* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> Stars/galaxy News -> Carina Nebula dust pillars
Post Info TOPIC: Carina Nebula dust pillars
Blobrana


L

Posts: 131433
Date:
Eta Carinae
Permalink  
 

Title: The Chrysalis Opens? Photometry from the Eta Carinae HST Treasury Project, 2002-2006
Authors: J.C. Martin, Kris Davidson, M.D. Koppelman

During the past decade Eta Car has brightened markedly, possibly indicating a change of state. Here we summarize photometry gathered by the Hubble Space Telescope as part of the HST Treasury Project on this object. Our data include STIS/CCD acquisition images, ACS/HRC images in four filters, and synthetic photometry in flux-calibrated STIS spectra. The HST's spatial resolution allows us to examine the central star separate from the bright circumstellar ejecta. Its apparent brightness continued to increase briskly during 2002--06, especially after the mid-2003 spectroscopic event. If this trend continues, the central star will soon become brighter than its ejecta, quite different from the state that existed only a few years ago. One precedent may be the rapid change observed in 1938--1953. We conjecture that the star's mass-loss rate has been decreasing throughout the past century.

Read more (128kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Title: Submillimetre Emission from Eta Carinae
Authors: H. L. Gomez (nee Morgan), L. Dunne, S. A. Eales, M. G. Edmunds

Researchers present critical, long-wavelength observations of Eta Carinae in the submillimetre using SCUBA on the JCMT at 850 and 450 um to confirm the presence of a large mass of warm dust around the central star. They fit a two-component blackbody to the IR-submillimetre spectral energy distribution and estimate between 0.3-0.7 solar masses of dust exists in the nebula depending on the dust absorption properties and the extent of contamination from free-free emission at the SCUBA wavelengths. These results provide further evidence that Eta Carinae's circumstellar nebula contains > 10 solar masses of gas, although this may have been ejected on a longer timescale than previously thought.

Read more (293kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Title: A hot transient jet from eta Carinae
Authors: Ehud Behar, Raanan Nordon, Eyal Ben-Bassat, Noam Soker (Technion)

Eta Carinae is a stellar binary system with a period of 5.54 years. It harbours one of the brightest and most massive stars in our galaxy. This paper presents spectroscopic evidence for a fast (up to 2,000 km/s) X-ray jet of ionised gas launched from Eta Carinae just before what is believed to be the binary periastron (point of smallest binary separation). By analogy with jets in other astrophysical systems, it is possible to attribute the jet to the onset of a phase of accretion.

Read more (127kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
Keyhole Nebula
Permalink  
 

This close-up view of area surrounding the dusty Keyhole Nebula (NGC 3324).
The Great Carina Nebula (NGC 3372) is a star-forming region that is 7,500 light-years away in the southern sky. The image spans about 40 light-years within the larger Carina Nebula.


Expand (692kb, 1570 x 1156)

The false colours are derived from three exposures through narrow filters each intended to record the light emitted by specific atoms in the gaseous nebula. Sulphur is shown in blue, hydrogen in green and oxygen in red hues. The Carina Nebula is home to young, extremely massive stars, including the variable star Eta Carinae. Highlighted by diffraction spikes, Eta is just above and right (east) of the Keyhole.
South is toward the top.

__________________
Blobrana


L

Posts: 131433
Date:
Eta Carinae
Permalink  
 

Eta Carinae is a massive star, but it's not as bright as it used to be. Now only easily visible in binoculars or a small telescope, Eta Carinae has a history of spectacular flaring and fading behaviour.
In April of 1843 Eta Car briefly became second only to Sirius as the brightest star in planet Earth's night sky, even though at a distance of about 7,500 light-years, it is about 800 times farther away. Surrounded by a complex and evolving nebula, Eta Carinae is seen near the centre of this false-colour infrared image, constructed using data from the Midcourse Space Experiment (MSX).
The MSX satellite mapped the galactic plane in 1996.


Expand ( 103kb, 897 x 897)
Credit: MSX, IPAC, NASA

In the picture, wispy, convoluted filaments are clouds of dust glowing at infrared wavelengths. Astronomers hypothesize that Eta Car itself will explode as a supernova in the next million years or so.
Massive Eta Car has even been considered a candidate for a hypernova explosion and the potential source of a future gamma-ray burst.


__________________
Blobrana


L

Posts: 131433
Date:
RE: Trumpler 14
Permalink  
 

Energetic winds from the stars have cleared out a cavity in the dense cloud, filling it with shock heated, x-ray emitting gas.


Expand

Over the next few million years these stars will rapidly exhaust their nuclear fuel and explode in violent supernovae, flooding their cosmic neighbourhood with gas enriched in heavy elements.

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

A Chandra x-ray telescopic view of the star cluster Trumpler 14 shows about 1,600 stars and a diffuse glow from hot multimillion degree X-ray producing gas. The cluster has one of the highest concentrations of massive, luminous stars in the Galaxy. Located 9,000 light years away on the edge of a giant molecular cloud, it is part of the Carina Complex which contains at least 8 star clusters.

The bright stars in Trumpler 14 are about 1 million years old, and much more massive than the Sun. They will shine brightly, exhaust their prodigious energy, and explode spectacularly as supernovas in a few million years.


Expand (184kb, 567 x 672)
Position(2000): RA 10h 43m 57.50s Dec -59° 32' 53.00"
Credit: NASA/CXC/PSU/L.Townsley et al.

In the meantime, the young, massive stars have a profound influence on their environment through the ionizing effects of their light, and the high-speed winds of particles that are pushed away from their surfaces by the intense radiation. Shock waves that develop in these winds can heat gas to millions of degrees Celsius and produce intense X-ray sources. In the accompanying image (below, right), the bright white source in the centre of the wide-field image has been resolved to reveal several massive stars.
On a larger scale, stellar winds can carve out cavities in the clouds of gas and dust that surround the stars, and trigger the formation of new stars. These cavities are filled with million-degree gas that produces the diffuse X-ray glow in the image.

The glow in the lower, rectangular part of the image (the gap between the upper and lower portions of the image is an instrumental artefact) is from a gas cloud that has been enriched with oxygen, neon, silicon and iron. This probably marks the final contribution of a once-bright star that exploded as a supernova thousands of years ago, and in the process dispersed these heavy elements into the interstellar medium.

source

__________________
Blobrana


L

Posts: 131433
Date:
Carina Nebula dust pillars
Permalink  
 

Carina Nebula dust pillars harbour embedded stars.
Astronomers using NASA's Spitzer Space Telescope have imaged a giant molecular cloud being shredded by howling stellar winds and searing radiation, exposing a group of towering dust pillars harbouring infant stars, according to a University of Colorado at Boulder researcher.
Nathan Smith, a Hubble Fellow and postdoctoral researcher at CU-Boulder's Centre for Astrophysics and Space Astronomy, said the violent panorama is unfolding in the Carina Nebula, located in the southern Milky Way some 10,000 light years from Earth.
The orbiting infrared telescope imaged a new generation of stars in various stages of evolution, several dozen of which now gleam like gems at the heads of huge dust pillars created by the galactic weather conditions.


Position (J2000): RA: 10:45:03.591 Dec: -59:41:04.26

"Spitzer is providing us with the first snapshot of a molecular cloud being shredded on such a large scale. Stellar winds and blowtorch-like radiation coming off the massive stars are ripping apart the cloud, exposing a new generation of stars at the ends of these pillars." - Nathan Smith.
Smith presented the results of the NASA-funded study at the 206th meeting of the American Astronomical Society held May 29 to June 2 in Minneapolis, US.

"One of the motivations for our observations is that our own sun probably formed in a violent region like the one we are seeing in the Carina Nebula," - Nathan Smith.
Located in the southern Milky Way galaxy, the Carina Nebula is visible to the human eye and contains the variable star Eta Carina, which puts out more energy than 1 million suns and which is expected to explode into a supernova in the coming millennia. Stellar winds whipping from Eta Carina and several dozen other massive stars in the region blow at 2,000 kilometres a second, or more than 4 million miles per hour.
"There is a fierce contest going on. On one hand we have these massive, first-generation stars trying to remove all of this gaseous material, and the young stars like those embedded in the dust pillars are trying to accrete the material to build themselves up." - Nathan Smith.

Launched in 2003, the heat-seeking Spitzer Space Telescope is an ideal observatory to study the wild activity in the Carina Nebula. The orbiting telescope's infrared array camera penetrates regions like Carina filled with dense clouds of gas and dust, allowing astronomers to witness star formation processes that are shrouded from the view of other types of telescopes.

The study also included the University of Wisconsin-Madison's Ed Churchwell, Brian Babler and Marilyn Meade, Barbara Whitney of the Space Science Institute in Boulder, Vanderbilt University's Keivan Stassun, Arizona State University's Jon Morse and the University of Minnesota's Robert Gehrz. The Spitzer Space Telescope is managed for NASA by the Jet Propulsion Laboratory in Pasadena and science operations for the effort are conducted at the Spitzer Science Centre at the California Institute of Technology in Pasadena.

Smith and his colleagues combined several hundred images obtained by scanning the South Pillar region of the nebula with Spitzer in spring 2005 to produce the mosaic. Using four different camera filters, the team detected more than 17,000 stars, including those forming at the pillar heads.

"We looked only at the most active region, but there are probably many more stars embedded in pillars in the surrounding area".
The researchers believe Eta Carina was the primary player that shaped the gigantic dust pillars. Before 1840 - when the star shed the equivalent of 10 solar masses of material from its outer layer - it is thought to have been the most luminous UV light source in the nebula. For several years after the 1840 event, Eta Carina was the second brightest star in the sky.
Sculpted from reservoirs of gas and dust by the whipping stellar winds and high-energy radiation, the dust pillars "point back" toward the luminous Eta Carina.

"All of the different pillars were exposed to the same light bulb."

The Carina Nebula has a diameter of about 200 light years, and the dust pillars are up to 10 light years, or 50 trillion miles, in length, said Smith. The Carina Nebula is about 100 times more luminous than the much closer Orion Nebula and may contain as many as 100,000 young stars, most of which are faint, low mass stars like the sun.

Medium-Resolution (900x720): JPEG (272 KB)
High-Resolution (3000x2400): JPEG (7 MB)


Source

__________________
«First  <  1 2 3 | Page of 3  sorted by
 
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> Stars/galaxy News -> Carina Nebula dust pillars


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard