First massive binary star with magnetic fields found
Toronto: Scientists have discovered the first massive binary star, epsilon Lupi, in which both stars have magnetic fields.
A binary star is a star system consisting of two or more stars, orbiting around their common centre of mass.
For the past few years, the BinaMIcS (Binarity and Magnetic Interactions in various classes of Stars) collaboration, formed to study the magnetic properties of close binaries, has been trying to find such an object. They have now discovered one using the Canada-France-Hawaii Telescope.
“The origin of magnetism amongst massive stars is something of a mystery and this discovery may help to shed some light on the question of why these stars have magnetic fields,” said Matt Shultz, a PhD candidate at the Queen’s University in Canada.
In cool stars, such as the Sun, magnetic fields are generated by a convection in the outer portion of the star. However, there is no convection in the outer layers of massive star, so there is no support for a magnetic dynamo.
Nevertheless, approximately 10 per cent of massive stars have strong magnetic fields. Two explanations have been proposed for the origin of massive star magnetic fields, both variants on the idea of a so-called “fossil” magnetic field, which is generated at some point in the star’s past and then locked in to the star’s outer portion.
The first hypothesis is that the magnetic field is generated while the star is being formed; the second is that the magnetic field originates in dynamos driven by the violent mixing of stellar plasma when the two stars in a close binary merge.
“This discovery doesn’t change the basic statistics that the BinaMIcS collaboration has assembled and we still don’t know why there are so few magnetic, massive stars in close binaries,” said Shultz.
The research shows the strengths of the magnetic fields are similar in the two stars, however, their magnetic axes are anti-aligned, with the south pole of one star pointing in approximately the same direction as the north pole of the other.
“We’re not sure why that is yet, but it probably points to something significant about how the stars are interacting with one another. We’ll need to collect more data,” Shultz added.
The research was published in the journal Monthly Notices of the Royal Astronomical Society. (PTI)
‘Molecules’ made of light may be possible
Washington: Researchers have showed that by tweaking a few parameters of the binding process, photons could travel side by side as a sort of “molecule”, which could let scientists build objects out of photons in future.
In 2013, collaborators from Harvard, Caltech and Massachusetts Institute of Technology (MIT) found a way to bind two photons together so that one would sit right atop the other, superimposed as they travel.
Their experimental demonstration was considered a breakthrough, because no one had ever constructed anything by combining individual photons – inspiring some to imagine that real-life ‘Star Trek’ lightsabers were just around the corner.
Now researchers from National Institute of Standards and Technology (NIST) and University of Maryland, along with other collaborators, showed theoretically that by tweaking a few parameters of the binding process, photons could travel side by side, a specific distance from each other.
The arrangement is akin to the way that two hydrogen atoms sit next to each other in a hydrogen molecule.
“It’s not a molecule per se, but you can imagine it as having a similar kind of structure,” said NIST’s Alexey Gorshkov. “We’re learning how to build complex states of light that, in turn, can be built into more complex objects.
This is the first time anyone has shown how to bind two photons a finite distance apart,” Gorshkov said. However, Gorshkov said he is not optimistic that building a Jedi Knights’ lightsaber would be possible anytime soon.
The main reason is that binding photons requires extreme conditions difficult to produce with a roomful of lab equipment, let alone fit into a sword’s handle. Still, there are plenty of other reasons to make molecular light – humbler than lightsabers, but useful nonetheless, researchers said.
For example, engineers need a way to precisely calibrate light sensors, and Gorshkov said the findings could make it far easier to create a “standard candle” that shines a precise number of photons at a detector.
Perhaps more significant to industry, binding and entangling photons could allow computers to use photons as information processors, a job that electronic switches in your computer do today.
Not only would this provide a new basis for creating computer technology, but it also could result in substantial energy savings.
Phone messages and other data that currently travel as light beams through fibre optic cables has to be converted into electrons for processing – an inefficient step that wastes a great deal of electricity.
If both the transport and the processing of the data could be done with photons directly, it could reduce these energy losses, researchers said. Gorshkov said it will be important to test the new theory in practice for these and other potential benefits.
The study appears in the journal Physical Review Letters. (PTI)
10,000-year-old stone tools unearthed in US dig
Washington: Thousands of stone tools crafted at least 10,000 years ago have been unearthed during a standard archaeological survey to clear the way for construction near a mall in US.
“We were pretty amazed,” said archaeologist Robert Kopperl, who led the field investigation. “This is the oldest archaeological site in the Puget Sound lowland with stone tools,” he said.
The crews unearthed more than 4,000 stone flakes, scrapers, awls and spear points crafted at least 10,000 years ago by some of the region’s earliest inhabitants, ‘The Seattle Times’ reported.
The discovery is yielding new insights into the period when the last ice age was drawing to a close and prehistoric bison and mammoths still roamed what is now Western Washington.
The site on the shores of Bear Creek, a tributary to the Sammamish River, appears to have been occupied by small groups of people who were making and repairing stone tools, said Kopperl, of SWCA Environmental Consultants.
Chemical analysis of one of the tools showed traces of the food they were eating, including bison, deer, bear, sheep and salmon. The site near Redmond Town Center mall in Redmond, Washington was initially surveyed in 2009, in a project to restore salmon habitat in Bear Creek, which had been confined to a rock-lined channel decades before.
The first discoveries were an unremarkable assortment of artifacts near the surface, Kopperl said. However, when the crews dug deeper, they found a foot-thick layer of peat. Radiocarbon analysis showed that the peat, the remains of an ancient bog, was at least 10,000 years old.
“We knew right away that it was a pretty significant find,” said Washington State Historic Preservation Officer Allyson Brooks. (PTI)
