gingadan.com

SN 1987A (Supernova Remnant)


Home > Black Hole > SN1987A
Down
Movie

SN 1987A
Supernova Remnant (超新星残骸)
SNR


星座 (Constellation)

かじき座 (Dor) (Dorado)


距離 (Distance)
163,000光年 (163,000 light-years)

SN 1987A すなわち1987年超新星A は、大マゼラン雲内に発見された超新星です。初めて観測されたのが1987年2月23日であり、これが同年最初に観測された超新星であることから 1987A という符号が付けられている。「SN」は「超新星」を意味する "supernova" の略です。地球からは16.4万光年離れているため、実際に超新星爆発が起こったのは16万年前のことである。23日午前10時30分(UT)に撮影された大マゼラン銀河の写真に写っており、可視光で捉えられたのはこれが最初とされる。超新星発見の報告が最初になされたのは24日のことである。超新星の明るさは5月にピークを迎え、視等級にして最大3等級となったあと、数ヵ月かけて徐々に減光した。肉眼で観測された超新星としてはSN 1604(ケプラーの超新星)以来であり、現代の天文学者にとっては初めて超新星を間近に観察する機会となった。

超新星が可視光で観測される3時間前の2月23日午前7時35分にこの超新星爆発に伴うニュートリノバーストが観測されている。ニュートリノを検出したのは日本のカミオカンデ、アメリカ合衆国オハイオ州にあるIMB、ロシアのBaksanの各ニュートリノ観測施設で、カミオカンデでは11個、IMBでは8個、Baksanでは5個のイベントが検出された。ニュートリノバーストは少なくとも13秒間続いた。超新星爆発の理論モデルでは爆発のエネルギーの大部分がニュートリノとして放出されるとされているが、この観測ではそれを裏付ける結果となった。また、モデルによるとこの超新星爆発で放出されたニュートリノは1058個、エネルギーにして1046ジュールにのぼると考えられているが、これも観測結果と一致する。
爆発によって生じたエネルギー量は、太陽が45億年かけて放出してきた全エネルギーの1000倍の量を僅か10秒で放出したものと推定される。

超新星爆発によるニュートリノが観測されたのは SN 1987A が初めてであり、ニュートリノ天文学の記念すべき第一歩と紹介されることがある。宇宙から飛来するニュートリノの観測例としては太陽ニュートリノの観測が1960年代から行われていたが、ニュートリノの飛来した方向、時刻、エネルギー分布が詳細に分析されたのはこの観測が初めてであり、ニュートリノ天文学を大きく飛躍させたという意味で重要な業績である。この成果によって東京大学名誉教授の小柴昌俊が2002年にノーベル物理学賞を受賞している。

SN 1987A の超新星爆発を起こした恒星はサンデュリーク-69° 202という質量が太陽の20倍ほどの青色超巨星であることが分かっている。また爆発後には超新星残骸として三重リング構造を持つ星雲状の天体が観測されている。

SN 1987A is a supernova remnant located 163,000 light years from the Earth in the constellation Dorado.

SN 1987A (Supernova Remnant) : Picture

SN 1987A (Supernova Remnant)
SN 1987A (Supernova Remnant)
(C) NASA, ESA, P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics)
Two decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years.

Since that first sighting, the doomed star, called Supernova 1987A, has continued to fascinate astronomers with its spectacular light show. NASA's Hubble Space Telescope is one of many observatories that has been monitoring the blast's aftermath.

This image shows the entire region around the supernova. The most prominent feature in the image is a ring with dozens of bright spots. A shock wave of material unleashed by the stellar blast is slamming into regions along the ring's inner regions, heating them up, and causing them to glow. The ring, about a light-year across, was probably shed by the star about 20,000 years before it exploded.

Astronomers detected the first bright spot in 1997, but now they see dozens of spots around the ring. Only Hubble can see the individual bright spots. In the next few years, the entire ring will be ablaze as it absorbs the full force of the crash. The glowing ring is expected to become bright enough to illuminate the star's surroundings, providing astronomers with new information on how the star expelled material before the explosion.

The pink object in the center of the ring is debris from the supernova blast. The glowing debris is being heated by radioactive elements, principally titanium 44, created in the explosion. The debris will continue to glow for many decades.

The origin of a pair of faint outer red rings, located above and below the doomed star, is a mystery. The two bright objects that look like car headlights are a pair of stars in the Large Magellanic Cloud. The supernova is located 163,000 light-years away in the Large Magellanic Cloud.

The image was taken in December 2006 with Hubble's Advanced Camera for Surveys.

Composite image of Supernova 1987A
Composite image of Supernova 1987A
(C) ESO
This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the centre of the remnant. Hubble (in green) and Chandra (in blue) data show where the expanding shock wave is colliding with a ring of material around the supernova. This ring was initially lit up by the ultraviolet flash from the original explosion, but over the past few years the ring material has brightened considerably as it collides with the expanding shockwave.

Artist's illustration of Supernova 1987A
Artist's illustration of Supernova 1987A
(C) ESO
This artist's illustration of Supernova 1987A is based on real data and reveals the cold, inner regions of the exploded star's remnants (in red) where tremendous amounts of dust were detected and imaged by ALMA. This inner region is contrasted with the outer ring (lacy white and blue circles), where the blast wave from the supernova is colliding with the envelope of gas ejected from the star prior to its powerful detonation. This ring was initially lit up by the ultraviolet flash from the original explosion, but over the past few years the ring material has brightened considerably as it collides with the expanding shockwave.

SN1987A
SN 1987A (Supernova Remnant)
(C) NASA

SN1987A SN1987A
SN 1987A (Supernova Remnant)
(C) NASA
SN 1987A (Supernova Remnant)
(C) NASA

Cosmic Rays and Supernova Dust
Cosmic Rays and Supernova Dust
(C) M. DeBord, R. Ramaty and B. Kozlovsky (GSFC), R. Lingenfelter (UCSD), NASA
Cosmic Rays are celestial high energy particles traveling at nearly the speed of light, which constantly bombard the Earth. Discovered during high altitude balloon flights in 1912 their source has been a long standing mystery. But a recent theory suggests that cosmic ray particles are atomic nuclei blasted from dust grains formed in supernovae, the death explosions of massive stars. This artist's illustration shows a supernova explosion (at left) and a conical section of the expanding cloud of ejected material. Atoms are torn from the brownish bands of "dust" material by shock waves (represented by orange rings). The shocks in the expanding blast wave then accelerate the atoms to near light speeds firing them into interstellar space like cosmic bullets. The theory is supported by observations indicating that high velocity dust was formed in the nearby supernova 1987A, and that Beryllium, a light element created in Cosmic Ray collisions, is found equally in both old an young stars. NASA's Advanced Composition Explorer (ACE) satellite can also test details of the theory by directly measuring Cosmic Rays.

Bright Knot Appears in Supernova 1987a Ring
Bright Knot Appears in Supernova 1987a Ring
(C) NASA
[RIGHT] - This NASA Hubble Space Telescope Wide Field and Planetary Camera 2 image shows the glowing gas ring around supernova 1987A, as it appeared in 1994. The gas, excited by light from the explosion, has been fading for a decade.

[LEFT] - Recent Hubble telescope observations show a brightening knot on the upper right side of the ring. This is the site of a powerful collision between an outward moving blast wave and the innermost parts of the circumstellar ring. The collision heats the gas and has caused it to brighten in recent months. This is likely to be the first sign of a dramatic and violent collision that will take place over the next few years, rejuvenating SN1987A as a powerful source of X-ray and radio emissions.

The white sickle-shaped material in the center is the visible part of the shredded star, rushing outward at 3,000 kilometers per second, which is heated by radioactive elements created in the supernova explosion.

The bright dot in the lower left is a star, which is the same direction as SN1987A, but is not physically part of the system.

Both images were made from separate images taken in blue light, visual light and the narrow emission from glowing hydrogen. Computer image processing techniques were used to enhance details in the ring.

Supernova 1987A Ring Blazes Back to Life
Supernova 1987A Ring Blazes Back to Life
(C) NASA
[Left]
This NASA Hubble Space Telescope Wide Field and Planetary Camera 2 image shows the glowing gas ring around supernova 1987A, as seen on February 2, 2000. The gas, excited by light from the explosion, has been fading for a decade, but parts of it are now being heated by the collision of an invisible shockwave from the supernova explosion.

[Right]
Image processing is used to emphasize four new bright knots of superheated gas discovered in the February 2 Hubble observations. The brightest knot, at the far right, was seen in 1997. Astronomers have been waiting several years to see more of the ring light-up as the supernova shockwave smashes into it. This is the first definitive sign of the full onset of a dramatic and violent collision which will continue over the next few years, rejuvenating SN1987A as a powerful source of X-ray and radio emissions.

Both images were made in visual light. Computer image processing techniques were used to enhance details in the ring.

Supernova 1987A in the Large Magellanic Cloud
Supernova 1987A in the Large Magellanic Cloud
(C) The Hubble Heritage Team (AURA/STScI/NASA)
Glittering stars and wisps of gas create a breathtaking backdrop for the self-destruction of a massive star, called supernova 1987A, in the Large Magellanic Cloud, a nearby galaxy. Astronomers in the Southern hemisphere witnessed the brilliant explosion of this star on Feb. 23, 1987.

SN 1987A (Supernova Remnant) SN 1987A (Supernova Remnant)
SN 1987A (Supernova Remnant)
(C) NASA/ESA
SN 1987A (Supernova Remnant)
(C) NASA/ESA
Supernova 1987A Debris Disk Mysterious Ring Structure around Supernova 1987A
Supernova 1987A Debris Disk
(C) NASA/ESA
Mysterious Ring Structure around Supernova 1987A
(C) NASA/ESA
Composite image of Supernova 1987A Supernova 1987A
Composite image of Supernova 1987A
(C) ESO
Artist's illustration of Supernova 1987A
(C) ESO
Up
Up

SN 1987A (Supernova Remnant) : Movie

Supernova 1987A
Up
Home > Black Hole > SN1987A
Up

「ウィキペディア(wikipedia):フリー百科事典」より文章引用。
SN 1987A. (2013, March 23). In Wikipedia.
gingadan.com ブログパーツ