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The brightest supernova flashed in the constellation Dragon. This is a unique case in the history of the universe

A supernova flashed record-breaking brightly in the Universe – this had never happened before. The death of the star provoked a huge surge of energy and light, which surprised scientists a lot. Little is known so far, but the star’s story is more mysterious and cinematic. After all, an outbreak really happened a long time ago and in a distant, faraway galaxy.

On Monday, April 13, the science journal Nature Astronomy published a study on a supernova called SN2016aps. It flashed brighter than anything else, and there is a record holder in a distant, faraway dwarf galaxy in the constellation Dragon. The light from it goes to our Milky Way for about three billion years, that is, everything happened a long time ago (to the delight of the fans of the Star Wars saga).

The previous record was set by the SN 2006gy star, but the power of the new flash turned out to be almost two times higher – as well as the amount of energy released. One of the authors of the study, Matt Nicholl, astrophysicist from the University of Birmingham in the UK, explained:

We compare the power of supernovae on two scales – the total amount of energy released during the explosion, as well as how much of it is accounted for by visible light. Typically, this parameter is less than one percent for normal supernovae. In the case of the SN2016aps, it was about five times higher than normal. This event generated a record high amount of light.

The progenitor of the supernova was a huge star – ten times the size of the Sun (from 50 to 100 times – scientists determined only approximately). Therefore, its death provoked the release of a heap of energy and hot clouds of gas.

This event is unique for another reason. The supernova record holder could appear as a result of the merger of two massive stars before the explosion. Moreover, until now, such systems have not been confirmed by astronomical observations.

Even with SN2016aps, everything is not clear to the end. Astrophysicists were unable to determine exactly in which galaxy the star flashed, coming to a poetic but sad conclusion:

As if this supernova flickers alone in a secluded area of ​​space.

Scientists, according to Matt Nicholl, have generally had some problems with similar phenomena lately. She explained that researchers began to doubt that they understood well the physical principles that govern the birth of flares. Previously, they found “failed” supernovae. These are dying elderly stars that just disappeared from the sky. In parallel, astrophysicists are confused by unusually bright bursts that go beyond the theoretical limits of brightness.

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NASA has banned fighting and littering on the moon

New details of the agreement signed by representatives of a number of countries on the development of the moon and the extraction of minerals within the framework of the Artemis program have appeared. Reported by the National Aeronautics and Space Administration (NASA).

So, astronauts involved in the mission are prohibited from littering and fighting on the territory of a natural satellite of the Earth.

So, we present to you the new rules for being on the Moon:

Everyone comes in peace;

Confidentiality is prohibited, all launched objects must be identified and registered;

All travel participants agree to help each other in case of emergencies;

All received data is transferred to the rest of the participants, and space systems must be universal;

Historic sites must be preserved and all rubbish must be disposed of;

Rovers and spacecraft should not interfere with other participants.

“”It is important not only to go to the moon with our astronauts, but also that we bring our values ​​with us,” said Mike Gold, acting head of NASA’s international and inter-agency relations.

According to him, violators of the above rules will be asked to “just leave” the territory of the moon.

The effect of these principles so far applies to eight signatory countries of the agreement: the USA, Australia, Canada, Italy, Japan, Luxembourg, the United Arab Emirates and the United Kingdom. Countries other than China can join if they wish.

 It should be noted that at the moment NASA is prohibited from signing any bilateral agreements with the PRC leadership.

The first NASA mission to the moon, known as “Artemis 1”, is scheduled for 2021 without astronauts, and “Artemis 2” will fly with a crew in 2023.

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Methane snow found on the tops of Pluto’s equatorial mountains

Scientists believe that it arose as a result of the accumulation of large amounts of methane at an altitude of several kilometers above the surface of the planet.

In the images of the Cthulhu region – a dark region in the equatorial regions of Pluto – planetary scientists have found large reserves of methane snow that covers the peaks of local mountains and hills. It formed quite differently from how snow forms on Earth, astronomers write in the scientific journal Nature Communications.

“The white caps on the tops of Pluto’s mountains did not arise from the cooling of air currents that rise along the slopes into the upper atmosphere, as it happens on Earth, but from the accumulation of large amounts of methane at an altitude of several kilometers above Pluto’s surface. This gas condensed on the mountain tops, “the scientists write.

We owe almost everything we know about Pluto to the New Horizons interplanetary station. It was launched in January 2006, and in mid-July 2015 the station reached the Pluto system. New Horizons flew just 13 thousand km from the dwarf planet, taking many photographs of its surface. 

New Horizons data indicated an interesting feature of Pluto – in its depths, a giant subglacial ocean of liquid water can be hidden. It can be a kind of engine of those geological processes, traces of which can be seen on the surface of a dwarf planet. Because of this discovery of New Horizons, many discussions began among planetary scientists. Scientists are trying to understand how such a structure could have arisen, as well as to find out the appearance of Pluto in the distant past.

Members of the New Horizons science team and their colleagues from France, led by planetary scientist from NASA’s Ames Research Center (USA) Tanguy Bertrand, have discovered another unusual feature of Pluto. They studied the relief of one of the regions of the dwarf planet – the Cthulhu region. This is what astronomers call a large dark region at Pluto’s equator, which is whale-like in shape and is covered in many craters, mountains and hills.

Snow in Pluto’s mountains

By analyzing images of these structures taken by the LORRI camera installed on board New Horizons, astronomers have noticed many blank spots on the slopes of the highest mountain peaks. Having studied their composition, scientists have found that they consist mainly of methane.

Initially, planetary scientists assumed that these are deposits of methane ice. However, Bertrand and his colleagues found that the slopes and even the tops of Pluto’s equatorial mountains are actually covered not only with ice, but also with exotic methane snow that forms right on their surface.

Planetary scientists came to this conclusion by calculating how methane behaves in Pluto’s atmosphere. In doing so, they took into account how the molecules of its gases interact with the sun’s rays and other heat sources. It turned out that at the equator of Pluto, at an altitude of 2-3 km from its surface, due to the special nature of the movement of winds, unique conditions have formed, due to which snow is formed from methane vapor.

Unlike Earth, where such deposits are formed as a result of the rise of warm air into the upper atmosphere, on Pluto this process goes in the opposite direction – as a result of contact of the cold surface of the peaks and slopes of mountains with warm air masses from the relatively high layers of the dwarf planet’s atmosphere.

Previously, as noted by Bertrand and his colleagues, scientists did not suspect that this was possible. The fact is that they did not take into account that due to the deposition of even a small amount of methane snow and ice, the reflectivity of the peaks and slopes of mountains in the Cthulhu region increases. As a result, their surface temperature drops sharply, and snow forms even faster.

Scientists suggest that another mysterious feature of Pluto’s relief could have arisen in a similar way – the so-called Tartarus Ridges, located east of the Sputnik plain. A distinctive feature of this mountainous region is strange peaks that are shaped like skyscrapers or blades. Bertrand and his colleagues suggest that these peaks are also methane ice deposits that grow “from top to bottom.”

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First exoplanet discovered in another galaxy

The Chandra X-ray Space Telescope has found the first potential exoplanet in another galaxy. The planet orbits in a binary star system in a galaxy 23 million light-years away and was discovered by the eclipse of its star, a compact, ultra-powerful X-ray source.

A new method for searching for exoplanets, which is also suitable for studying other galaxies, is to register a decrease in the brightness of powerful X-ray sources (degenerate stars), which is caused by the transit of the planet. Thus, it was possible to detect the object M51-ULS-1b in the spiral galaxy M51 (the “Whirlpool” galaxy in the constellation of the Dog Hounds), which may be a gas giant or a brown dwarf in the X-ray binary system. An article by astronomers at the Harvard-Smithsonian Center for Astrophysics about this possible discovery appeared in September 2020 and is still available as a preprint at arXiv.org; it will probably be published later in the Monthly Notices of the Royal Astronomical Society (MNRAS).

The Whirlpool Galaxy, or M51, is a spiral galaxy 23 million light years distant. It is distinguishable through binoculars (apparent stellar magnitude about + 8ᵐ), and it is easy to find it in the northern sky near the extreme star of the Big Dipper bucket, although formally the site belongs to the neighboring constellation of Hounds.

It is one of the first extragalactic objects to be photographed in the middle of the 19th century. The galaxy has a companion – the neighboring dwarf galaxy NGC 5195, which it gradually eats, so a pair of galaxies looks spectacular in the pictures. It is assumed that the painting by Van Gogh “Starry Night” depicts this very object, which was then well known for publishing astronomical sketches in magazines.

The Maelstrom nebula (possibly) in a painting by Van Gogh (1889).

Extragalactic planets are objects in star systems or lonely planets outside our Galaxy. Most of the about 6,000 exoplanets discovered today orbit around stars at distances of up to hundreds of light years, that is, they belong to the nearest galactic environs. 

More distant stars, even within the Galaxy, are beyond the scope of studying their planetary systems. Moreover, this applies to objects in other galaxies at distances of millions of light years (for example, the distance to the center of our Galaxy is 25 thousand light years, and the nearest giant galaxy Andromeda is located at a distance of 2.5 million light years). Nevertheless, several extragalactic candidate planets are known. 

They were all discovered by the method of gravitational microlensing (distortion of the trajectory of light rays from a distant light source in the gravitational field of a star and its planetary system). 

This is an indirect method, and at extragalactic distances there is practically no possibility to independently confirm the discovery of an exoplanet by other means. Object M51-ULS-1b became the first extragalactic planet, which was discovered by the method of transit, standard for the study of “near” exoplanets – observations of periodic “eclipses” by the planet of its star in the process of moving in orbit. 

The transit method is one of two popular methods for exploring nearby exoplanets, along with the radial velocity method. Currently, the TESS space telescope is in orbit, the main task of which is to monitor several thousand of the nearest stars in the entire celestial sphere and search for their planets in this way (for more details about this NASA project, there is a separate article on our website). 

A similar problem was previously solved by the Kepler space telescope, which has already completed its work. The main difference between the two projects is that TESS monitors almost the entire sky sector-by-sector, exploring stars at distances of up to 100-200 light years, while Kepler focused on a small area, but captured stars at distances of up to 3 thousand light years (there is also note on the site). 

But extragalactic distances are orders of magnitude greater, and precise observations of the brightness of ordinary stars even in neighboring galaxies are not yet possible. 

Therefore, only superbright objects are suitable for research in other galaxies (not necessarily stars that are bright in the optical range). So far, these are X-ray sources, which are most often binary systems, where a compact object (black hole or neutron star) actively absorbs the matter of the companion star.

X-ray image of the galaxy M51 by the Chandra telescope and the position of the X-ray source M 51-ULS at the edge of the young star cluster in a detailed Hubble image. Di Stefano et al. (2020).


There can be up to several hundred such objects in galaxies. In the above Chandra image of M51 (left), they appear as bright dots. If the system contains a large exoplanet, then it can cause a short-term full or partial drop in the brightness of the source in the X-ray range, similar to the optical transit that telescopes can track.

 The very first exoplanets discovered in the mid-1990s in our Galaxy were also found near such exotic objects. Subsequently, when the number of exoplanets began to be measured in thousands, interest for obvious reasons shifted to planets in star systems similar to the Sun (or even better – in their “zones of potential habitability” and preferably closer, for example, near Proxima Centauri).

A group at the Harvard-Smithsonian Center for Astrophysics searched for transit events among 2,624 archived light curves for more than two hundred X-ray sources in spiral galaxies M51 , M101, and  M104, according to the Chandra orbiting telescope . 

Two other objects here are also familiar to astrolamists – these are the photogenic galaxies “Pinwheel” in Ursa Major (M101) and “Sombrero” in Virgo (M104), well oriented for observations in relation to us. One of the cases found is in good agreement with the light curve in the single transit model. It belongs to the X-ray source designated M51-ULS-1 – a young massive binary system closer to the outskirts of the galaxy M51. 

The object that caused the source to completely darken for 20-30 minutes could theoretically belong to several classes, including rocky or gas planets, as well as stars – white dwarfs or M-class stars (ordinary stars are red dwarfs). 

The properties of the light curve, according to the authors, exclude the “stellar” nature of this object, which received the “exoplanetary” designation M51-ULS-1b… It is assumed that it is slightly smaller than Saturn and may be a hot gas giant or a substellar object – a brown dwarf. It moves in an orbit of a large radius (according to estimates – tens of astronomical units) and at one time survived a supernova explosion in this binary system, which led to the formation of a compact X-ray object. 

The authors of the work suggest that the method can be used to search for exoplanets both in other galaxies and in the Milky Way, and its accuracy will increase with the quality of data from orbiting telescopes.

Whirlpool Galaxy M51 and companion by Hubble
Galaxies M51 (“Whirlpool”) and NGC 5195 – image from the Hubble telescope . NASA / ESA / STScI .

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