New Delhi: Scientists have discovered stars unexpectedly blasting out radio waves, suggesting the existence of hidden planets. Astronomers have found that a Jupiter-sized planet is orbiting a white dwarf star in the Milky Way, which provides clues as to how our solar system will be when the Sun eventually dies about five to six billion years later.
Also, observations made by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) have revealed the nature of unknown gamma-ray sources.
ABP Live brings you more interesting science news reported over the past week.
Radio Signals From Distant Stars Indicating Hidden Planets
Researchers from the University of Queensland and the Dutch national observatory ASTRON have recently discovered stars that are unexpectedly emitting radio waves, using the world's most powerful radio telescope Low Frequency Array (LOFAR) located in the Netherlands. The scientists were searching for planets when they came across this astonishing discovery.
The research was recently published in the Nature Astronomy journal. Dr. Benjamin Pope, one of the authors of the study, said they discovered signals from 19 distant red dwarf stars, according to a statement issued by the University of Queensland. Four of the red dwarf stars emitted signals which indicate that planets are orbiting them, he added. The planets of the solar system are known to emit powerful radio waves as a result of the interaction between magnetic fields of the planets with solar wind. But so far, radio signals from planets outside the solar system had not been detected, he explained.
He said the discovery is crucial to the field of radio astronomy, and could lead to the discovery of planets throughout the Milky Way Galaxy.
While making observations, radio astronomers can now see plain old stars, and can search for planets surrounding those stars using this data.
Dr Joseph Callingham, the lead author of the research, said the team is convinced the signals have arisen due to a magnetic connection of the stars and the unseen planets orbiting them, just like the interaction between Jupiter and its moon, Io.
He added that just like Earth's aurorae emit powerful radio waves, the recently detected radio waves are a result of the planets being enveloped in the magnetic field of their host stars.
Gas Giant Orbiting A Dead Star Provides Clues About Aftermath Of Sun's Demise
Astronomers have recently discovered the first confirmed planetary system that provides a glimpse about the expected aftermath of the Sun's demise in about five to six billion years.
The study was recently published in the Nature journal.
The researchers made the discovery using the WM Keck Observatory on Maunakea in Hawaii. They observed a white dwarf star near the centre of our Milky Way Galaxy, which is being orbited by a planet similar to Jupiter, with a Jupiter-like orbit.
Joshua Blackman, the lead author of the study, said the planetary system confirms the fact that planets can continue to exist even after their host star's death, if they are at a large enough distance from the star, according to a statement issued by WM Keck Observatory.
He added that the system was analogous to our own Solar System, and resembles the expected fate of our system. He explained that when the Sun turns into a red giant after running out of nuclear fuel, and self-destructs, Jupiter and Saturn may survive that phase.
However, Earth may not survive the red supergiant phase of the Sun as our planet is in proximity to the Sun, said David Bennett, co-lead author of the study.
When a star like our Sun dies, it burns off all the hydrogen in its core, turns into a red giant star, collapses into itself, and shrinks into a white dwarf.
The team of researchers ruled out the possibility of a neutron star or black hole host, which means that the planet is orbiting a dead star, or a white dwarf, and this offers a glimpse into the fate of the solar system after the disappearance of Earth due to the Sun's demise.
Nature Of Unknown Gamma-Ray Sources In The Blazing Sky Revealed
An international team of astronomers have discovered that most of the Gamma-ray emitting sources belong to the class of active galaxies known as blazars. The study was recently published in The Astronomical Journal.
The Fermi satellite has detected many celestial objects to date, one-third of which are unidentified gamma-ray sources.
Blazars are extremely rare, black hole-powered galaxies, which constitute the largest population of known gamma-ray sources. A supermassive black hole is located at the centre of a blazar, which sweeps matter in the form of powerful jets at the speed of light. Highly energetic gamma rays are emitted as a result of particles being accelerated in the jets, which have been detected by the Fermi satellite.
The researchers analysed hundreds of optical spectra collected by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), at the Xinglong Station in China.
The astronomers discovered Blazar Candidates of Uncertain type (BCUs), whose properties resemble those of blazars. The researchers, using the LAMOST archive data, classified many BCUs as blazars. They also found that the gamma-ray sources belong to the blazar class known as BL Lac objects.
The LAMOST archive led to the successful identification of gamma-ray sources with blazars, the scientists note.
Stellar Fossils In Meteorites Point To Distant Stars
A new study conducted by researchers from the Washington University in St. Louis has found the true stellar origins of a diverse set of presolar grains (interstellar matter which originated before the formation of the Sun). The study was recently published in The Astrophysical Journal Letters.
Presolar grains are present in some pristine meteorites, and are a record of the original building blocks of the solar system. This is because the grains formed in ancient stars which died before the birth of the Sun.
Determining the type of star these grains originated from is a challenge for astronomers.
Liu Wang, the lead author of the study, along with her team, analysed Nitrogen and Magnesium-Aluminium isotopes present in presolar silicon carbide (SiC) grains, using a spectrometer called NanoSIMS, and obtained the true stellar signatures.
They found that the grains are linked to different types of carbon stars.
The scientists also inferred that the grains initially had large amounts of radioactive isotope of aluminium-26, which was an important heat source for young planetary bodies in the early Solar System, and also in other extra-solar systems. The researchers found that the parent stars of the grains produced this isotope.
Thus, the study links some presolar grains to the lesser known carbon stars, and finds clues about the hydrogen-burning processes occuring in such carbon stars, all of which will help astronomers better understand the evolution of stellar objects.