This rare star, scientists have found nine at one time!

Author | Lamost Operation and Development Center

Recently, based on the resolution spectrum in LAMOST, scientists have discovered the unswatable stars with extremely high levels of lithium element content at one time, that is, Superford Lithium Dwarf. Among them, the lithium element content of one ultra -rich lithium dwarf reaches 31 times (4.8 DEX) of the sun. This discovery refreshes the record of the lithium element content of such stars and becomes the "lithium king" of the dwarf.

Prior to this, astronomers only found four similar ultra -rich lithium dwarfs. What is the resolution spectrum in LAMOST, and why can it achieve such high display results? Can this discovery reveal the relationship between the origin and evolution mechanism of lithium in the dwarf of the ultra -rich lithium?

01

There are also tall stars?

Before we figure out what is a super -wealth lithium dwarf, we need to understand what is a dwarf, as well as superstars. Stars, like humans, will experience the different stages of birth, growth, aging to death. The volume and temperature of the stages of the stars will change at different stages of the life course. The young and middle -aged stars at the stable main preface stage are called dwarfs. At this time, the stars have not yet begun to evolve.

After the hydrogen nucleus in the center of the star is extinguished, the stars will gradually evolve from the main sequence stage to a red superstar. What continues to maintain the vitality of the red superstar is burning at the hydrogen shell layer outside the nucleus. Name "superstar". After that, the red superstar will continue to evolve into the red cluster stars and the gradual bride stars in the later years. These stars in these evolutionary stages are called "superstars".

Taking the sun we are familiar with as an example, the sun is currently a yellow dwarf that has not yet evolved. When it evolves to the red superstar, the volume will become about one million times larger.

The solar show of the yellow dwarf star that has not evolved 丨 Picture Source: Veer Gallery

02

Where is the resolution spectrum god in Lamost?

Four thousand optical fiber swept the sky and explores the universe by millions of spectrums. LAMOST is a new type of optical astronomical telescope developed by scientists independently innovatively developed and has a number of international first -caliber and large -caliber. It is also my country's first astronomical national major scientific and technological infrastructure. Over the past ten years, Lamost has led the development of the international large -scale spectrometer project. It is the world's first sky -to -alarm weapon to launch spectral data over 10 million.

Guo Shoujing Wangyuan Mirror 丨 Picture Source: Science and Technology Daily

From September 2012 to June 2017, Lamost successfully completed the first low -resolution spectrometer task. In October 2018, Lamost officially opened the second -phase spectrum tour of the medium and low -resolution alternation. It is expected to end in June 2023. The so -called low -resolution celestial patrol is to obtain basic identity information of celestial bodies, while medium -resolution celestial patrol is in addition to obtaining basic identity information of celestial bodies, and can also obtain detailed chemical DNA information, which can better understand the origin and evolution of celestial bodies. Essence

In recent years, astronomers have made full use of the absolute advantages of resolution spectral data in Lamost, and have made breakthroughs in the research in cutting -edge science in the field of rare celestial bodies, star physics and dual stars evolution and nature.

03

Lithium element is the key element of the universe secret

Lithium is a key element that connects the Big Bang, interstellar material and stars. It has always been an important issue in the astronomical field in the universe and stars.

Earlier, astronomers found that there were extremely high lithium content in a very small number of stars that had evolved, which was a lithium -rich superstar. In the past few years, Lamost has achieved a series of breakthrough progress in the research of lithium -rich superstar, and has discovered more than 10,000 lithium -rich superstars, which deepened humans' awareness of the evolution of lithium elements in such rare celestial bodies and superstars. The existence of lithium -rich superstar shows that unknown mechanisms in the process of star evolution can significantly change the lithium content on the surface of the star.

However, the nine peculiar ultra -rich lithium dwarf stars in the research results show that not only superstars, very few dwarf stars that have not evolved have also shown that the lithium content is extremely high. It is at least three times higher than the lithium content in the sun, which means that these stars may be formed in an environment with higher lithium content near the sun, or it may be a special mechanism to increase the lithium content on the surface of the star.

04

Ultra -rich lithium dwarf that has not yet evolved into a superstar

This kind of super -wealthy dwarf star that has not yet evolved to the superstar stage is very rare. In the past, astronomers only found four, so they knew very little about their formation mechanisms. The formation mechanism of super -rich lithium dwarfs that has not yet evolved to superstar has always been controversial. Astronomers believe that atoms diffuse, stars accumulate the surrounding lithium -rich substances or stars in the double star system, interacting with the companion stars, interaction with the companion star The phenomenon that causes abnormal lithium element content may be a factor that forms a super -rich lithium dwarf.

This time, the researchers gave full play to the resolution spectrum tourism advantage in Lamost's multi -target, and discovered nine new super -rich lithium dwarfs at one time. In the research process, the research team comprehensively considered the effects of various factors on the content of lithium element, and combined with the Lamost spectrum and the timing metering data of the American TESS space telescope. Both are more than 9 kilometers per second, which is equivalent to 20 times the velocity of the Earth's autobiography. The brightness of three of which has periodic changes, and one is in the double star system. 9 newly discovered super -rich lithium dwarfs of the lithium element content schematic diagram 丨 Picture source: Yan Tai Sheng

These observation evidence shows that for most super -rich lithium dwarfs, accumulating lithium -rich substances may be the main mechanism for their abnormally increased lithium content, but it does not rule out that a few are the result of the interaction between double stars.

The thesis link:

https://iopScience.iop.org/article/10.3847/2041-8213/ac63a5

Produced: Popular Science China

Producer: China Science Popularization Expo

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