地震！ ガイア宇宙船は、これまでの最も詳細な天の川の調査で奇妙な星を見ています

Gaia 3のデータリリースから得られた驚くべき発見の1つは、Gaiaが星の形を変える恒星の地震（星の表面の小さな動き）を検出できることです。これは、天文台が本来は構築されていなかったものです。 クレジット：ESA / Gaia / DPAC、 CC BY-SA 3.0 IGO

ガイアは、欧州宇宙機関（ESA）の使命であり、10億を超える星の正確な3Dマップを作成します。[{” attribute=””>Milky Way galaxy and beyond. Although it launched all the way back in 2013, it is still working to accurately map the the motions, luminosity, temperature and composition of the stars in our galaxy.

Along the way it has made numerous discoveries, such as detecting a shake in the Milky Way, the observation of almost 500 explosions in galaxy cores, crystallization in white dwarfs, and discovering a billion-year-old river of stars. It also revealed the total weight of the Milky Way, a direct measurement of the galactic bar in the Milky Way, mysterious fossil spiral arms in the Milky Way, and a new member of the Milky Way family.

Today marks the data of the third data release from Gaia. The first data release was on September 14, 2016, followed by the second data release on April 25, 2018. On December 3, 2020, they did an early third data release with detailed data on more than 1.8 billion stars. All this data is helping to reveal the origin, structure, and evolutionary history of our galaxy.

This image shows four sky maps made with the new ESA Gaia data released on June 13, 2022. Credit: © ESA/Gaia/DPAC; CC BY-SA 3.0 IGO

Today (June 13, 2022), ESA’s Gaia mission releases its new treasure trove of data about our home galaxy. Astronomers describe strange ‘starquakes’, stellar DNA, asymmetric motions, and other fascinating insights in this most detailed Milky Way survey to date.

Gaia is ESA’s mission to create the most accurate and complete multi-dimensional map of the Milky Way. This allows astronomers to reconstruct our home galaxy’s structure and past evolution over billions of years, and to better understand the lifecycle of stars and our place in the Universe.

データバージョン3の新機能

Gaia 3のデータリリースには、私たちの銀河にある20億個近くの星の新しく改良された詳細が含まれています。 カタログには、以下を含む新しい情報が含まれています 化学組成恒星の温度、色、質量、年齢、および星が私たちに近づいたり遠ざかったりする速度（視線速度）。 この情報の多くは、新しくリリースされたものによって明らかにされました 分光法 データ、星の光をその構成要素の色（虹など）に分割する技術。 データには、時間の経過とともに明るさが変化する星など、星の特別なサブセットも含まれています。

また、このデータセットの新機能は、バイナリスター、小惑星や惑星衛星などの数千の太陽系オブジェクト、天の川の外にある数百万の銀河やクエーサーのこれまでで最大のカタログです。

地震

新しいデータから浮かび上がった最も驚くべき発見の1つは、ガイアが恒星の形を変える恒星の地震（星の表面の小さな動き）を検出できることです。これは、天文台が本来は構築されていなかったものです。

以前、ガイアは、球形を維持しながら、星が周期的に膨張および収縮する放射状の振動をすでに発見していました。 しかし、ガヤは現在、大規模な津波によく似た他の振動も検出しています。 これらの非放射状の振動は、星の全体的な形を変えるため、検出が困難です。

ガイアは、何千もの星で強い非放射状の地震を発見しました。 ガイアはまた、これまでほとんど見られなかった星のそのような振動を検出しました。 ガイアがそれらの表面でそれらを検出した間、これらの星は現在の理論によればいかなる地震も持たないはずです。

「スタークエイクは、スター、特にその内部の仕組みについて多くのことを教えてくれます。ガイアは、大規模な恒星科学のための金鉱を開きます」と、ガヤコラボレーションのメンバーであるベルギーのKUルーベンのコニーアーツは言います。

恒星のDNA

星が作られている材料は、星が生まれた場所と次の旅について、したがって天の川の歴史について教えてくれます。 今日のデータのリリースで、ガイアは私たちの太陽の近くから私たちの周りのより小さな銀河まで、3D運動と結合した銀河の最大の化学地図を明らかにします。

一部の星には、他の星よりも多くの「重金属」が含まれています。 間に[{” attribute=””>Big Bang, only light elements were formed (hydrogen and helium). All other heavier elements – called metals by astronomers – are built inside stars. When stars die, they release these metals into the gas and dust between the stars called the interstellar medium, out of which new stars form. Active star formation and death will lead to an environment that is richer in metals. Therefore, a star’s chemical composition is a bit like its DNA, giving us crucial information about its origin.

This image shows an artistic impression of the Milky Way, and on top of that an overlay showing the location and densities of a young star sample from Gaia’s data release 3 (in yellow-green). The “you are here” sign points towards the Sun. Credit: © ESA/Gaia/DPAC; CC BY-SA 3.0 IGO

With Gaia, we see that some stars in our galaxy are made of primordial material, while others like our Sun are made of matter enriched by previous generations of stars. Stars that are closer to the center and plane of our galaxy are richer in metals than stars at larger distances. Gaia also identified stars that originally came from different galaxies than our own, based on their chemical composition.

“Our galaxy is a beautiful melting pot of stars,” says Alejandra Recio-Blanco of the Observatoire de la Côte d’Azur in France, who is a member of the Gaia collaboration.

“This diversity is extremely important, because it tells us the story of our galaxy’s formation. It reveals the processes of migration within our galaxy and accretion from external galaxies. It also clearly shows that our Sun, and we, all belong to an ever-changing system, formed thanks to the assembly of stars and gas of different origins.”

This image shows the orbits of the more than 150,000 asteroids in Gaia’s data release 3, from the inner parts of the Solar System to the Trojan asteroids at the distance of Jupiter, with different color codes. The yellow circle at the center represents the Sun. Blue represents the inner part of the Solar System, where the Near Earth Asteroids, Mars crossers, and terrestrial planets are. The Main Belt, between Mars and Jupiter, is green. Jupiter trojans are red. Credit: © ESA/Gaia/DPAC; CC BY-SA 3.0 IGO, Acknowledgements: P. Tanga (Observatoire de la Côte d’Azur)

Binary stars, asteroids, quasars, and more

Other papers that are published today reflect the breadth and depth of Gaia’s discovery potential. A new binary star catalog presents the mass and evolution of more than 800 thousand binary systems, while a new asteroid survey comprising 156 thousand rocky bodies is digging deeper into the origin of our Solar System. Gaia is also revealing information about 10 million variable stars, mysterious macro-molecules between stars, as well as quasars and galaxies beyond our own cosmic neighborhood.

The position of each asteroid at 12:00 CEST on June 13, 2022, is plotted. Each asteroid is a segment representing its motion over 10 days. Inner bodies move faster around the Sun (yellow circle at the center). Blue represents the inner part of the Solar System, where the Near Earth Asteroids, Mars crossers, and terrestrial planets are. The Main Belt, between Mars and Jupiter, is green. The two orange ‘clouds’ correspond to the Trojan asteroids of Jupiter. Credit: © ESA/Gaia/DPAC; CC BY-SA 3.0 IGO, Acknowledgements: P. Tanga (Observatoire de la Côte d’Azur)

“Unlike other missions that target specific objects, Gaia is a survey mission. This means that while surveying the entire sky with billions of stars multiple times, Gaia is bound to make discoveries that other more dedicated missions would miss. This is one of its strengths, and we can’t wait for the astronomy community to dive into our new data to find out even more about our galaxy and its surroundings than we could’ve imagined,” says Timo Prusti, Project Scientist for Gaia at ESA.