Cosmic science: Inclined planets around small stars can hardly survive life

There are many traits that can make a planet difficult to survive, a new study suggests: " For some planets, the tilting trajectory may be one of those factors. " .

Planets orbiting distant stars may be suitable conditions for survival if they are located in what is known as a " habitable " area - the area around the star where the planet is located. Sufficient sunlight to allow liquid water to exist on the surface. With this temperature is suitable for our life on Earth.

An impressive image of an artist capturing a rocky planet around the red dwarf Proxima Centauri - the star closest to the Sun.Photo source: ESO / M. Kornmesser

But a new study shows that for a planet orbiting a small and fuzzy star known as " M-dwarf star ", the planet's tilt may make it planetary form does not exist life, even if it is in the star's living area. The study examined the planet's " inclination " - or its inclination versus the flat disk of the orbit - affecting the change in temperature on the surface.

A tilted planet is the north pole that not only straightens its way around its stars, while the equator is aligned with its orbit. The planet with the largest tilt is its poles, which are tilted, sometimes too large, making them almost coincide with the planet's orbit.

" We found that in general, the planet's climate with a higher inclination is usually warmer than a planet with a lower incline. The inclined planet is always hotter than its sister planets, evaporating water from the surface is farther away than the host star, compared to the planet with a lower inclination. For these planets, the boundary within the habitable zone is moved outward and away from the stars , "the group said. International research, headed by Yuwei Wang of China's Beijing University, said in their article.

The change in the habitable region seems to sound reasonable, because it will move the planets that are farther away, radiation produced by M-dwarfs. However, planets with high inclination also freeze faster than planets with lower inclination, meaning that the boundary outside the area where life exists is also effective when diverting inside.

As a result, " planets with a higher inclination will have smaller survival areas ."

Narrow living areas

Scientists say that M-dwarfs are more than 10 times more popular than sun-like stars, seeming to be " good candidates " for searching for Earth's ability to live, planets. . Because they are faint, it is easy for scientists to discover planets around them. ( Attentively observing a bright star may lose any sign of a planet ). And especially the life time of a dwarf-M - simulated longer than 13.8 billion years of the universe - a very long life time to develop.

Although these stars are faint, they still emit a significant amount of radiation. Previous studies have shown that M-dwarfs continuously release plasma ( the fourth state of matter, other states are solid, liquid, gas, in which substances are strongly ionized ) and particles. charged with colliding the orbits of planets, causing danger to life on the surface. Scientists continue to discuss conditions on planets orbiting fuzzy stars that may be suitable for life.

Discover tilted planets

While most planetary studies around M-dwarfs focused on vertical planets, Wang's team decided to focus on their inclined brothers first. According to scientists, most studies suggest that the forces of gravity from M-dwarfs pull up planets in their lock-tide orbit, where one face faces permanently with stars. But the new study shows that the moon - locked the tide with the Earth even though the moon only tilted 6.7 degrees.

" It is entirely possible that Earth-like planets have life around M-dwarfs that maintain any inclination between 0 and 90 degrees, " Wang's team said.

To determine the effects that tilt rotation could have on the planet of life, the researchers made an atmospheric model similar to planets. On planets with a slope of 0, the star continuously shines through the equator, while the planets tilt 90 degrees, the star continuously shines on one pole. However, when a planet has a tilt of between 0 and 90 degrees, the star's path of movement changes throughout the year.

On Earth, where the inclination angle is 23.5 degrees, the sun's path in the sky creates seasons because the area with the strongest sunlight often changes throughout the year.

For M-dwarfs, the researchers found that the higher the inclination, the higher the temperature, and the planets are very close to the stars. Previous studies have shown that inclined planets orbiting a star like the sun, reducing ice on the surface, means that light is less reflected back into space, so the planet holds less heat.

" However, on dwarf-M-planetary planets, which are in very short years, hot spots are constantly moving, leading to reduced cloud formation ," new studies reveal. " Less cloud cover means less light and heat reflected into space, forming a hotter planet than a vertical planet with a similar orbit, " the researchers said.

" Ironically, mobile hotspots hold larger planets than" full "hot words on the outside. Because the hottest part of the planet is moving constantly, the planet has difficulty keeping up. It is warm and can freeze more easily, it will orbit a sun-like star , "the researchers said.

The new study was conducted on the outer boundary of the existence of the tilted planets located closer to the stars.

" For planets orbiting M-dwarfs, the inner edge of the living area pushes the stars further away, while the outer edge pushes closer inward ," Ravi Kopparapu , the extraterrestrial scientist , A researcher from NASA's Goddard Space Center in Greenbelt, Maryland, replied to Space.com by email. Kopparapu, who is not involved in the study, also studied planets in habitable areas around other stars.

" Therefore, the width of the living areas seems to be reduced ," Kopparapu said.

" The careful calculations of the study of the inner region of an inclined planet are about 5 percent smaller than a vertical planet. If the planet suffers from an uncontrolled greenhouse effect (runaway greenhouse effect) - when air enters the atmosphere leading to more gas production and therefore, generating more heat - the habitat may be reduced by more than 20 percent, "the new study says.

The study is published in the Astrophysical Journal Letters .

The regions are expected to have life in different types of stars, shown in blue around the stars.Different types of stars: A stars are big and hot stars (lying on top), the G stars are like the sun (in the middle) and the faint M stars (at the bottom).Photo source: NASA

Things to worry about

Planets form a cloud of gas and dust left over after their star is born. When many planets orbiting a star, they can interact as gravity of gravity can help a planet out of its original vertical position. Collisions can also alter the tilt of the planet. Scientists suspect that penetrating objects can orbit Venus and Mars on their axis.

Although scientists can calculate the inclination of planets in the solar system, measuring the tilt of other planets is a challenge. According to Kopparapu, " Measuring the light directly from the planet may reveal its tilt. However, current instruments do not have the sensitivity needed to perform these measurements. The glass Future prospects, such as the European Extremely Large Telescope (E-ELT) and Thirty Meter Telescope (TMT) can measure planetary tilt ". European giant telescope E-ELT is currently being built in the Atacama desert in Chile, the first light can be observed in 2024. The construction of a thirty-meter TMT telescope in Hawaii was blocked blocked by law violations ".

The return to the interior of habitable regions seems to be good news for dwarf-M-dwarf planets, meaning that water-containing planets have more dangerous radiation. However, Kopparapu thinks that the move may be too small to make a significant difference.

" I think these planets will not escape harmful radiation, even if the inner edges move a bit, this change will not be enough to compensate for the radiation blasts ," he said. .

" What the planet needs - whether it's high or low - is some kind of protective barrier, like the Earth's ozone layer, to prevent UV radiation ," he said.

" A thick atmosphere helps prevent most of the radiation from reaching the surfaces of the planet, giving the life of a better opportunity to grow. Because M-dwarfs work more than the sun and In areas near it, their planet needs a thicker atmosphere than Earth , "Kopparapu added.

" If life exists on the planet around M-dwarfs, there is a lot to worry about how to survive ," Kopparapu said.