Showing posts with label Red Giant. Show all posts
Showing posts with label Red Giant. Show all posts

Friday, September 7, 2012

The waning of a gibbous Moon

The waning gibbous Moon lies between Jupiter and Aldebaran tonight, rising from the north-east in late evening.

A Gibbous Moon
A gibbous moon is one of the phases of the Moon, when the size of the illuminated portion is greater than half but not a full Moon.

The period between a first quarter moon and a full moon is known as a waxing gibbous moon, because the illuminated region of the Moon is increasing from day to day. 


After it becomes a full moon, but hasn’t reached the last quarter, the Moon is called a waning gibbous moon.

Alderban
Aldebaran (Alpha Tauri) is a red giant star located about 65 light years away in the zodiac constellation of Taurus.

Saturday, July 7, 2012

NASA Hubble Image: Camelopardalis, A Red Giant Blows a Bubble

Camelopardalis, or U Cam for short, is a star nearing the end of its life. As stars run low on fuel, they become unstable.

Every few thousand years, U Cam coughs out a nearly spherical shell of gas as a layer of helium around its core begins to fuse.

The gas ejected in the star’s latest eruption is clearly visible in this picture as a faint bubble of gas surrounding the star.

U Cam is an example of a carbon star, a rare type of star with an atmosphere that contains more carbon than oxygen.

Due to its low surface gravity, typically as much as half of the total mass of a carbon star may be lost by way of powerful stellar winds.

Located in the constellation of Camelopardalis (The Giraffe), near the North Celestial Pole, U Cam itself is much smaller than it appears in this Hubble image.

In fact, the star would easily fit within a single pixel at the center of the image.

Its brightness, however, is enough to saturate the camera's receptors, making the star look much larger than it is.

The shell of gas, which is both much larger and much fainter than its parent star, is visible in intricate detail in Hubble’s portrait.

This phenomenon is often quite irregular and unstable, but this shell of gas expelled from U Cam is almost perfectly spherical.

Image Credit: ESA/NASA

The Star, which was then called Camelopardus, was introduced by Petrus Plancius in the early 1600's. He was a Dutch astronomer, cartographer and clergyman.

Thursday, March 29, 2012

Wings: Planetary nebula NGC 6881 in the constellation of Cygnus

Planetary nebula NGC 6881 lies in the constellation of Cygnus. Its "wings" spread across about one light-year. 

A dying star about 60% of the mass of the sun lies at the core of the NGC 6881. 

A planetary nebula arises when a dying star, a red giant, flings off its outer layers. 

Planetary nebulas were misnamed by early discoverers, who thought the objects were giant planets. 

Credit: ESA/NASA Hubble

Friday, July 31, 2009

Red Super Giant Betelgeuse: Constellation Orion the Hunter

Credit: Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA
This image from the Hubble Space Telescope shows Betelgeuse, the red supergiant that marks the shoulder of the winter constellation Orion the Hunter (diagram at right).