Space & Physics
Massive stars bully a baby solar system
Massive stars in the Orion nebula exert intense radiation pressures to drive gas out from a young star system still forming planets.
Astronomers observed a young star system losing planet-forming gas to intense radiation from luminous stars right beside it.
The protoplanetary disc, dubbed d203-506, is located in the Orion stellar nursery, about 1,500 light years away.
It’s the closest star-formation region to us in the Milkyway.
Astronomers discovered d203-506 losing gas too quickly, for gas giant planets like Jupiter to form.
The Orion nebula sees massive stars born, that can outshine our sun by 100,000 times. The intense radiations can exert physical pressure to the gas – causing photoevaporation.
The high stellar radiation pressure has long been known to affect neighboring star and planet formations. Although in the latter case, it’s the first time that planet formation actually suffered from the intense radiation pressure.
The observations were carried out, analyzed and reported by an international team of astrophysicists, led by Dr Olivier Berné from the National Centre for Scientific Research (CNRS), France. JWST observations in the near-infrared wavelength range was combined with the longer radio wavelength coverage by Atacama Large Millimeter Array (ALMA).
The paper was published in Science on 29th February.
Space & Physics
The Story of the World’s Most Underrated Quantum Maestro
As the world celebrates the 131st birth anniversary of S.N. Bose, EdPublica explores the theoretical physicist’s unparalleled contributions to the field of quantum mechanics
It’s 1924, and Satyendra Nath Bose, going by S.N. Bose was a young physicist teaching in Dhaka, then British India. Grappled by an epiphany, he was desperate to have his solution, fixing a logical inconsistency in Planck’s radiation law, get published. He had his eyes on the British Philosophical Magazine, since word could spread to the leading physicists of the time, most if not all in Europe. But the paper was rejected without any explanations offered.
But he wasn’t going to give up just yet. Unrelenting, he sent another sealed envelope with his draft and this time a cover letter again, to Europe. One can imagine months later, Bose breathing out a sigh of relief when he finally got a positive response – from none other than the great man of physics himself – Albert Einstein.
In some ways, Bose and Einstein were similar. Both had no PhDs when they wrote their treatises that brought them into limelight. And Einstein introduced E=mc2 derived from special relativity with little fanfare, so did Bose who didn’t secure a publisher with his groundbreaking work that invented quantum statistics. He produced a novel derivation of the Planck radiation law, from the first principles of quantum theory.
This was a well-known problem that had plagued physicists since Max Planck, the father of quantum physics himself. Einstein himself had struggled time and again, to only have never resolved the problem. But Bose did, and too nonchalantly with a simple derivation from first principles grounded in quantum theory. For those who know some quantum theory, I’m referring to Bose’s profound recognition that the Maxwell-Boltzmann distribution that holds true for ideal gasses, fails for quantum particles. A technical treatment of the problem would reveal that photons, that are particles of light with the same energy and polarization, are indistinguishable from each other, as a result of the Pauli exclusion principle and Heisenberg’s uncertainty principle.
Fascinatingly, last July marked the 100 years since Einstein submitted Bose’s paper, “Planck’s law and the quantum hypothesis” on his behalf to Zeitschrift fur Physik.
Fascinated and moved by what he read, Einstein was magnanimous enough to have Bose’s paper translated in German and published in the journal, Zeitschrift für Physik in Germany the same year. It would be the beginning of a brief, but productive professional collaboration between the two theoretical physicists, that would just open the doors to the quantum world much wider. Fascinatingly, last July marked the 100 years since Einstein submitted Bose’s paper, “Planck’s law and the quantum hypothesis” on his behalf to Zeitschrift fur Physik.
With the benefit of hindsight, Bose’s work was really nothing short of revolutionary for its time. However, a Nobel Committee member, the Swedish Oskar Klein – and theoretical physicist of repute – deemed it a mere advance in applied sciences, rather than a major conceptual advance. With hindsight again, it’s a known fact that Nobel Prizes are handed in for quantum jumps in technical advancements more than ever before. In fact, the 2001 Nobel Prize in Physics went to Carl Wieman, Eric Allin Cornell, and Wolfgang Ketterle for synthesizing the Bose-Einstein condensate, a prediction made actually by Einstein based on Bose’s new statistics. These condensates are created when atoms are cooled to near absolute zero temperature, thus attaining the quantum ground state. Atoms at this state possess some residual energy, or zero-point energy, marking a macroscopic phase transition much like a fourth state of matter in its own right.
Such were the changing times that Bose’s work received much attention gradually. To Bose himself, he was fine without a Nobel, saying, “I have got all the recognition I deserve”. A modest character and gentleman, he resonates a lot with the mental image of a scientist who’s a servant to the scientific discipline itself.
He was awarded the Padma Vibhushan, the highest civilian award by the Government of India in 1954. Institutes have been named in his honour, but despite this, his reputation has little if no mention at all in public discourse.
But what’s more upsetting is that, Bose is still a bit of a stranger in India, where he was born and lived. He studied physics at the Presidency College, Calcutta under the tutelage that saw other great Indian physicists, including Jagdish Chandra Bose and Meghnad Saha. He was awarded the Padma Vibhushan, the highest civilian award by the Government of India in 1954. Institutes have been named in his honour, but despite this, his reputation has little if no mention at all in public discourse.
To his physicists’ peers in his generation and beyond, he was recognized in scientific lexicology. Paul Dirac, the British physicist coined the name ‘bosons’ in Bose’s honor (‘bose-on’). These refer to quantum particles including photons and others with integer quantum spins, a formulation that arose only because of Bose’s invention of quantum statistics. In fact, the media popular, ‘god particle’, the Higgs boson, carries a bit of Bose as much as it does of Peter Higgs who shared the 2013 Nobel Prize in Physics with Francois Euglert for producing the hypothesis.
Space & Physics
New Dust Models Shed Light on the End Stages of Sun-like Stars
New Insights into Hydrogen-Deficient Stars: Study of Planetary Nebula IC 2003 Reveals Key Evolutionary Clues
Careful modelling of the thermal and ionization structure of planetary nebulae, based on observations from the Vainu Bappu Telescope in Kavalur, Tamil Nadu, India, has enabled astronomers to deepen their understanding of the formation and evolution of these unusual hydrogen-deficient stars.
Planetary nebulae are shells of gas and dust ejected by stars like our Sun after they exhaust the hydrogen and helium fuel in their cores—a fate our Sun is expected to face in approximately 5 billion years. As the star’s core contracts due to the lack of nuclear fusion, it heats up and emits intense far-ultraviolet radiation. In the past, these stars appeared planet-like when viewed through small telescopes, a resemblance that led to their name.
While most stars in this late phase of their lives produce core remnants surrounded by tiny residual hydrogen envelopes, about 25% of them exhibit a deficiency of hydrogen and are instead rich in helium on their surfaces. Some of these stars also display strong mass loss and emission lines of ionized helium, carbon, and oxygen, characteristics identified as Wolf-Rayet (WR) features.
IC 2003, a rare planetary nebula, features a hydrogen-deficient central remnant star with WR characteristics.
Although the evolutionary status of typical central stars of planetary nebulae is well-understood, the mechanisms behind the formation of hydrogen-poor stars remain largely unclear. The physical and chemical structures of the nebulae surrounding these stars provide valuable clues about their origin and evolution, making it essential to study their gas and dust in detail.
To investigate this further, astronomers from the Indian Institute of Astrophysics (IIA), an autonomous institute under the Department of Science and Technology, observed IC 2003 using the optical medium-resolution spectrograph (OMR) attached to the 2.3-meter Vainu Bappu Telescope at the Vainu Bappu Observatory in Kavalur, Tamil Nadu. “We also used ultraviolet spectra from the IUE satellite and broadband infrared fluxes from the IRAS satellite archives for this study,” said K. Khushbu, the lead author and Ph.D. student. These combined observations provided critical insights into the role of gas and dust in shaping the thermal structure of the nebula, ultimately enabling the team to derive precise parameters for the central star.
The models they used revealed that the nebula’s parameters, including the ionizing source’s mass and temperature, were significantly different from those predicted by dust-free models. “This study highlights the importance of dust grains in the thermal balance of ionized gas and helps explain the large temperature variations seen in nebulae, which are often key to resolving abundance discrepancies in astrophysical nebulae,” explained Prof. C. Muthumariappan, the supervisor and co-author of the study. “We used a one-dimensional dusty photo-ionization code, CLOUDY17.3, to simulate data from ultraviolet, optical, and infrared observations,” he added.
By modeling the photoelectric heating of the nebula caused by the dust grains, the researchers were able to replicate the thermal structure observed in the planetary nebula. “We even reproduced the large temperature gradient typically seen in nebulae with WR stars. Our determination of element abundances, such as helium, nitrogen, and oxygen, differs significantly from the values obtained empirically,” Khushbu noted.
The study also provided accurate grain size distributions within the nebula and highlighted the crucial role of photoelectric heating in explaining temperature variations. From their models, the researchers derived accurate values for the luminosity, temperature, and mass of the central star. They concluded that the star’s initial mass was 3.26 times that of the Sun, indicating it was a more massive star.
This research advances our understanding of the complex processes at work in the evolution of hydrogen-deficient stars and offers valuable insights into the origins of the unique features observed in planetary nebulae.
Space & Physics
MIT team finds the smallest asteroids ever detected in the main belt
This marks the first time such small asteroids in the asteroid belt have been spotted, potentially leading to better tracking of near-Earth objects that could pose a threat
Asteroids that could potentially impact Earth vary greatly in size, from the catastrophic 10-kilometer-wide asteroid that caused the extinction of the dinosaurs to much smaller ones that strike far more frequently. Now, an international team of researchers, led by physicists at MIT, has discovered a new way to spot the smallest asteroids in our solar system’s main asteroid belt, which could provide critical insights into the origins of meteorites and planetary defense.
The team’s breakthrough approach allows astronomers to detect decameter asteroids—those just 10 meters across—much smaller than those previously detectable, which were about one kilometer in diameter. This marks the first time such small asteroids in the asteroid belt have been spotted, potentially leading to better tracking of near-Earth objects that could pose a threat.
“We have been able to detect near-Earth objects down to 10 meters in size when they are really close to Earth,” said lead author Artem Burdanov, a research scientist at MIT’s Department of Earth, Atmospheric and Planetary Sciences. “We now have a way of spotting these small asteroids when they are much farther away, so we can do more precise orbital tracking, which is key for planetary defense.”
The team used their innovative method to detect over 100 new decameter asteroids, ranging from the size of a bus to several stadiums wide. These are the smallest asteroids ever found in the main asteroid belt, located between Mars and Jupiter, where millions of asteroids orbit.
The findings, published today in Nature, have the potential to improve asteroid tracking efforts, which are critical for understanding the risk of future impacts. Scientists hope that the method could be applied to identify asteroids that may one day approach Earth.
The research team, which includes MIT planetary science professors Julien de Wit and Richard Binzel, as well as collaborators from the University of Liege, Charles University, and the European Space Agency, among others, utilized the James Webb Space Telescope (JWST) for their discovery. JWST’s sensitivity to infrared light made it an ideal tool for detecting the faint infrared emissions of asteroids, which are far brighter at these wavelengths than in visible light.
The team’s approach also relied on an imaging technique called “shift and stack,” which involves aligning multiple images of the same field of view to highlight faint objects like asteroids. This technique was originally developed for exoplanet research but was adapted for asteroid detection.
The researchers believe that these new findings will help improve our understanding of asteroid population
By processing over 10,000 images of the TRAPPIST-1 system—collected to study the planets in that distant star system—the researchers identified eight known asteroids and an additional 138 new ones. These newly discovered asteroids are the smallest main belt asteroids ever detected, with diameters as small as 10 meters.
“This is a totally new, unexplored space we are entering, thanks to modern technologies,” Burdanov said. “It’s a good example of what we can do as a field when we look at the data differently. Sometimes there’s a big payoff, and this is one of them.”
The researchers believe that these new findings will help improve our understanding of asteroid populations, including the many small objects that result from collisions among larger asteroids. Miroslav Broz, a co-author from Charles University in Prague, emphasized the importance of studying these decameter asteroids to model the creation of asteroid families formed from larger, kilometer-sized collisions.
De Wit, a co-author, highlighted the significance of the discovery: “We thought we would just detect a few new objects, but we detected so many more than expected, especially small ones. It is a sign that we are probing a new population regime, where many more small objects are formed through cascades of collisions.”
(With inputs from MIT)
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