Login with your Social Account

Astronomers Have Discovered a Peculiar Rocky Exoplanet With Three Glowing Red Suns

Astronomers have discovered a strange rocky exoplanet in a triple-star system

Astronomers have recently discovered a new strange rocky Exoplanet in a triple star system. Our sun is the only star in our solar system, but out in the wider universe stars often are locked in a dance with other stars and orbit at a mutual centre of gravity.

A catchy name was allotted, LTT 1445Ab since it orbits the primary star of the three red dwarfs of system LTT 1445, located around 22.5 light-years away from earth. Astronomer Jennifer Winters of the Harvard-Smithsonian Center said that on standing on that planet’s surface, there will be three suns in the sky with two of them far away and small in size. The paper is submitted to The Astronomical Journal and can found on arXiv.

The planet was discovered by TESS, the planet-hunting space telescope of NASA which is designed to find exoplanets that pass between us and their home star by detecting the telltale dimming since the planet blocks a certain percentage of light. Scientists can place constraints on mass and size of the planet due to the depth of dimming, tiny star movements since it is slightly pulled by the gravity of planet.

The LTT 1445Ab varies from the HD131399Ab which was discovered back in 2016. It was bigger with a 550-year orbit around one of the star in a triple system 340 light-years away from earth. The new planet is only 1.35 times the size of Earth and 8.4 times Earth’s mass and thus is denser than Earth.

The size and mass put it in the category of rocky planets like Mars, Venus etc. and is not a gas or ice giant. The chances of habitability are low. The surface temperature is expected to reach scorching 428 Kelvin and it whips around its star once every 5.36 Earth days.

Astronomers predict that LTT 1445Ab might have an atmosphere like any other rocky planet and might be a good place to test the detection of gases like methane and carbon dioxide. The atmosphere dims the starlight and can also change it based on chemical composition. The atmospheric components can be found out based on the spectrum of light through the atmosphere.

The current technology is not well developed for this task but may become possible with the Hubble’s successor, the James Webb Space Telescope which will launch in 2021. LTT 1445Ab is a good candidate for observations as there will be plenty of observations and is relatively very close in a cosmic scale at a distance of 22.5 light-years away. The dwarf star is bright enough to back-light the atmosphere but not bright enough to outshine the planet. Rocky planets are relatively common in the close orbits around red dwarf stars. Hence, looking at the LTT1445Ab closer can tell us what to expect on such planets.

Journal Reference: arXiv

single atomic layer graphite

Researchers discover quantum phenomenon to understand fundamental limits of graphene electronics

Scientists from the University of Manchester, Nottingham and Loughborough have discovered a quantum phenomenon for understanding the fundamental limits of graphene electronics. It describes the way electrons in one atomic-thin sheet of graphene scatter the vibrating carbon atoms that make the hexagonal crystal lattice. The study has been published in Nature Communications.

Applying magnetic field perpendicular to graphene plane, current-carrying electrons are forced to move in the “cyclotron orbits” which are closed and circular. In pure graphene, electrons escape from the orbit by bouncing off “phonon” while scattering. Phonons are particle-like bundles of momentum and energy and are “quanta” of sound waves that are associated with vibrating carbon atom. When graphene crystal is warmed from very low temperature, they are generated in large numbers.

The team passed a small electric current through graphene sheet for precisely measuring the amount of momentum and energy which is transferred between electron and phonon while scattering. It revealed that two kinds of phonons scatter electrons, transverse acoustic (TA) phonons where carbon atoms vibrate perpendicular to the direction in which phonon propagates and wave motion and longitudinal acoustic phonons (LA) where carbon atoms vibrate in the direction of phonon and wave motion. These accurately measure the speeds of two kinds of phonons which is difficult to make in a single atomic layer. It also shows that TA phonon scattering dominates LA phonon scattering.

This phenomenon is termed as magnetophonon oscillation and it was measured in many semiconductors several years before graphene was discovered. It has been known longer than the quantum Hall effect and is one of the oldest quantum transport phenomena.

Roshan Krishna Kumar and Laurence Eaves, co-authors in the work said that they were surprised to discover such magnetophonon oscillations in graphene and at the same time confused why it had not been discovered before in graphene. It had two key requirements. Scientists had to fabricate high-quality transistors of graphene having large areas at National Graphene Institute. It had not been discovered if the device dimensions were smaller than a few micrometers. 

Piranavan Kumaravadivel, University of Manchester and lead author of the paper said that macroscopic, millimeter-sized crystals were studied at the beginning of quantum transport experiments. The studied devices in most work on quantum transport on graphene are normally a few micrometers in size. Larger graphene devices are important for both applications and fundamental studies. 

The next ingredient is temperature. Graphene quantum transport experiments are carried out at ultra-cold temperatures for slowing the carbon atoms which are vibrating and “freeze-out” the phonons which break quantum coherence. So graphene is warmed so that phonons are active to cause the effect.

Mark Greenaway, Loughborough University who also worked on the quantum theory of this effect said that the result is quite exciting as it opens a new route for understanding the phonon properties in two-dimensional crystals and heterostructures. It will also help to understand electron-phonon interactions in promising materials which is vital for new devices and applications.

Research Paper: https://www.nature.com/articles/s41467-019-11379-3

heat wave alaska

Giant heat dome over Alaska about to break all-time temperature records

Alaska is setting all-time heat records in recent days as a massive and abnormally intense area of high pressure is locked in and strengthening the region around it. It is expected to create temperature records as the highest value recorded for several days mainly in Southern Alaska.

Anchorage has recorded its highest temperature of 85 degrees Fahrenheit which was recorded in 1969 for 5 consecutive days. It could even touch 90 degrees Fahrenheit. The National Weather Service has predicted the temperature in southern Alaska to be in the 80 degrees Fahrenheit and even in the low 90s. The lowest temperature could touch only close to 60 degrees Fahrenheit at nights during this hot stretch and close to the average temperature at this point of time in the year. It is the warmest period for Alaska and is expected to last close to 7 days.

The heat wave is the latest in a nonstop barrage of warm weather for Alaska. It comes on the end of June where the temperature was already above average and was filled with calamities like wildfires which continue even as July arrives. The spring and winter before that were also pretty warm. It also follows the heat wave that hit Europe and shattered records for highest temperatures there as well.

The temperatures at Alaska have shifted abruptly in the past few years and there is a similar change across the Arctic Region due to climate change and global warming. The sea ice surrounding the state has recorded the lowest levels. The presence of open water and the absence of ice has elevated the ocean temperature close to 2.5 degrees Celsius above normal temperature. The combination of the high-pressure heat dome and unusually high coastal waters and maximum energy from the sun will play the role of contributing factors to maximize the potential for historically high temperatures.

A climatologist from Alaska has tweeted that Anchorage, Kotzebue, Talkeetna, and Yakutat have posted the warmest temperatures in the month of June as per record while Nome, King Salmon, and McGrath have logged the second warmest June as per records. The high temperatures have led to a higher monthly temperature average and have hit 92 degrees Fahrenheit near the Northway, near the eastern border with Canada. In southeast Alaska, drought has persisted for close to a year now with Juneau recorded the third warmest day and also completed the warmest five day stretch since 1936. This heat blast is expected to eventually ease by next week and forecast predicts normal temperature in July and August.

Hope Diamonds

Ocean floor sediments recycle to form salty diamonds

As per the reports of a new study by a team of geoscientists from Macquarie University, Sydney, salt traces trapped in many diamonds reveal on analysis that the stones are produced from the seabeds which have been trapped inside the Earth’s crust for countless years.

A majority of the diamonds which are found on the surface of the Earth are formed in this manner while the others are formed due to the melt crystallisation quite deep in Earth’s mantle. In the experiments, researchers from Goethe Universität and Johannes Gutenberg Universität of Germany simulated the high pressures and temperatures which exist 200 kilometres deep inside the Earth. They found that the seawater which is present in the sediment at the ocean’s bottom reacts in the right way to form the salts which are present in the diamonds.

The study has been published in the journal Science Advances and it clears a major confusion about the way diamonds are formed. It was earlier thought that the salts within diamonds originated from the marine seawater. However, the research cleared that they originated from the marine sediment.

Diamonds are classified into gem diamonds and fibrous diamonds. Gem diamonds are fully composed of carbon in its purest form while fibrous diamonds contain the traces of elements such as sodium, potassium which can disclose a lot of information about the conditions in which their formation took place. Fibrous diamonds normally grow faster than gem diamonds which indicates that small samples of fluids are trapped during formation.

Samples of marine sediment were placed inside a vessel containing a rock called peridotite. It is the most common type of rock which is present in the mantle where diamonds are formed. Pressure and heat were increased and the adequate time to react with one another was given matching the conditions of the mantle.

At values of pressure lying between four and six gigapascals and temperatures in the range of 800 degrees to 1100 degree Celsius, which is equivalent to the depth of 120-180 kilometres inside Earth, salts were produced having the balance of sodium and potassium. It matched with the traces that are obtained inside diamonds.

Dr Michael Förster, lead author of the paper remarked that they have successfully demonstrated the sequence of steps which lead to the growth of diamonds and confirmed that the recycling of sediments in the ocean is responsible for it.