Balloon Bubble Barnard 68 (APOD 2009 June 23)

Comments and questions about the APOD on the main view screen.
Post Reply
User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Balloon Bubble Barnard 68 (APOD 2009 June 23)

Post by neufer » Tue Jun 23, 2009 4:42 pm

http://apod.nasa.gov/apod/ap090623.html

http://antwrp.gsfc.nasa.gov/apod/ap090522.html
http://antwrp.gsfc.nasa.gov/apod/ap090425.html

------------------------------------------------------
http://en.wikipedia.org/wiki/Barnard_68 wrote:
<<Barnard 68 is a molecular cloud, dark absorption nebula or Bok globule, towards the southern constellation Ophiuchus and well within our own galaxy at a distance of only 400 or so light-years, so close that not a single star can be seen between it and the Sun. American astronomer Edward Emerson Barnard added this nebula to his catalogue of dark nebulae in 1919. He published his catalogue in 1927, at which stage it included some 350 objects. Because of its opacity, its interior is extremely cold, its temperature being about 16 K. Its mass is about twice that of the Sun and it measures about half a light-year across. Despite being opaque at visible-light wavelengths, use of the Very Large Telescope at Cerro Paranal has revealed the presence of about 3,700 blocked background Milky Way stars, some 1,000 of which are visible at infrared wavelengths. Careful measurements of the degree of obscuration resulted in a finely sampled and accurate mapping of the dust distribution inside the cloud. Having a dark cloud in the solar neighbourhood greatly facilitates observation and measurement. If not disrupted by external forces, the stability of dust clouds is a fine balance between outward pressure caused by the heat or pressure of the cloud's contents, and inward gravitational forces generated by the same particles. This causes the cloud to wobble or oscillate in a manner not unlike that of a large soap bubble or a water-filled balloon which is jiggled. In order for the cloud to become a star, gravity must gain the upper hand long enough to cause the collapse of the cloud and reach a temperature and density where fusion can be sustained. When this happens, the much smaller size of the star's envelope signals a new balance between greatly increased gravity and radiation pressure. Barnard 68's well-defined edges and other features show that it is on the verge of gravitational collapse within the next 100,000 years or so, and is on its way to becoming a star.
------------------------------------------------------
http://en.wikipedia.org/wiki/Edward_Emerson_Barnard wrote:
<<Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer. He was commonly known as E. E. Barnard, and was recognized as a gifted observational astronomer. Barnard was born in Nashville, Tennessee, to Reuben Barnard and Elizabeth Jane Barnard (née Haywood), and had one brother. His father died before his birth, so he grew up in an impoverished family and did not receive much in the way of formal education. His first interest was in the field of photography, and he became a photographer's assistant at the age of nine.

He later developed an interest in astronomy. In 1876 he purchased a 5-inch (130 mm) refractor telescope, and in 1881 he discovered his first comet. (But he failed to announce his discovery). He found his second comet later the same year and a third in 1882. While he was still working at a photography studio he was married to the English-born woman Rhoda Calvert in 1881. In the 1880s a Hulbert Harrington Warner offered US $200 per discovery of a new comet. Edward discovered a total of eight, and used the money to build a house for himself and his bride.

With his name being brought to the attention of amateur astronomers in Nashville, they collectively raised enough money to give Edward a fellowship to Vanderbilt University. Barnard never graduated from the school, but he did receive the only honorary degree Vanderbilt has ever awarded. He joined the staff of the Lick Observatoryin 1887, though he later clashed with the director, Edward S. Holden, over access to observing time on the larger instruments and other issues of research and management.

In 1892 he made observations of a nova and was the first to notice the gaseous emissions, thus deducing that it was a stellar explosion. The same year he also discovered Amalthea, the fifth moon of Jupiter. He was the first to discover a new moon of Jupiter since Galileo Galilei in 1609. This was the last satellite discovered by visual observation (rather than by examining photographic plates or other recorded images).

In 1895 he joined the University of Chicago as professor of astronomy. There he was able to use the 40-inch (1,000 mm) telescope at Yerkes Observatory. Much of his work during this period was taking photographs of the Milky Way. Together with Max Wolf, he discovered that certain dark regions of the galaxy were actually clouds of gas and dust that obscured the more distant stars in the background. From 1905, his niece Mary R. Calvert worked as his assistant and computer.

The faint Barnard's Star is named for Edward Barnard after he discovered in 1916 that it had a very large proper motion, relative to other stars. This is the second nearest star system to the Sun, second only to the Alpha Centauri system.

He was also a pioneering astrophotographer. He cataloged a series of dark nebula giving them numerical designation akin to the Messier catalog. They begin with Barnard 1 and end with Barnard 366. He published his initial list with the 1919 paper in the Astrophysical Journal, "On the Dark Markings of the Sky with a Catalogue of 182 such Objects".

He died on February 6, 1923 in Williams Bay, Wisconsin, and was buried in Nashville. After his death, his exceptional collection of photographs was published in 1927 as A Photographic Atlas of Selected Regions of the Milky Way.>>
------------------------------------------------------
http://fireballs-meteorites.blogspot.com/2008/10/october-2008.html wrote: Transient Sky byCarl Hergenrother
Mon, 13 Oct 2008 00:32 UTC

<<Nearly a month ago two Japanese amateur astronomers re-discovered Comet Giacobini which had been lost for 111 years. Now this weekend comes word that an object found by professional astronomer Andrea Boattini of the Catalina Sky Survey is also a re-discovery of a long-lost comet. After Boattini’s find was officially announced, Maik Meyer of Limburg, Germany suggested that this comet was actually the same as a comet last seen on 1892 Dec 8.

Comet Barnard 3 was found by Edward Emerson Barnard on 1892 Oct 13. It was the first comet to be discovered with the then new technique of astro-photography. Before this, all comets were discovered by astronomers using only their eyes though many were found while looking through a telescope. The comet was as bright as 12th magnitude in 1892 which is much brighter than its current brightness of 17th magnitude. It is possible that similar to Comet Giacobini, this comet was experiencing an outburst in 1892 that made it brighter than usual. The reason it wasn’t found during the next 116 years was because its usual brightness was too faint for most of the comet searchers. Today thanks to computers and CCD (digital) cameras, the current generation of comet and asteroid surveys can cover a good fraction of the sky to very faint brightnesses.

Since the comet was already credited to Boattini before the identification with Comet Barnard 3 was noticed, the comet will be officially named Comet Barnard-Boattini. Analysis published by the Central Bureau for Astronomical Telegrams on IAUC 8995 find that the comet’s current orbit takes it from near the orbit of Jupiter (sun-comet distance of 5.33 AU) to just outside the Earth’s orbit (sun-comet distance of 1.15 AU). Back in 1892 the comet only got as close to the Sun as 1.43 AU. The comet has made 20 orbits of the Sun between 1892 and 2008. It will make its closest approach to the Sun on Oct 24 and to the Earth around Oct 22 at a distance of 0.19 AU.>>
------------------------------------------------------
Art Neuendorffer

billclawson
Asternaut
Posts: 3
Joined: Mon Aug 04, 2008 8:59 pm
Contact:

Re: Balloon Bubble Barnard 68 (APOD 2009 June 23)

Post by billclawson » Tue Jun 23, 2009 7:24 pm

Everyone knows there's a giant amoeba in the center of B68! http://en.wikipedia.org/wiki/The_Immuni ... Star_Trek) No other explanation is necesary. :mrgreen:

Post Reply