On the third day, Hua Feng saw scientists from the Geneva Observatory in Switzerland announce at an academic conference held in France on June 16, 2008, that they had discovered five new "super-Earths". Of the five "super-Earths" discovered this time, three are located 42 light-years away from the Earth, in the direction of the constellation Atlas and the constellation Australopithe, which are 4.2 times more massive, 6.7 times and 9.4 times that of the Earth, respectively.

These three "super-Earths" orbit a star slightly smaller than the Sun with periods of 4, 10 and 20 days, respectively. The fourth "super-Earth" orbits the star HD181433 a period of 9.5 days. The stellar HD181433 also attracts a Jupiter-like planet with a three-year orbital period. The fifth "super-Earth" is 22 times the mass of the Earth and revolutions once every 4 days.

Since the discovery of the first "super-Earth" in 1995, astronomers have discovered more than 270 more planets, most of which are as large as Jupiter and Saturn, and few planets of similar size to Earth. Because most of the "super-Earths" are too far away from us, astronomers cannot directly observe them with the naked eye through ordinary astronomical telescopes, but can only rely on radio waves or spectral analysis and other detection methods to "indirectly calculate" the existence of "super-Earths".

On December 16, 2009, according to US media reports, an international research team composed of American and Australian scientists found that there are four terrestrial planets in the adjacent two sun-like star systems, two of which are called "super-Earths" after studying the observation data of the "Keck" telescope and the Anglo-Australian radio telescope.

Researchers believe that this discovery will provide important clues for mankind to find habitable planets, and the hope of discovering habitable planets will greatly increase in the next few years.

Of these four terrestrial planets, two of them are called "super-Earths", which are more massive than Earth but less massive than Uranus and Neptune. The existence of these "super-Earths" suggests that it is only a matter of time before a habitable planet similar to Earth is discovered.

Of the four newly discovered terrestrial planets, three of them are located on the star "61 Vi

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is" around. “61 Vi

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The star is the de facto twin brother of the Sun, located 28 light-years from Earth in the constellation Virgo. At this time of year, one can observe Virgo in the night sky hours before the sun rises. The researchers estimated the minimum possible mass of each of the three planets.

Chris Tinney, a member of the research team and an astronomer at the University of New South Wales in Australia, believes that "61 Vi

b "has a minimum mass of about 5.1 times the mass of the Earth," 61 Vi

c" is about 18 times the mass of the Earth, and "61 Vi

d" is about 23 times the mass of the Earth. According to Tinney, "the mass of the smallest of these planets is exactly within the mass range of super-Earths." This is the first time a planet of this size has been found around a sun-like star. "Previously, scientists had also

"Super-Earths" have been found around other stars, but those stars are much colder than the Sun.

On December 22, 2009, astronomers believe that the planet is closer to Earth than any exoplanet found outside the solar system.

BEIJING, Dec. 17, 2009 (Xinhua) -- Astronomers have discovered a terrestrial planet orbiting a faint star, just 40 light-years away from Earth, Sina Technology quoted the British Daily Mail as reporting that astronomers have discovered a dim star.

It is a steaming "water world" that is 6 times the size of the Earth. It is believed that 75% of the planet's surface area is covered by water, but it is too hot to support Earth-type life. There is evidence that this "water world" also has an atmosphere. Astronomers believe the planet is closer to Earth than any exoplanet previously discovered outside of our solar system.

By measuring the decrease in brightness caused by the passage of a planet, scientists are able to calculate the density of a planet and make educated guesses about its composition. The newly discovered planet was named "GJ1214b" and is believed to be covered in water and ice in three-quarters of the surface, leaving only about a quarter of the area left for rock.

Harvard-Smithsonian Center graduate student and astronomer Chuckry Berta discovered the hydroplanet. "Despite the high temperatures, it's still a world with water," he said. Compared to any other known exoplanet, this planet is smaller, cooler and closer to Earth. ”

Scientists believe that something other than the surface of GJ1214b must block light from the parent star, which may be surrounded by an atmosphere made of hydrogen and helium. With the help of the Hubble Space Telescope, astronomers may be able to determine the composition of the planet.

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David Chabonneo, head of OJECT, said: "Due to the planet's very close proximity to Earth, 'Hubble' should be able to probe the atmosphere and determine its composition. If you're lucky, it will be the first super-Earth to have a proven atmosphere, though that atmosphere may not be friendly to life as we know it. ”

The discovery was reported in the journal Nature on the 16th. In an article published in Nature, renowned planet hunter Professor Jeffrey Marcy of the University of California in the United States speculates about what this water world might look like. "It may have an extremely deep ocean and should be liquid," he wrote. Due to the heat imparted by the parent star, its surface temperature reaches around 190 degrees Celsius. In addition, a sauna-like vapor atmosphere may also be present. ”

Extrasolar planets. It works on the principle of "occultation" – when one or more planets pass in front of their parent star, the star's light is partially blocked, and its brightness decreases slightly. With unprecedented precision metering from the Kepler telescope, it is able to detect this change in brightness and reverse the presence of occultations, or planets.

After analyzing data from the Kepler telescope over the past seven months, a team of scientists from Harvard's Smithsonian Center for Astrophysics has discovered two planetary targets orbiting a star numbered Kepler-9. The star is located about 2,300 light-years from Earth.

One of these planets, Kepler-9b, orbits its parent star for only 19 days. The other, Kepler-9C, takes 39 days to revolutionize a week.

The researchers found that the orbits of the two planets have periodic changes in speed and slowness. This means that the two planets are caught in "gravitational resonance" – their gravitational pull interacts with each other, which in turn affects the characteristics of their respective orbits. Using this data, the researchers were able to calculate the mass of the two planets. Calculations show that both planets are gas giants slightly heavier than Saturn.

But when the researchers tried to explain the loss of brightness of the central parent star in terms of the size of the two planets, they were surprised to find another faint occultation. This faint signal detected indicates the presence of a smaller planet with orbits closer to the parent star in the system. Its orbital orbital period is 1.6 days. The planet has a mass equivalent to about 1.5 Earths and is a terrestrial planet made of rock.

But the researchers can't celebrate this yet, because there are many interference factors for such a weak signal. Background stars or companion stars in binary systems produce similar signal effects.

"So far, all we can say is that we've found a very interesting signal, and we're hopeful that we'll have more information soon," said Matt Holma

said. He was the chief scientist for the study. But even if this signal turns out to be a terrestrial planet, humans are unlikely to want to settle there: the planet's surface temperature is about 1,900 degrees Celsius, based on its orbital position [4]. On September 29, 2010, astronomers from the National Science Foundation announced on September 29, 2010 that they had discovered a planet that is most similar to Earth to date, with parts of it in an environment and temperature suitable for human habitation.

The planet, Gliese 581g, is located in the constellation Sagittarius and orbits the red star Gliese 581, which is much smaller than the Sun. The star is located 20 light-years from Earth, and astronomers have found six planets orbiting Gliese 581. The other 5 (Gliese 581b to Gliese 581f) are not located in the "Goldilocks zo."

e" (habitable area), however, this one is right in the habitable zone, and its temperature is not too hot or too cold, so that liquid water can form oceans, lakes and rivers.

Gliese 581g is likely to be a rocky planet with a surface of water and atmosphere, about 1.2 to 1.4 times the diameter of the Earth, about 3.1 to 4.3 times the mass of the Earth, and a gravitational pull similar to that of the Earth, with an average surface temperature of between minus 31 and minus 12 degrees.

The red dwarf star orbiting around it is only 1/50 the temperature of the Sun and 1/3 of the Sun's volume. Gliese 581g orbits its "sun" for only 37 days, and it is always facing the "sun" on one side and in darkness on the other. Therefore, the sunny side of it can be very hot, the temperature can reach more than 100 degrees, and the temperature of the backlit side can be tens of degrees below zero.

The most appropriate location for human beings of life or future is the "gray" zone, the transition zone of darkness and light in Gliese 581g. Depending on its longitude, many life forms can find stable climatic environments suitable for their emergence and evolution.

Astronomers have found nearly 500 planets outside our solar system, but almost all of them are too large, made of gas rather than rock, and the temperatures are either too hot or too cold for life as we know it. Penn State astronomer Justin said, "This is the first planet that really thrilled me. He thinks the planet is perfect for life.