Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers Bring The Third Dimension To A Doomed Star's Outburst

09.07.2014

In the middle of the 19th century, the massive binary system Eta Carinae underwent an eruption that ejected at least 10 times the sun's mass and made it the second-brightest star in the sky. Now, a team of astronomers has used extensive new observations to create the first high-resolution 3-D model of the expanding cloud produced by this outburst.

"Our model indicates that this vast shell of gas and dust has a more complex origin than is generally assumed," said Thomas Madura, a NASA Postdoctoral Program fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and a member of the study team. "For the first time, we see evidence suggesting that intense interactions between the stars in the central binary played a significant role in sculpting the nebula we see today."


NASA Goddard astrophysicists Ted Gull and Tom Madura discuss Eta Carinae and their new model of the Homunculus Nebula, a shell of gas and dust ejected during the star's mid-19th century eruption.

Image Credit: NASA's Goddard Space Flight Center

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 over two nights in March 2012, 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, fully 3-D model of the Homunculus Nebula. The new model contains none of the assumptions about the cloud's symmetry found in previous studies. 

The shape model, which is now published by the journal Monthly Notices of the Royal Astronomical Society, 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.   

"Our next step was to process all of this using 3-D modeling software I developed in collaboration with Nico Koning from the University of Calgary in Canada. The program is simply called 'Shape,' and it analyzes and models the three-dimensional motions and structure of nebulae in a way that can be compared directly with observations," said lead researcher Wolfgang Steffen, an astrophysicist at the Ensenada campus of the National Autonomous University of Mexico.

The new shape model confirms several features identified by previous studies, including pronounced holes located at the ends of each lobe and the absence of any extended molecular hydrogen emission from a dust skirt apparent in visible light near the center of the nebula. New features include curious arm-like protrusions emanating from each lobe near the dust skirt; vast, deep trenches curving along each lobe; and irregular divots on the side facing away from Earth.       

"One of the questions we set out to answer with this study is whether the Homunculus contains any imprint of the star's binary nature, since previous efforts to explain its shape have assumed that both lobes were more or less identical and symmetric around their long axis," explained team member Jose Groh, an astronomer at Geneva University in Switzerland. "The new features strongly suggest that interactions between Eta Carinae's stars helped mold the Homunculus." 

Every 5.5 years, when their orbits carry them to their closest approach, called periastron, the immense and brilliant stars of Eta Carinae are only as far apart as the average distance between Mars and the sun. Both stars possess powerful gaseous outflows called stellar winds, which constantly interact but do so most dramatically during periastron, when the faster wind from the smaller star carves a tunnel through the denser wind of its companion. The opening angle of this cavity closely matches the length of the trenches (130 degrees) and the angle between the arm-like protrusions (110 degrees), indicating that the Homunculus likely continues to carry an impression from a periastron interaction around the time of the Great Eruption. 

Once the researchers had developed their Homunculus model, they took things one step further. They converted it to a format that can be used by 3-D printers and made the file available along with the published paper.

"Now anyone with access to a 3-D printer can produce their own version of this incredible object," said Goddard astrophysicist Theodore Gull, who is also a co-author of the paper. "While 3-D-printed models will make a terrific visualization tool for anyone interested in astronomy, I see them as particularly valuable for the blind, who now will be able to compare embossed astronomical images with a scientifically accurate representation of the real thing."

Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Maryland

Francis Reddy | Eurek Alert!
Further information:
http://www.nasa.gov/content/goddard/astronomers-bring-the-third-dimension-to-a-doomed-stars-outburst/#.U7xPJrGNyyc

More articles from Physics and Astronomy:

nachricht LIGO confirms RIT's breakthrough prediction of gravitational waves
12.02.2016 | Rochester Institute of Technology

nachricht Milestone in physics: gravitational waves detected with the laser system from LZH
12.02.2016 | Laser Zentrum Hannover e.V.

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Production of an AIDS vaccine in algae

Today, plants and microorganisms are heavily used for the production of medicinal products. The production of biopharmaceuticals in plants, also referred to as “Molecular Pharming”, represents a continuously growing field of plant biotechnology. Preferred host organisms include yeast and crop plants, such as maize and potato – plants with high demands. With the help of a special algal strain, the research team of Prof. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam strives to develop a more efficient and resource-saving system for the production of medicines and vaccines. They tested its practicality by synthesizing a component of a potential AIDS vaccine.

The use of plants and microorganisms to produce pharmaceuticals is nothing new. In 1982, bacteria were genetically modified to produce human insulin, a drug...

Im Focus: The most accurate optical single-ion clock worldwide

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...

Im Focus: Goodbye ground control: autonomous nanosatellites

The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.

Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...

Im Focus: Flow phenomena on solid surfaces: Physicists highlight key role played by boundary layer velocity

Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.

The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).

Im Focus: New study: How stable is the West Antarctic Ice Sheet?

Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels

A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Symposium on Climate Change Adaptation in Africa 2016

12.02.2016 | Event News

Travel grants available: Meet the world’s most proficient mathematicians and computer scientists

09.02.2016 | Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

 
Latest News

LIGO confirms RIT's breakthrough prediction of gravitational waves

12.02.2016 | Physics and Astronomy

Gene switch may repair DNA and prevent cancer

12.02.2016 | Life Sciences

Using 'Pacemakers' in spinal cord injuries

12.02.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>