Wabbu released the first picture of the exterior planet to find another earth to find another earth!(Down)

In the previous part, we introduced the four most important methods of the outer planet "Zoo" and the detection department.

Next, we started to introduce the detailed nature of the HIP 65426b shot by the James Webb SPACE Telescope (hereinafter referred to as "Weibu"). The exciting prospect of the earth.

3. Webu's camera object -HIP 65426B

The system composed of HIP 65426 and its planet HIP 65426B is located in the direction of a half -person horse. In the most sensitive V -band of the human eye, HIP 65426 is a 7 -class star, which cannot be seen by human eye, because the limit of the stars with the naked eye is 6 or 6.5. That's why we can only use the telescope to see it.

According to the GAIA satellite measurement in 2020, HIP 65426 is about 350.6 light years from Earth. The temperature on the surface is about 8840 k, which is slightly higher than the surface temperature of the sun (5772 k). Its mass is about 1.96 times the quality of the solar. Its radius is about 1.77 times the radius of the sun. Its age is about 14 million years, which is far lower than the age of the sun (about 4.6 billion years).

HIP 65426B around HIP 65426 takes 631 years (referring to the year on the earth, the same below). In comparison, one week from the farthest planet Neptune to the sun is 164.8 years, and the dwarf planet underworld has a turnover of 247.94 years.

HIP 65426 Star Map, it is located in the center of the yellow circle, two stars (half -man horses, Rigil Kent) and horse belly (halfman horse seat β star, hadar) at the center of the yellow circle

After the HIP 65426 B was discovered by VLT-3, before Webb shot it, astronomers have studied its nature through various means. These studies show that (1) HIP 65426 B is very "young" and age is about 14 million years. In contrast, the earth is more "mature", about 4.6 billion years. (2) HIP 65426 B's atmosphere is high, lack of carbon, rich in oxygen, and carbon dioxide, but methane and ammonia are not detected. (3) The surface temperature of HIP 65426 B is about 1560 K. (4) The quality of HIP 65426 B is about 10 or 11 times the quality of Jupiter.

According to the theory of planet formation, when the gas and dust around the stars are gradually condensed into the planet, there will be some remnant disk substances around. To the puzzlement of astronomers, HIP 65426 B is still so young, but the surrounding disk has disappeared. This is contradictory with the current popular theoretical model.

The shooting of Weibu in the infrared band (above 3 microns) is conducive to people to understand the nature of the planet more thoroughly. The Aarynn L. Carter of the Department of Astronomy and Celestial Physics of the University of California Cruz presided over the study. They used Wabbu to take 7 bands (see the figure below. In order to make the small map more beautiful, the team only announced the image of 4 of the bands to the media, see the first picture of the previous article).

The image of HIP 65426B taken by Webb. The 7 small pictures were filmed by the average wavelength of 2.523 microns, 3.067 microns, 3.580 microns, 4.084 microns, 4.397 microns, 11.307 microns and 15.514 microns. The white five -pointed star indicates the position of the star, and the light emitted by the star itself is blocked by the star coronation. Image source: a. Carter et al. Arxiv: 2208.14990v2

In the images taken, the angle distance between HIP 65426 and HIP 65426B is about 0.82 cents. Combined with the distance between them and the earth, Carter and others calculate the average track radius of the HIP 65426B of about 87 astronomical units (1 celestial unit equal to 150 million. A kilometer, the average distance between the earth and the sun), is about three times the average rail radius of Neptune and twice the average rail radius of Pluto.

Carter et al. Put the data obtained by Weibu with the data from the previous Sphere, which gets the brightness value within the range of 1 to 16 micron. The brightness within the wavelength range accounts for 97%of the total brightness of the HIP 65426 B.

Carter et al. Draw these data into diagrams (see the figure below).

In the figure, the seven bands obtained by Webu are represented by an orange hollow point; Sphere's integral field spectrometer (IFS) obtained near -infrared spectrum is expressed by dense black hollow triangles; Sphere's infrared difference is obtained by the infrared differential imaging instrument and spectrometer (Irdis) (Irdis). The metering point is represented by black hollow cubes; NASMYTH adaptive optical system-CONICA near-infrared camera (NACO) obtained by NASMYTH self-adaptive optical system on VLT-1 is represented by black hollow diamonds.

Figure: HIP 65426B's near-infrared spectrum (hollow point on the left dense triangle), near infrared-medium infrared test data (other hollow dots, of which the orange empty dot is data observed by Weibu), the best model fitting line (blue The optimal values ​​(blue solid small dots) obtained in some bands (blue solid small dots) and the model of the model indicate the scope of the error range. Figure below: Residuals in each band, that is, the value obtained after the observation data minus the theoretical value. Image source: A. Carter et al. Arxiv: 2208.14990v2 is obvious. Weibu supplemented with metering data of more than 5 microns, and its measurement value of about 4 microns and the value of NACO of VLT have the difference in the naked eye. Essence Carter et al. Fit the data with atmospheric models (they did not include NACO data when fitting because they contradicting the data obtained by Webu).

Model fitting indicates that the temperature of HIP 65426 B is about 1673 k; the radius of HIP 65426 B is about 0.92 times the radius of Jupiter. Carter and others also combine the observation results with the evolutionary model. The obtained radius of the planet is about 1.45 times the radius of Jupiter, and the surface temperature obtained is about 1282 k. On this basis, the thermal brightness of the HIP 65426 B calculated by Carter et al. The thermal brightness of 45 times to 6.2 times of 100,000 to 100,000 of the sun thermal brightness, and then its quality is about 7.1 times the quality of Jupiter (the error is the quality of the Jupiter's quality 1.1 times).

The result of Carter et al. This result has 3 times the accuracy of some of the previous physical quantities.

Fourth, Weibu's performance test

In the near -infrared band and medium infrared band, the light of the mother star reflected by the HIP 65426 B is only one -ten or thousands of light of its mother star. Webb used the star's corona to block the light of the star and took this photo. From an intuitive point of view, the picture taken by Webbu is not as clear as VLT-3, but Webu shoots a longer-wavelength medium-infrared image.

Because the temperature of the outer planet is much lower than the star, a considerable part of the radiation in the infrared band is radiated. Important properties such as temperature and radius (see the above section). On this basis, people can also more accurately determine the thermal brightness and quality of the external planet.

In addition, compared to the ground telescope, the Webu shooting department has the following advantages: the telescope observation on the ground is disturbed by the atmosphere, so it is often necessary to use "adaptive optical" technology to eliminate the impact of the atmosphere; Weibu is in space, and It is not disturbed by the atmosphere, so it does not require the assistance of this technology, which allows it to obtain more accurate measurement data.

VLT-4 ("Yepun", which means "Venus") is laser, creating laser guide stars to perform the "adaptive optical" program to eliminate the impact of atmosphere on observation. Image source: G. Hüdepohl/ESO

Carter and others believe that Webb's successful shooting shows that it has 10 times the abilities of the external planet in the shooting department.

Fifth, let our "dim blue dot" no longer alone

As early as 1584, Girldano Bruno (1548-1600) speculated that those stars in the sky might have planets around them. However, it was not until 1992 that human beings discovered the outer planet for the first time. At this time, it had been more than 400 years since Bruno raised this guess.

From then on, humans have developed a variety of high -precision technologies, and have discovered more than 5,000 exogenous planets and at least 8,000 candidates to be confirmed. These technologies are not only the crystallization of human mind, but also the unremitting efforts of humans when looking for the same kind of the earth.

Through this shooting, Webb proved its excellent performance in observing foreign planets, making it officially an important member of the study of foreign planet.

Weibu's observation in the infrared band is particularly important for the important numerical values ​​such as the temperature, radius, thermal brightness, and quality of the external planet. In addition, the keen spectrometer it carries allows people to more accurately infer the atmospheric and surface chemical composition of some planets in the "livable belt" of the mother star, so that humans can further determine whether they are suitable for life survival. And evolution. In the end, Web also has the advantages of large -caliber, high sensitivity, and high accuracy.

The combination of these advantages has made Weiban have special advantages in determining the nature of the external planet and finding another "earth".

Outer planets ("Livable Planets") confirmed by astronomers may be suitable for life survival and evolution. The distance and name are given below each planet, and "LY" represents light years. From top to bottom from top to bottom, the Earth, Mars, Jupiter and Neptune from the top to bottom. Photo source: phl @ upr Arecibo (pHL.upr.edu)

On February 14, 1990, Voyager No. 1 (Voyager 1), who had been flying in space for more than 12 years, took a precious photo of 6 billion,000,000,000 thousands of meters from the earth. In this picture, the tiny highlight with only 0.12 pixels and seemingly insignificant is the earth, and it is almost drowned by the color light formed by the camera's reflection of the sun. Traveler No. 1 is shot in the earth 6 billion kilometers away from the earth, and it is just a very small source of pictures in the picture: NASA

In 1994, the famous astronomer and popular science writer Carl Sagan (1934-1996) referred to the point in the figure as "Pale Blue Dot", and used it as the name of a book. Blue dots are our precious home.

When we stare at the dim blue dots in the photo, we can't help asking: "Is our earth really lonely in the universe?" Some possible livable planets that humans have gradually discovered can make us more and more Optimisticly give this question a negative answer.

Although the various properties of these possible livable planets still have a gap with our earth, we can optimize expectations: with the help of Weibu and other powerful telescopes, humans will quickly find the nature closer to our earth, The livable planet that is more suitable for life survival and evolution, until the real other earth is found, so that our dim blue dot is no longer so lonely.

Egg: Questions and Answers

Question: How to directly determine the approximate value of the average wavelength of the radiation in the image according to the number at the bottom right of the photo posted?

Answer: Divide the numbers in it directly with 100, and then micron as a unit. The difference between the value obtained and the real average wavelength can be ignored. Try to the above picture of 7 small pictures, and compare the wavelength given below the picture.

Produced: Popular Science China

Author: Wang Shanqin

Producer: China Science Popularization Expo

The China Science Popularization Expo is the Science Popular Science Platform of the Chinese Academy of Sciences. It is sponsored by the Computer Network Information Center of the Chinese Academy of Sciences. Relying on the high -end scientific resources of the Chinese Academy of Sciences, it is committed to spreading cutting -edge scientific knowledge and providing fun science and education services.

- END -