Thursday, June 20, 2019

370 light years away, astronomers discover the new "solar system"

Astronomers successfully captured two exoplanets. They were born in a protoplanetary disk that surrounds a young star (the protoplanetary disk is a dense gas surrounded by newly formed young stars). The gravitational force of the planet itself drags the planet disk during the movement and draws a huge gap. This marks the birth of a new "solar system".
370 light years away, astronomers discover the new "solar system"
Julien Girard, a researcher at the US Space Telescope Research Institute, said: "This is the first direct capture of a dual planetary system with a planetary disc gap."Although more than a dozen exoplanets have been photographed directly, the newly discovered stellar system numbered PDS 70 is the second multi-planet system discovered (the first is the four-planet system of the stellar HR 8799). Unlike the HR 8799, the planets in the PDS 70 continue to grow.The central star of the PDS 70 is about 370 light years from Earth. This star has been formed for more than six million years, and is smaller than our sun, but it is still growing in interstellar gas. The planet disk around it has a lot of gas and dust, and there is a big gap, the inner edge is 1.9 billion miles from the center star and the outer edge is 3.8 billion miles.

The innermost planet PDS 70b known in the PDS 70 stellar system is located in the interplanetary space of approximately 2 billion miles from the central star, and its orbit is similar to Uranus in our solar system. Researchers estimate that it weighs 4 to 17 times as much as Jupiter. It was first discovered in 2018.The PDS 70c is a newly discovered planet located near the outer edge of the planet's disc gap, about 3.3 billion miles from the center star, similar to the distance between Neptune and the Sun. It is lighter than the planet PDS 70b, about 1 to 10 times that of Jupiter. The two planet orbits are close to a 2:1 resonance, which means that the planet PDS 70b will circumscribe twice during the time that the planet PDS 70c is around the center star.This new discovery is very important because it directly proves that the newly formed planet can create a gap in the planet disk. "At present, there are gaps on the planet disks seen by large ground and space optical telescopes such as the Atacama Radio Telescope Array (ALMA) and the Hubble Space Telescope. Many people are thinking about whether there is a gap in the gap. Newly generated planets? Our observations affirm this view,” Gillard explained.The team detected the PDS 70c using the Very Large Telescope of the European Southern Observatory. Using the extremely high spatial resolution and excellent spectral resolution provided by an 8-meter telescope equipped with four lasers, the research team is able to lock the spectrum emitted by hydrogen atoms, marking the accumulation of interstellar gas (accumulation refers to the attraction of the celestial body) The process of continuously attracting and accumulating substances such as gas and dust in the surrounding space."This new observation technique was developed to better distinguish between galaxies and clusters. But it can also be used for exoplanet imaging." The first author of the article, Sebastian, Ph.D. student at the Leiden Observatory in the Netherlands · Sebastiaan Haffert said, "We were very surprised when we found the second planet."




In the pre-merger hotline, astronomers first discovered the "wave bridge" between the two clusters.

We know that there are actually a series of "bridges" connected between the various galaxies and clusters of the universe. They are composed of dark matter, dust and gas, forming an orderly universe. Recently, astronomers have for the first time discovered a special "radio wave bridge" between two clusters of galaxies, stretching over 10 million light years and carrying magnetic fields, allowing scientists to learn more about the large-scale structure of the universe.
In the pre-merger hotline, astronomers first discovered the "wave bridge" between the two clusters.
In cosmic physics, fibrous structures are the largest known structures. These "fibers" are assumed to be composed of invisible dark matter and visible dust and gas. You can imagine that the structure of the universe is like a net, and those lines are thin. And the fibrous structure that is difficult to observe, the point where the line intersects the line is a galaxies or clusters of galaxies. As for the one-frame-shaped holes between the lines, we call them "Voids". These areas (interstellar) Space) basically no galaxies.So far, we have found in the "points" those galaxies and galaxies (except visible light, infrared, X-ray, gamma rays, radio, etc.) that are filled with hot gases and stars, in contrast to fibers. Although the length of the structure can extend hundreds of millions of light years, it is relatively elusive, and scientists have never observed a magnetic field in these filamentous structures.However, the team led by the Italian Institute of Astrophysics (INAF) astronomer Federica Govoni, after observing the Abell 0399 and Abell 0401 clusters using the Low-Frequency Array (LOFAR) radio telescope, was surprised to find two clusters. Connect the "Radio Wave Bridge".Before the study, scientists already knew that the two clusters were surrounded by radio magnetic fields, and the Planck satellite recently confirmed that the two clusters were connected to each other through the slender fibrous structure, which triggered researchers' curiosity and speculation whether the magnetic field of the galaxy cluster had Filaments that may extend beyond the point? It turns out that the researchers are bet on it. Abell 0399, Abell 0401 These two clusters of galaxies are currently about 9.8 million light-years apart, about 1 billion light-years away, and are destined to collide and merge into a larger superclusters in the future, when researchers observe the cluster of galaxies. During the interstellar space, an obvious "radio wave bridge" was found connecting two clusters.After further computer simulations, the researchers proposed a possible explanation for this phenomenon. This radio wave emits a strong shock wave from a weak magnetic field (one million times weaker than the Earth's magnetic field), and then accelerates a large number of electrons into relativistic particles (close to Particles moving at the speed of light) ran between two clusters of galaxies along a fibrous structure.In other words, the Abell 0399, Abell 0401 clusters are busy disrupting each other, throwing shock waves and a large number of relativistic particles into the intergalactic space.The magnetic field of fibrous structures often exceeds the detection limits of today's telescopes, so researchers are not sure whether all fibrous structures have magnetic fields, and as future observations may help astronomers understand more about how large-scale structures of the universe are formed.


Japanese astronomers discovered more than 1,800 supernovas in six months

After Japanese researchers gathered data, they discovered about 1,800 new supernovas or exploding stars in half a year. These studies have helped to measure the speed of the expansion of the universe, which is a very surprising discovery.
Japanese astronomers discovered more than 1,800 supernovas in six months
According to comprehensive media reports, supernovae are extremely rare. Only a few telescopes in the world can capture clear images. Even with the Hubble Space Telescope, it takes 10 years to discover 50 supernovas that are more than 8 billion light-years away from Earth. Researchers at the Kafiri Mathematical Cosmology Research Institute (Kavli IPMU) at the University of Tokyo, Japan, combined with the observations of the new generation of super wide-angle cameras (HSC) and the Pleiades telescope (also known as the Subaru Telescope), found 1,800 supernovae. Among them, 58 are type Ia supernovas 8 billion light-years away from the Earth.

Supernova is a violent explosion that some stars experience as they approach the end of the evolution. These explosions are extremely bright. They are 1 billion times brighter than the sun at any time during the explosion. Ia supernovas are very practical because of their constant maximum brightness. It helps researchers calculate the distance from the star to the Earth, which is most beneficial to researchers who want to measure the rate of expansion of the universe.

In addition to the Ia supernova, researchers have begun to study "super-luminous supernovae" 5 to 10 times brighter than it, and its unusual brightness can help researchers discover distant stars.


Friday, June 14, 2019

Astronomers capture images of this binary system as the asteroid 1999 KW4 flies across the Earth

The 1999 KW4 asteroid passed the Earth at a safe distance of about 3.2 million miles. Space rock is far from enough to pose a threat to our planet, but this distance is enough for astronomers to capture the image of this "special visitor."
 Astronomers capture images of this binary system as the asteroid 1999 KW4 flies across the Earth
Asteroid 1999 The KW4, unlike many other space rocks, is actually a binary system consisting of two separate space rocks: an asteroid about a mile in diameter and a small satellite that orbits it. The satellite is about 0.25 miles in diameter.

The European Southern Observatory has released an image of a binary system taken by the Very Large Telescope (VLT). The image of the dragonfly is the actual photograph taken by the scientist, and the image on the right is the artist's imagination of the artist about what they might look like.

"These data, combined with all the data obtained through the International Asteroids Early Warning Network (IAWN) activities on other telescopes, are critical to assessing effective deflection strategies when it is found that asteroids collide with the Earth," European Southern Observatory astronomer Olivier Hainaut said in a statement. “In the worst case, this knowledge is also essential for predicting how asteroids interact with the atmosphere and the Earth's surface, so that we can mitigate damage in the event of a collision.”






Astronomers say that the water found in the "Christmas Comet" is very similar to the water in the Earth.

Where does the water on the planet come from? This problem has been plaguing scientists for many years. An international team of astronomers tried to answer this question by studying the water found in the comet 46P / Wirtanen.
 Astronomers say that the water found in the "Christmas Comet" is very similar to the water in the Earth.

We have identified a huge reservoir on the periphery of the solar system, where the water is very similar to the water on Earth. "The first author of the study, Darek Lis, said in a statement.The study was published in the journal Astronomy and Astrophysics on May 20, and astronomers used NASA's Stratospheric Infrared Astronomical Observatory (SOFIA) to study the so-called "Christmas Comet" in 2018. Flying in the earth in December. The SOFIA Air Observatory was converted from a Boeing 747.A long-standing theory holds that the earth's water is from ice comets outside the solar system. The theory holds that when a comet collides with the early Earth, the impact brings water into the Earth's environment. To determine if the water in this comet is similar to the water on Earth, astronomers used SOFIA to observe 46P / Wirtanen and analyzed the ratio between the two different types of water.

The water molecules we know are composed of two hydrogen atoms and one oxygen atom. This form of water molecules constitutes most of the water found on Earth. There are only three isotopes of hydrogen: (P) has one proton in the nucleus, no neutron; (D) has one proton and one neutron in the nucleus; (T) has one proton in the nucleus, 2 Neutron. But an unusual water, heavy water, is a compound of strontium and oxygen. The two hydrogen isotopes in the heavy water molecule are one more neutron than the normal hydrogen atom. Studying the ratio of strontium to hydrogen (D / H ratio) can provide astronomers with more information about the origin of water.




The D/H ratio of comets is usually one to three times higher than the ratio of the Earth's oceans, but astronomers have found that the ratio of 46P / Wirtanen is basically the same as what we see on Earth.The previous two comets, 103P/Hartley 2 and 45P/H-M-P, showed similar proportions. It is worth noting that all three are classified as “extremely active comets”, which release water on the surface and in the atmosphere as they approach the temperature of the sun. The team found that the D/H ratios in these three were related to the water present in the atmosphere. As a result, they believe that all comets may contain earth-like water locked in rock.This discovery has once again opened the debate about the earth's water source. Other comets originated from the Oort cloud at the edge of the solar system and did not exhibit similar D/H ratios.




Astronomers discover dozens of stars that have been "expelled from their homes"

According to foreign media BGR reports, astronomers used NASA's powerful Chandra X-ray Observatory to observe that some stars are often "expelled from their homes." Astronomers have discovered several binary systems. These binary stars consist of two stars that orbit around a common center.
   Astronomers discover dozens of stars that have been "expelled from their homes"
When a giant star explodes into a supernova and its core collapses into a dense neutron star, under certain conditions, these huge explosions that produce neutron stars are not symmetrical. "Asymmetric forces" may cause a star to be thrown at its intended location. And their companion stars will also be forced to leave the galaxy.

“It’s like a guest being invited to a party with a noisy friend,” Xiangyu Jin, the first author of the study, said in a statement. "The companion star in this case was dragged out of the galaxy just because it was in orbit with the supernova's star."

Researchers using Chandra data have discovered about 30 pairs of stars from the Fornax cluster, and because of this phenomenon, these stars appear to be speeding away from their "homes."

Looking ahead, the researchers hope to use other data from Chandra to discover other pairs of expelled stars that are too dim to use existing data. Longer observations may change this, revealing how additional binary stars are expelled into space.


Astronomers discover rare new galaxies on the verge of death

For the first time, an astrophysicist at the University of Kansas discovered an extremely rare galaxy that fundamentally changed the understanding of galaxies' deaths. At the 234th meeting of the American Astronomical Society on Thursday, Allison Kirkpatrick showed off her "cold quasar", a very bright, dying galaxy.

 Astronomers discover rare new galaxies on the verge of death

The center of the quasar is basically a huge supermassive black hole surrounded by a large amount of gas and dust. The surrounding material releases huge energy in the process of rapidly falling into the black hole in a way similar to "friction heat generation", making them super bright. - Brighter than ordinary galaxies. They can be generated when two galaxies are merged.Eventually, gas and dust will begin to fall into the center of the quasar and be blown into space. Astronomers speculate that this is basically the end of a galaxy's life, it has lost the ability to form new stars, and become "passive", but Kirkpatrick and her research team found that these cold quasars A small number of stars are also formed in a small part.

Using X-ray and infrared telescopes, the researchers found that 22 quasars from the Earth's 6 to 12 billion light years showed unusual characteristics. From an optical point of view, they look like they are in the final stages of "life." However, they still emit bright far infrared rays, which contain a lot of dust and gas.

“These galaxies are very rare because they are in transition,” Kirkpatrick said in a press release. "We have discovered them before the star formation in the Milky Way is extinguished. This transition period should be very short.