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Astrophysicists have studied the diversity of exoplanets and their relationship Astrophysicists have studied the diversity of exoplanets and their relationship

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Astrophysicists have studied the diversity of exoplanets and their relationship with the metallicity of the stellar environment

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A team of astrophysicists conducted a study to more fully understand the processes of planet formation in low-metallicity stellar environments. According to previous research, the formation of dust particles large enough to form rocky planets requires a gradual growth from micrometer size to planetesimal size. However, the mechanisms associated with this process in low metallicity environments remain poorly understood.

Astrophysicists have studied the diversity of exoplanets and their relationship with the metallicity of the stellar environment

Illustration of planetesimal formation

For their study, astrophysicists conducted a global simulation of the evolution of a viscous disk. They took into account the growth of dust grains, evaporation and condensation of chemicals on snow lines. The researchers also examined different levels of metallicity, disk sizes, and the strength of turbulent viscosity.

As a result of the study, it was found that at solar and subsolar metallicity* there is a significant increase in the mass ratio of dust and gas in the middle plane near the snow lines, but this leads to the formation of planetesimals only near the water ice line. At metallicity [Fe/H] = -0.6 (the value -0.6 indicates that in this case the amount of iron is slightly less than in the Sun), the formation of several Earth-mass planetesimals is possible.

It turns out that under the extreme conditions of protoplanetary disks, larger disks are preferable to small ones for the formation of large numbers of planetesimals with a fixed metallicity, since pebbles can persist for longer periods of time, leading to more efficient formation of planetesimals.

At lower metallicity, there is less support for planetesimal formation in quiescent disks compared to turbulent disks, since pebbles can be supported for longer periods of time. In simulations, it was found that the number of planetesimals formed at subsolar metallicity limits the size of the core, which can only lead to the formation of super-Earths.

“Subsolar metallicity” is a term used to describe a level of metallicity comparable to that of the Sun. The level of metallicity is measured in comparison to the concentration of iron (Fe) in the Sun. If the metallicity value is 0 (zero metallicity), then this means that the amount of metals in the star is the same as in the Sun.

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Car News

Hyundai Creta N Line 2024 sports car declassified

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Hyundai Creta N Line 2024 sports car declassified

The sportiest version of the recently updated Hyundai Creta crossover has been declassified in India: orders for the Hyundai Creta N Line 2024 in the local market are already being accepted, but the official premiere will take place on March 11.

Hyundai Creta N Line 2024 sports car declassified

Judging by the photo, the crossover received more aggressive bumpers, a different radiator grille, and red accents on the body and interior design. Wheels will be 18 inches. According to Autocar India, the car will be offered in two trim levels: base and top-end. Accordingly, the first will have a manual gearbox, the second will have a robotic one. But there is only one engine – the most powerful: a 1.5-liter gasoline turbo engine with 160 hp.

Hyundai Creta N Line 2024 sports car declassified

Hyundai Creta N Line 2024 sports car declassified

Prices will be announced on the day of the premiere, but it is already clear that the Creta N Line will be the most expensive in the lineup.

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How much does it cost to repair Xiaomi 14 Ultra? The official price list for spare parts has been published

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How much does it cost to repair Xiaomi 14 Ultra

Xiaomi 14 Ultra has just gone on sale in China, but Xiaomi has already published the official price list for spare parts so that users understand how much it will cost to repair the device out of warranty.

How much does it cost to repair Xiaomi 14 Ultra?  The official price list for spare parts has been published

Despite the fact that Xiaomi 14 Ultra is currently the pinnacle of the Chinese company’s smartphone manufacturing, repair prices are approximately at the level of other flagships. Replacing the motherboard will cost the most – from 380 to 420 dollars, depending on the amount of memory soldered on it. Out-of-warranty replacement of the screen will cost $190, battery – $25, back cover – $40. Replacing the front camera is $10, speaker replacement is $5.

As for the camera, this is interesting. Replacing the main module with an inch Sony LYT-900 image sensor will cost $140! Replacement of a module with an ultra-wide-angle lens is $70, replacement of a module with a telephoto lens is only $25. And this is quite strange, since these modules use the same Sony IMX858 sensors, and the module with a telephoto lens is more complex due to the presence of an OIS system.

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Components

A mini PC weighing only 660 grams with an 8-core Ryzen 7 7840HS, 32 GB of RAM, a built-in screen and a fingerprint scanner – for $515. Tianbao GEM12 introduced

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A mini PC weighing only 660 grams with an 8 core

An atypical mini-computer went on sale on the Chinese marketplace JD.com. The creators of the device, called Tianbao GEM12, integrated a small screen and even a fingerprint scanner into the body, which can work as part of the Windows Hello biometric identification function.

A mini PC weighing only 660 grams with an 8-core Ryzen 7 7840HS, 32 GB of RAM, a built-in screen and a fingerprint scanner - for $515.  Tianbao GEM12 introduced

The hardware basis of Tianbao GEM12 is an 8-core 16-thread Ryzen 7 7840HS processor with a Radeon 780M graphics core. The device is sold as a DIY kit for $350 or as a pre-configured system: 16GB/512GB for $430 and 32GB/1TB for $515.

A mini PC weighing only 660 grams with an 8-core Ryzen 7 7840HS, 32 GB of RAM, a built-in screen and a fingerprint scanner - for $515.  Tianbao GEM12 introduced

A mini PC weighing only 660 grams with an 8-core Ryzen 7 7840HS, 32 GB of RAM, a built-in screen and a fingerprint scanner - for $515.  Tianbao GEM12 introduced

The mini-PC cooling system has two heat pipes and one fan. The screen is used to display the time, album covers when playing music, and processor load. There is an integrated 2.5 Gbps wired Ethernet adapter with two RJ-45 ports and a module that implements Wi-Fi 6 and Bluetooth 5.2 communications.

A mini PC weighing only 660 grams with an 8-core Ryzen 7 7840HS, 32 GB of RAM, a built-in screen and a fingerprint scanner - for $515.  Tianbao GEM12 introduced

Dimensions of the computer: 130 x 130 x 60 mm, weight: 660 grams.

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