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An ultralight source of x-rays detected, coming from the Draco constellation

ESA / Hubble

Intriguing ultralight source of X-rays, one of the brightest ever seen. It comes from a galaxy of the Draco constellation.

The ultraluminous X sources were discovered in 1980 with the Einstein space detector. The X-rays currently detected come from a galaxy located 14.8 million light years from Earth. This type of radiation has been quite mysterious to astronomers because it is extremely bright.

These astronomical systems ULEX, for its acronym in English, UltraLuminous X-ray source, have a brightness level of more than 10 raised to 39 erg per second (Ergis are units of measure of energy). The galaxy is called UGC 6456, and, interestingly, it is found in the constellation Draco (Dragon), a constellation object of legends and mythology.

X-ray source, UGC 6456 ULX

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Ultra-light X-ray sources. Credit: NASA

The study was conducted by Russian astronomers. These electromagnetic emissions are less luminous than a galactic core, but shine more than any process of formation or evolution of stars.

The group of astronomers is led by Alexander Vinokurov, from the Special Astrophysical Observatory, located in Nizhnij Arkhyz, Russia. The study presented says:

We present preliminary results of a study of the ultra-bright X-ray source UGC 6456 ULX. (…) To identify an optical counterpart of UGC 6456 ULX, we use archive images of the Chandra X-Ray Observatory and HST.

Note: HST stands for the Hubble Space Telescope.

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Overlay of images B, V and Rc of the UGC 6456 galaxy. The box shows the HST WFPC2 / F555W image of the region around the UGC 6456 ULX source, marked by the square; the circle indicates the 0.8 inch error box, derived from the Chandra Observatory data. Credit: Vinokurov et al.

The UGC 6456 galaxy is listed as a compact blue dwarf galaxy and is one of the closest to our Milky Way. Its UGC 6456 ULX source, or ultralight X-ray source, has mysterious properties, which they had not been studied in detail.

Among the brightest ever observed

The emissions of UGC 6456 ULX have brightness changes of more than two orders of magnitude with a maximum value of 17 erg duodecillions per second in the energy range of 0.3–8 keV (electron volts).

A duodecillón is a very long numerical scale equivalent to a 10 followed by 72 zeros! An electron volt is a unit of measurement that represents the energy per motion that an electron experiences.

Map of the constellation Draco "width =" 451 "height =" 500 "srcset ="
Map of the constellation Draco. Credit: Torsten Bronger / Wikimedia commons.

The magnitude of this source in its bright state is exceeded by an amount of -7.6. That makes her one of the ultraluminous sources of X-rays brightest ever discovered in the optical range.

The study presents a correlation between X-ray flows and optical (observable) flows in UGC 6456 ULX. This could indicate that the emission of optical light is produced by the X-ray re-processing in the outer parts of the so-called «Optically thick wind».

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Illustration of the phenomenon. Credit: NASA

The detection of many hydrogen and helium emission lines could relate to the wind that emerges from the powerful and dynamic accretion disk. This disk is a structure full of powder and cosmic gas that forms around a central object.

More details are expected with the following observations of this ultra-light source of X-rays. The light and energy changes of this system are similar to that of another known source, the so-called NGC 7793 P13, which has a neutron star.

The scientific study has been published on the pre-print website arXiv.org.

References: phys.org.

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Space

It’s a good start: TESS orbiting telescope discovers the first habitable world, with oceans

The TESS Space Telescope has discovered a planet on which oceans may exist. In addition, the exoplanet revolves around a quiet star, and this compares favorably with other candidates for the title of the cradle of extraterrestrial life. This is the first, but certainly not the last potentially inhabited world discovered by the TESS Observatory.

The space telescope was launched in 2018. Its task is to search for exoplanets, including those similar to Earth.

TESS has discovered 17 Earth-like planets orbiting 11 stars so far, according to a press release for the new study. All these luminaries are red dwarfs, which are smaller and colder than the Sun.

The TESS team divided almost the entire sky into sectors, each of which is observed for 27 days. However, these areas partially overlap, so some luminaries remain in the field of view of the device for much longer.

The TOI-700 star (aka TIC 150428135) is one of those “lucky ones”. Thanks to this, astronomers have discovered as many as three exoplanets about the size of the Earth.

The first of them (TOI-700b) has a radius almost equal to that of the Earth and revolves around its sun in 10 Earth days. The next planet, TOI-700c, is much larger than its neighbor (2.7 times the Earth’s radius). It makes a complete revolution in 16 days.

However, the most interesting of all is the third exoplanet from the planet TOI-700d. Its radius is 1.1 terrestrial, and its orbital period is 37 terrestrial days. It is this orbit around the cool local sun that makes the TOI-700d “right to life.” 

According to scientists, the planet receives 86% of the heat that goes to the Earth. This means that the temperature on this celestial body allows for the existence of liquid water and, therefore, the biosphere. According to experts, the exoplanet is in the habitable zone.

Planetary system TOI-700. The habitable zone is shown in green. One astronomical unit (AU) is equal to the distance from the Earth to the Sun. Illustration by Rodriguez et al. / Astronomical Journal (2020).

Three scientific articles published in the Astronomical Journal are devoted to the newly discovered world.

The first describes the discovery of this planet using the TESS telescope.

The second publication is devoted to the observation of an exoplanet using the Spitzer space infrared observatory. The telescope received this data in October 2019 and January 2020, shortly before the termination of its mission.

Finally, the authors of the third research paper simulated the possible climate of TOI-700d.

The researchers examined two dozen scenarios that differ from each other in the composition of the planet’s atmosphere, the amount of water on it, and other characteristics. Their conclusion is optimistic: a climate suitable for life is obtained in a fairly wide range of conditions.

It is important that TOI-700, unlike most other red dwarfs, is a calm star, not prone to catastrophic flares. That is, TOI-700d has every chance of preserving the atmosphere and hydrosphere for billions of years.

Of course, not without a fly in the ointment. TOI-700 is more than a hundred light years from Earth. It’s too far away to directly study the atmosphere of a small planet like TOI-700d, even with the future James Webb telescope .

However, the capabilities of astronomical instruments are growing rapidly. Perhaps in a few decades, scientists will carefully study the mysterious exoplanet and (who knows?) will find signs of the existence of life on it.

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Space

Apophis: A dangerous phenomenon was noticed on an asteroid threatening Earth

The asteroid Apophis, potentially dangerous for the Earth, experiences the Yarkovsky effect, as a result of which it gains acceleration and shifts to more and more threatening orbits with a collision with the Earth.

The asteroid Apophis, 325 meters in size, was discovered in 2004. The discovery caused a stir – calculations showed that there is a 2.7 percent probability that Apophis, named after the ancient Egyptian god of evil and destruction, will collide with the Earth in 2029. Then scientists ruled out this threat, calculating that on April 13, 2029, the asteroid will fly at a distance of 37.6 thousand kilometers from the center of the Earth.

The report on the detected displacement was presented at the Planetological Section of the Virtual Meeting of the American Astronomical Society in 2020 by a specialist from the Institute of Astronomy, University of Hawaii, Dave Tholen. According to the speaker and his colleagues, the asteroid Apophis is strongly susceptible to the Yarkovsky effect, which consists in a weak force effect on an object moving in space due to the inhomogeneity of thermal radiation.

All asteroids emit in the form of heat the energy of the sunlight they absorb in order to remain in a state of thermal equilibrium – and as a result of this process, the asteroid’s orbit changes weakly. Until now, it was believed that collisions of the asteroid Apophis during its approach to Earth in 2029 and 2068 are impossible. Taking into account the Yarkovsky effect with respect to a 325-meter potentially dangerous asteroid means that the scenario of its collision with the Earth in 2068 is updated again.

Apophis is the most likely candidate for a collision from the aton asteroids passing near the Earth, was discovered in 2004 and received its own name on July 19, 2005 in honor of the ancient Egyptian god Apop (Apophis) – a huge destroyer snake living in the darkness of the underworld and trying to destroy Sun (Ra).

During its approach to Earth on Friday, April 13, 2029, this asteroid will be visible to the naked eye as it passes within the orbits of Earth’s communications satellites.

One of the discoverers of Apophis, David Jay Tolen, in particular, said:

“We already know that the collision of this cosmic stone with our planet is impossible during the approach of 2029. However, the quality of our new observations with the Subaru telescope was high enough to reveal the acceleration resulting from the Yarkovsky effect on this asteroid.

Calculations have shown that the asteroid is annually displaced from a “purely gravitational” orbit by about 170 meters, and this displacement is enough to return the scenario of a collision with the Earth in 2068 among the probable outcomes .”

There are a number of services on Earth that track the potentially dangerous approaches of our planet with asteroids, but significant in body size, such as Apophis, attract the attention of scientists.

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Space

US professor said that the space expansion of earthlings will lead to the spread of totalitarianism

Political scientist Daniel Dodney believes that the foundation for future space conflicts is being laid on Earth today.

Space exploration is one of the main priorities for humanity in the 21st century. But not everyone agrees that the exit of our civilization beyond the boundaries of the globe will do more good than harm. For example, Daniel Dodney, professor of political science at Johns Hopkins University in the United States, believes that we should not attempt space expansion at all.

Dewdney is confident that the emergence of new habitats for people, in addition to the Earth, will lead to the emergence of interplanetary totalitarian empires. And if mankind somehow manages to master at least a few planets of the solar system, then nuclear weapons will become the “gold standard” in all wars (which, according to the professor, will not stop).

Although many colleagues consider Daniel’s arguments too pessimistic, the political scientist himself generally believes that people should abandon the exploration of outer space and search for a new home. 

“The large-scale expansion of human activity into space <…> must be included in the growing list of catastrophic existential threats to humanity,” Dodni insists.

No matter how gloomy the views of the American political scientist may look, they have certain grounds. So, in 2019, the United States announced the creation of a new type of its Armed Forces – space: they are “designed to protect the interests of the United States in space, deter aggression at long distances and conduct operational and consistent space operations.”

Daniel Dodney / The Brown Daily Herald
Daniel Dodney / The Brown Daily Herald

Other countries followed the American example: France, Canada and Japan announced their intentions to create similar troops. According to Dodnya, all this testifies to laying the foundation for future “near-earth conflicts.” According to his forecasts, space special forces will one day be able to control asteroids and comets to destroy settlements on rival planets or change the climate there, causing total extinction.

At the same time, the political scientist notes that he has nothing against “using space in ways that will benefit the Earth.” However, he doubts that this is possible.

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