gingadan.com

Homunculus Nebula (Eta Carinae)


Home > Solar System > Homunculus Nebula
Down
Movie

Homunculus Nebula (人形星雲)
Eta Carinae (りゅうこつ座イータ星)

Luminous Blue Variable, LBV (高輝度青色変光星)

別名 (Other names)
HD 93308, IRAS 10431-5925, りゅうこつ座η星

星座 (Constellation)
りゅうこつ座 (Car) (Carina)

距離 (Distance)
7,500光年 (7,500 light-years)

Homunculus Nebula (Eta Carinae) is a luminous blue variable located 7,500 light years from the Earth in the constellation Carina.

Homunculus Nebula (Eta Carinae) : Picture

Eta Carinae (Luminous Blue Variable)
Eta Carinae (Luminous Blue Variable)
(C) NASA/ESA/Hubble
At the turn of the 19th century, the binary star system Eta Carinae was faint and undistinguished. In the first decades of the century, it became brighter and brighter, until, by April 1843, it was the second brightest star in the sky, outshone only by Sirius (which is almost a thousand times closer to Earth). In the years that followed, it gradually dimmed again and by the 20th century was totally invisible to the naked eye.

The star has continued to vary in brightness ever since, and while it is once again visible to the naked eye on a dark night, it has never again come close to its peak of 1843.

The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.

Although 19th century astronomers did not have telescopes powerful enough to see the 1843 outburst in detail, its effects can be studied today. The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its launch in 1990. This image, taken with the Advanced Camera for Surveys High Resolution Channel is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.

Eta Carinae is not only interesting because of its past, but also because of its future. It is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future (though in astronomical timescales the “near future” could still be a million years away). When it does, expect an impressive view from Earth, far brighter still than its last outburst: SN 2006gy, the brightest supernova ever observed, came from a star of the same type.

Homunculus Nebula
3D Homunculus Nebula
Science Credit: W. Steffen (UNAM), M. Teodoro, T.I. Madura, J.H. Groh, T.R. Gull, A. Mehner, M.F. Corcoran, A. Damineli, K. Hamaguchi Image Credit: NASA, Goddard Space Flight Center/SVS - Inset: NASA, ESA, Hubble SM4 ERO Team
If you're looking for something to print with that new 3D printer, try out a copy of the Homunculus Nebula. The dusty, bipolar cosmic cloud is around 1 light-year across but is slightly scaled down for printing to about 1/4 light-nanosecond or 80 millimeters. The full scale Homunculus surrounds Eta Carinae, famously unstable massive stars in a binary system embedded in the extensive Carina Nebula about 7,500 light-years distant. Between 1838 and 1845, Eta Carinae underwent the Great Eruption becoming the second brightest star in planet Earth's night sky and ejecting the Homunculus Nebula. The new 3D model of the still expanding Homunculus was created by exploring the nebula with the European Southern Observatory's VLT/X-Shooter. That instrument is capable of mapping the velocity of molecular hydrogen gas through the nebula's dust at a fine resolution. It reveals trenches, divots and protrusions, even in the dust obscured regions that face away from Earth. Eta Carinae itself still undergoes violent outbursts, a candidate to explode in a spectacular supernova in the next few million years.

Eta Carinae (Luminous Blue Variable)
Eta Carinae (Luminous Blue Variable)
(C) Nathan Smith (University of California, Berkeley), and NASA

Eta Carinae (Luminous Blue Variable)
Eta Carinae (Luminous Blue Variable)
(C) ESO

Eta Carinae (Luminous Blue Variable)
Eta Carinae (Luminous Blue Variable)
(C) J. Hester/Arizona state University & NASA Hubble Space Telescope

Eta Carinae Eta Carinae
Eta Carinae (Luminous Blue Variable)
(C) NASA/ESA/Hubble
Eta Carinae (Luminous Blue Variable)
(C) Nathan Smith, NASA
Eta Carinae Eta Carinae
Eta Carinae (Luminous Blue Variable)
(C) ESO
Eta Carinae (Luminous Blue Variable)
(C) J. Hester/Arizona state University/NASA
Up
Up

Homunculus Nebula (Eta Carinae) : Movie

NASA | Scientists Create First Full 3D Model of Eta Carinae Nebula
An international team of astronomers has developed a 3D model of a giant cloud ejected by the massive binary system Eta Carinae during its 19th century outburst. Eta Carinae lies about 7,500 light-years away in the southern constellation of Carina and is one of the most massive binary systems astronomers can study in detail. The smaller star is about 30 times the mass of the sun and may be as much as a million times more luminous. The primary star contains about 90 solar masses and emits 5 million times the sun's energy output. Both stars are fated to end their lives in spectacular supernova explosions.

Between 1838 and 1845, Eta Carinae underwent a period of unusual variability during which it briefly outshone Canopus, normally the second-brightest star. As a part of this event, which astronomers call the Great Eruption, a gaseous shell containing at least 10 and perhaps as much as 40 times the sun's mass was shot into space. This material forms a twin-lobed dust-filled cloud known as the Homunculus Nebula, which is now about a light-year long and continues to expand at more than 1.3 million mph (2.1 million km/h).

Using the European Southern Observatory's Very Large Telescope and its X-Shooter spectrograph, the team imaged near-infrared, visible and ultraviolet wavelengths along 92 separate swaths across the nebula, making the most complete spectral map to date. The researchers have used the spatial and velocity information provided by this data to create the first high-resolution 3D model of the Homunculus Nebula.

The shape model was developed using only a single emission line of near-infrared light emitted by molecular hydrogen gas. The characteristic 2.12-micron light shifts in wavelength slightly depending on the speed and direction of the expanding gas, allowing the team to probe even dust-obscured portions of the Homunculus that face away from Earth.

Carina Nebula in 60 Seconds
Up
Home > Solar System > Homunculus Nebula
Up

gingadan.com ブログパーツ