Eta Carinae and the Expanding Homunculus Nebula

Eta Carinae and the Expanding Homunculus Nebula 

Image Credit: Hubble, NASA, ESA; Processing & Copyright: First Light, J. L. Dauvergne, P. Henarejos

How did the Eta Carinae star system create this unusual expanding nebula? No one knows for sure.

About 170 years ago, the southern star system Eta Carinae (Eta Car) mysteriously became the second brightest star system in the night sky.

Twenty years later, after ejecting more mass than our Sun, Eta Car unexpectedly faded. Somehow, this outburst appears to have created the Homunculus Nebula.

The three-frame video features images of the nebula taken by the Hubble Space Telescope in 1995, 2001, and 2008.

The Homonculus nebula's center is lit by light from a bright central star, while the surrounding regions are expanding lobes of gas laced with filaments of dark dust.

Jets bisect the lobes emanating from the central stars. Expanding debris includes streaming whiskers and bow shocks caused by collisions with previously existing material.

Eta Carinae still undergoes unexpected outbursts, and its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.

Mobile LIDAR technology expanding rapidly

LIDAR can capture considerable data on nearby terrain, as seen in this image of an ordinary highway. (Image courtesy of Oregon State University).

Imagine driving down a road a few times and obtaining in an hour more data about the surrounding landscape than a crew of surveyors could obtain in months.

Such is the potential of mobile LIDAR, a powerful technology that's only a few years old and promises to change the way we see, study and record the world around us.

It will be applied in transportation, hydrology, forestry, virtual tourism and construction - and almost no one knows anything about it.

That may change with a new report on the uses and current technology of mobile LIDAR, which has just been completed and presented to the Transportation Research Board of the National Academy of Sciences.

It will help more managers and experts understand, use and take advantage of this science.

Facing Constraints
The full exploitation of this remarkable technology, however, faces constraints.

• Too few experts are trained to use it, 
• too few educational programs exist to teach it, 
• mountains of data are produced that can swamp the computer capabilities of even large agencies, and 
• lack of a consistent data management protocol clogs the sharing of information between systems.

"A lot of people and professionals still don't even know what mobile LIDAR is or what it can do," said Michael Olsen, an assistant professor of civil engineering at Oregon State University, and lead author of the new report. "And the technology is changing so fast it's hard for anyone, even the experts, to keep up.

"When we get more people using mobile LIDAR and we work through some of the obstacles, it's going to reduce costs, improve efficiency, change many professions and even help save lives," Olsen said.

This lidar (laser range finder) may be used to scan buildings, rock formations, etc., to produce a 3D model. 

The LIDAR can aim its laser beam in a wide range: its head rotates horizontally; a mirror tilts vertically. 

The laser beam is used to measure the distance to the first object on its path.

LIDAR
LIDAR, which stands for 'light detecting and ranging', has been used for 20 years, primarily in aerial mapping. Pulses of light up to one million times a second bounce back from whatever they hit, forming a highly detailed and precise map of the landscape.

But mobile LIDAR used on the ground, with even more powerful computer systems, is still in its infancy and has only been commercially available for five years.

Mobile LIDAR, compared to its aerial counterpart, can provide 10 to 100 times more data points that hugely improve the resolution of an image. Moving even at highway speeds, a technician can obtain a remarkable, three-dimensional view of the nearby terrain.