Research press release


Nature Physics

Star caught on camera hours after public explosion



2013年10月6日に、完全に自動化された掃天サーベイであるIntermediate Palomar Transient Factory(iPTF)によって、NGC 7610と呼ばれる近傍銀河である事象が捉えられた。発見されてから程なくして、さまざまな望遠鏡を用いてこの事象が観測された。O Yaronたちは今回、集めた情報を解析して、何が起こったか見いだした。彼らは、この事象が、赤色超巨星が爆発したII型超新星であったことを示している。さらに、爆発前の約1年間に作られた物質円盤がこの星を取り囲んでいたことを示す証拠も見いだした。この星は、生涯最後の日々に大量の物質を急速に放出し、崩壊前に質量を失ったのである。II型超新星は最もよく見られる超新星なので、Yaronたちの観測結果は、爆発する星の一般的シナリオを示唆している。

The first observation of the very early stages of a supernova, only three hours after the explosion and early enough to spot the debris and determine what happened just before the destruction, is reported in a paper published online this week in Nature Physics.

Supernovae are spectacular astrophysical explosions that mark the death of massive stars. Witnessing the very early stages of a supernova can provide a glimpse into the star's environment prior to the explosion and insights into how and why stars end their lives in such a dramatic way, but such events are extremely rare.

On 6 October 2013, the Intermediate Palomar Transient Factory (iPTF), a fully automated survey of the sky, spotted an event in a nearby galaxy called NGC 7610. Shortly after the event’s discovery, different telescopes were used to observe it, and Ofer Yaron and colleagues analysed the gathered information to find out what had happened. They show that the event was a red supergiant exploding into a type II supernova. They also found evidence that the star was encircled by a disk of matter that had been created in the year before its explosion. In its final days, the star had been rapidly ejecting lots of material, losing mass before the collapse. As type II are the most common form of supernovae, the observations made by Yaron and colleagues suggest a general scenario for exploding stars.

doi: 10.1038/nphys4025


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