AKARI's view on birth and death of stars

August 28, 2006
AKARI’s view on birth and death of stars
This view provides a comparison between a visible image (left) of the reflection nebula IC 1396 – an intense star forming region - and a mid-infrared view of the same area as seen by AKARI’s satellite (right). In the visible light (left image) it is possible to see the emission from ionized (charged) hydrogen gas as well as light emitted from the massive stars in the centre and scattered by the interstellar dust. High density gas clumps are seen as dark stains. New stars born in these dark regions do however appear bright if observed in infrared light (right image). Massive young stars, recently born in the centre of the imaged area (right image), blow out interstellar gas and dust and create the giant hollow seen in the central region. The gas that has been swept out creates the bright filament-like structures seen in the infrared in the surrounding regions. The dust in the gas is heated by the intense light coming from both the massive star at the centre of the nebula and the newly born stars in the dense gas itself, and emits infrared light. The bright clump seen on the slightly off-centre right-hand side is known as the ‘Elephant Trunk Nebula’, a star forming region too. It appears as a dark nebula in the visible light (left image), but it is very bright in the infrared. It is a clump of dense gas that was not originally blown away because of its very high density. Credits: D.De Martin, ESA/ESO/NASA FITS Liberator & Digitized Sky Survey (left), JAXA (right)

AKARI, the Japan Aerospace Exploration Agency (JAXA) infrared astronomical satellite with ESA participation, is continuing its survey of the sky and its mapping of our cosmos in infrared light. New exciting images recently taken by AKARI depict scenes from the birth and death of stars.

AKARI's Infrared Camera (IRC) imaged the reflection nebula IC 1396 in the constellation Cepheus (a reflection nebula is a cloud of dust which reflects the light of nearby stars). IC 1396 is a bright star-forming region located about 3000 light years from our Solar System, in a region where very massive stars – several tens of times as massive as our Sun - are presently being born. Massive young stars in the central region of the image have swept out the gas and dust to the periphery of the nebula, creating a hollow shell-like structure.

A new generation of stars is now taking place within the compressed gas in these outer shell structures. With this high-resolution and high-quality image of IC 1396, AKARI has revealed for the first time the detailed distribution of the gas and dust swept out over the entire nebula.

A comparison between a visible image of IC 1396 and AKARI's view of the same area shows that stars being born in regions that appear dark in visible light (left), do however appear bright if observed in infrared light (right).

The gas that has been swept out creates the bright filament-like structures seen in infrared in the surrounding regions. The dust in the gas is heated by the intense light coming from both the massive star at the centre of the nebula and the newly born stars in the dense gas itself, and emits infrared light.

AKARI’s view on birth and death of stars
This far-infrared image (90 micrometers wavelength) shows the red giant star ‘U Hydrae’ as viewed by AKARI’s Far-Infrared Surveyor (FIS) instrument. This star is located at about 500 light years from our Sun. AKARI’s observations have revealed very extended clouds of dust surrounding this star. Stars with masses close to that of our Sun will expand during the later stages of their life becoming so-called ‘red-giant’ stars. During the final phase of their life such stars often eject gas from their surface into interstellar space - dust is formed in the ejected gas, and this mixture of gas and dust expands and escapes from the star. AKARI's superior quality and high-resolution imaging allowed the clear detection of a shell-like dust cloud surrounding U Hydrae at a distance of about 0.3 light years from the central star. This implies that a short and violent ejection of mass took place in the star about 10 000 years ago. Credits: JAXA

The bright clump seen on the slightly off-centre right-hand side is known as the 'Elephant Trunk Nebula', a star forming region too. It appears as a dark nebula in the visible light (left image), but it is very bright in the infrared. It is a clump of dense gas that was not originally blown away because of its very high density.

Many recently born stars that were previously unknown are now expected to be detected thanks to AKARI's new image, while the detailed analysis of these data will reveal the story of the star formation in this area.

AKARI's Far-Infrared Surveyor (FIS) instrument imaged the red giant 'U Hydrae', a star located at about 500 light years from our Sun. AKARI’s observations have revealed very extended clouds of dust surrounding this object.

Stars with masses close to that of our Sun will expand during the later stages of their life becoming so-called 'red-giant' stars. During the final phase of their life such stars often eject gas from their surface into interstellar space - dust is formed in the ejected gas, and this mixture of gas and dust expands and escapes from the star.

AKARI's superior quality and high-resolution imaging allowed the clear detection of a shell-like dust cloud surrounding U Hydrae at a distance of about 0.3 light years from the central star, implying that a short and violent ejection of mass took place in the star about 10 000 years ago.

Source: ESA

Explore further: Amateur astronomer helps uncover secrets of unique pulsar binary system

Related Stories

New dwarf satellite galaxy of Messier 83 found

December 5, 2016

(Phys.org)—Astronomers have found a new dwarf satellite of Messier 83 (M83, also known as the Southern Pinwheel Galaxy) located some 85,000 light years from its host. This satellite galaxy was designated dw1335-29 and could ...

How strong is the force of gravity on Earth?

December 7, 2016

Gravity is a pretty awesome fundamental force. If it wasn't for the Earth's comfortable 1 g, which causes objects to fall towards the Earth at a speed of 9.8 m/s², we'd all float off into space. And without it, all us terrestrial ...

Embryonic cluster galaxy immersed in giant cloud of cold gas

December 1, 2016

Astronomers studying a cluster of still-forming protogalaxies seen as they were more than 10 billion years ago have found that a giant galaxy in the center of the cluster is forming from a surprisingly-dense soup of molecular ...

Recommended for you

Scientists sweep stodgy stature from Saturn's C ring

December 9, 2016

As a cosmic dust magnet, Saturn's C ring gives away its youth. Once thought formed in an older, primordial era, the ring may be but a mere babe – less than 100 million years old, according to Cornell-led astronomers in ...

Japan launching 'space junk' collector

December 9, 2016

Japan will launch a cargo ship Friday bound for the International Space Station, carrying a 'space junk' collector that was made with the help of a fishnet company.

Dark matter may be smoother than expected

December 7, 2016

Analysis of a giant new galaxy survey, made with ESO's VLT Survey Telescope in Chile, suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought. An international team ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.