fuel through nuclear fusion. At this point, gravity causes them to collapse and blow off their outer layers in a ‘red giant’ stage, eventually leaving a dense core that is a white dwarf.
White dwarfs initially have high temperatures but gradually cool over time, lacking any new energy source. In roughly 5 billion years, our sun is expected to become a red giant and later a white dwarf.
NASA hands SpaceX contract for first mission to Jupiter's moon Europa – Fox Business
NASA’s (National Aeronautics and Space Administration) Southern California-based Jet Propulsion Laboratory (JPL) has awarded SpaceX (Space Exploration Technologies Corp.) with the launch services contract for the Earth’s first mission to conduct detailed investigations of Europa.
The “Europa Clipper” mission is set for October 2024 and NASA said in a Friday release that the spacecraft will launch on a Falcon Heavy rocket from NASA’s Kennedy Space Center in Florida.
The contract award is approximately $178 million dollars.
The world – discovered first by famed astronomer Galileo Galilei – shows strong evidence for an ocean of salty water beneath the planet’s crust, thought to contain twice as much water as Earth’s oceans combined.
NASA believes that the moon’s ice shell is around 10 to 15 miles thick and its internal ocean is estimated to be around 40 to 100 miles deep.
The mission will send Europa Clipper to orbit around Jupiter to perform close flybys of Europa on an elliptical path. The orbiter’s suite of science instruments will help to measure the ocean’s depth and salinity and the thickness of its icy shell, map surface geology and composition, search for plumes of water vapor that could be emitted from Europa’s crust and subsurface lakes and produce high-resolution images of its surface.
JPL notes that understanding Europa habitability will help astrobiologists to better understand how life developed on Earth approximately 382 million miles away, in addition to efforts to find life beyond the blue marble.
While JPL leads the development of the Europa Clipper mission in partnership with the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, for NASA’s Science Mission Directorate in Washington, NASA’s Kennedy-based Launch Services Program will manage the Europa Clipper launch service.
Additionally, the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, will orchestrate program management of the Europa Clipper mission.
Buck Moon rises over Oshawa harbour – insauga.com
July’s orange- or yellow-tinted full moon – known as a Buck Moon – arrived at 10:36 p.m. Friday night.
It’s called the Buck Moon because the antlers of male deer are in full-growth mode at this time.
Indigenous people of Canada have several other names for the phenomenon, including Berry Moon (Anishinabe), Feather Moulting Moon (Cree), Salmon Moon, (Tlingit) and Raspberry Moon (Algonquin, Ojibwe).
The full moon can be viewed in all its glory until tomorrow night.
Photo: Colin Ryan
NASA clears Boeing Starliner for July 30th test flight to ISS – Yahoo Movies Canada
More than 18 months after its failed first attempt to make it to the International Space Station, Boeing’s Starliner is ready for a second shot. Following a flight readiness review, NASA is moving forward with the craft’s upcoming July 30th uncrewed orbital flight test. Unless there’s an unforeseen delay, the capsule will launch from the Space Force’s Cape Canaveral Station mounted on an Atlas V rocket at 2:53PM ET. Should NASA postpone the flight, it will again attempt to carry out the test on August 3rd at the earliest.
The purpose of the flight is for NASA to conduct an end-to-end test of Starliner’s capabilities. It wants to know if the capsule can handle every aspect of a trip to the ISS, including launch, docking as well as atmospheric re-entry. “[Orbital Flight Test-2] will provide valuable data that will help NASA certify Boeing’s crew transportation system to carry astronauts to and from the space station,” the agency said.
If the flight is a success, NASA will move forward with a crewed test of the Starliner. Steve Stich, commercial crew program manager at NASA, said that could happen “as soon as later this year.” Both Boeing and NASA have a lot invested in the viability of Starliner. For the aerospace company, its decision not to conduct an end-to-end test of the craft before its failed 2019 flight left the agency “surprised,” leading to questions about the project. Meanwhile, NASA is keen to have two capsules that can ferry its astronauts to the ISS. Right now, it’s limited to just SpaceX’s Crew Dragon. “It’s very important for the commercial crew program to have two space transportation systems,” Stich told reporters.
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