The Heart Nebula, IC 1805, Sharpless 2-190, lies some 7500 light years away from Earth and is located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. It was discovered by William Herschel on 3 November 1787; this is an emission nebula showing darker dust lanes. The brightest part of this nebula is separately classified as NGC 896, because it was the first part of this nebula to be discovered; the nebula's intense red output and its configuration are driven by the radiation emanating from a small group of stars near the nebula's center. This open cluster of stars known as Melotte 15 contains a few bright stars nearly 50 times the mass of our Sun, many more dim stars that are only a fraction of our Sun's mass. Soul Nebula List of NGC objects Heart Nebula at Atlas of the Universe NASA Astronomy Picture of the Day: Heart Nebula
The Trifid Nebula is an H II region located in Sagittarius. It was discovered by Charles Messier on June 5, 1764, its name means'divided into three lobes'. The object is an unusual combination of an open cluster of stars. Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, is thus a perennial favorite of amateur astronomers; the Trifid Nebula is a star-forming region in the Scutum spiral arm of the Milky Way. The most massive star that has formed in this region is HD 164492A, an O7.5III star with a mass more than 20 times the mass of the Sun. This star is surrounded by a cluster of 3100 young stars; the Trifid Nebula was the subject of an investigation by astronomers using the Hubble Space Telescope in 1997, using filters that isolate emission from hydrogen atoms, ionized sulfur atoms, doubly ionized oxygen atoms. The images were combined into a false-color composite picture to suggest how the nebula might look to the eye; the close-up images show a dense cloud of dust and gas, a stellar nursery full of embryonic stars.
This cloud is about 8 ly away from the nebula's central star. A stellar jet is about 0.75 ly long. The jet's source is a young stellar object deep within the cloud. Jets are the exhaust gasses of star formation and radiation from the nebula's central star makes the jet glow; the images showed a finger-like stalk to the right of the jet. It points from the head of the dense cloud directly toward the star; this stalk is a prominent example of evaporating gaseous globules, or'EGGs'. The stalk has survived because its tip is a knot of gas, dense enough to resist being eaten away by the powerful radiation from the star. In January 2005, NASA's Spitzer Space Telescope discovered 30 embryonic stars and 120 newborn stars not seen in visible light images, it is 5000 ly away from Earth. Its apparent magnitude is 6.3. List of Messier objects List of nebulae Messier object New General Catalogue Trifid Nebula in fiction Wikipedia Project: Astronomical Objects The Alternative Factor Islands Spitzer IR Trifid discoveries Messier 20, SEDS Messier pages Trifid Nebula at ESA/Hubble Merrifield, Michael.
"M20 – Trifid Nebula". Deep Sky Videos. Brady Haran; the Trifid Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Sky Map and images Trifid Nebula at Constellation Guide
The California Nebula is an emission nebula located in the constellation Perseus. It is so named because it appears to resemble the outline of the US State of California on long exposure photographs, it is 2.5° long on the sky and, because of its low surface brightness, it is difficult to observe visually. It can be observed with a Hβ filter in a rich-field telescope under dark skies, it lies at a distance of about 1,000 light years from Earth. Its fluorescence is due to excitation of the Hβ line in the nebula by the nearby prodigiously energetic O7 star, xi Persei; the California Nebula was discovered by E. E. Barnard in 1884. By coincidence, the California Nebula transits in the zenith in central California as the latitude matches the declination of the object. NGC 1499 at SEDS Menkhib and the California Nebula by the Wide-field Infrared Survey Explorer
NGC 1579 is a diffuse nebula located in the constellation of Perseus. It is referred to as the Northern Trifid because of its similar appearance to the Trifid Nebula, located in the southern celestial hemisphere of the sky, it is a region of star formation. The star cluster contains the emission-line star LkHα 101, which provides much of the ionizing radiation in the nebula. NGC 1579 lies within a giant molecular cloud known as the California Molecular Cloud
A nebula is an interstellar cloud of dust, hydrogen and other ionized gases. The term was used to describe any diffuse astronomical object, including galaxies beyond the Milky Way; the Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others. Most nebulae are of vast size. A nebula, visible to the human eye from Earth would appear larger, but no brighter, from close by; the Orion Nebula, the brightest nebula in the sky and occupying an area twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffuse they can only be detected with long exposures and special filters.
Some nebulae are variably illuminated by T Tauri variable stars. Nebulae are star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas and other materials "clump" together to form denser regions, which attract further matter, will become dense enough to form stars; the remaining material is believed to form planets and other planetary system objects. Around 150 AD, Claudius Ptolemaeus recorded, in books VII–VIII of his Almagest, five stars that appeared nebulous, he noted a region of nebulosity between the constellations Ursa Major and Leo, not associated with any star. The first true nebula, as distinct from a star cluster, was mentioned by the Persian astronomer Abd al-Rahman al-Sufi, in his Book of Fixed Stars, he noted "a little cloud". He cataloged the Omicron Velorum star cluster as a "nebulous star" and other nebulous objects, such as Brocchi's Cluster; the supernova that created the Crab Nebula, the SN 1054, was observed by Arabic and Chinese astronomers in 1054.
In 1610, Nicolas-Claude Fabri de Peiresc discovered the Orion Nebula using a telescope. This nebula was observed by Johann Baptist Cysat in 1618. However, the first detailed study of the Orion Nebula was not performed until 1659, by Christiaan Huygens, who believed he was the first person to discover this nebulosity. In 1715, Edmund Halley published a list of six nebulae; this number increased during the century, with Jean-Philippe de Cheseaux compiling a list of 20 in 1746. From 1751 to 1753, Nicolas Louis de Lacaille cataloged 42 nebulae from the Cape of Good Hope, most of which were unknown. Charles Messier compiled a catalog of 103 "nebulae" by 1781; the number of nebulae was greatly increased by the efforts of William Herschel and his sister Caroline Herschel. Their Catalogue of One Thousand New Nebulae and Clusters of Stars was published in 1786. A second catalog of a thousand was published in 1789 and the third and final catalog of 510 appeared in 1802. During much of their work, William Herschel believed that these nebulae were unresolved clusters of stars.
In 1790, however, he discovered a star surrounded by nebulosity and concluded that this was a true nebulosity, rather than a more distant cluster. Beginning in 1864, William Huggins examined the spectra of about 70 nebulae, he found that a third of them had the emission spectrum of a gas. The rest thus were thought to consist of a mass of stars. A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star Merope matched the spectra of the Pleiades open cluster, thus the nebula radiates by reflected star light. About 1923, following the Great Debate, it had become clear that many "nebulae" were in fact galaxies far from our own. Slipher and Edwin Hubble continued to collect the spectra from many different nebulae, finding 29 that showed emission spectra and 33 that had the continuous spectra of star light. In 1932, Hubble announced that nearly all nebula are associated with stars, their illumination comes from star light, he discovered that the emission spectrum nebulae are nearly always associated with stars having spectral classifications of B or hotter, while nebulae with continuous spectra appear with cooler stars.
Both Hubble and Henry Norris Russell concluded that the nebulae surrounding the hotter stars are transfomed in some manner. There are a variety of formation mechanisms for the different types of nebulae; some nebulae form from gas, in the interstellar medium while others are produced by stars. Examples of the former case are giant molecular clouds, the coldest, densest phase of interstellar gas, which can form by the cooling and condensation of more diffuse gas. Examples of the latter case are planetary nebulae formed from material shed by a star in late stages of its stellar evolution. Star-forming regions are a class of emission nebula associated with giant molecular clouds; these form as a molecular cloud collapses under its own weight. Massive stars may form in the center, their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths; the region of ionized hydrogen surrounding th
NGC 1491 is a bright nebula in the constellation of Perseus. It is known as LBN 704
NGC 7380 is an open cluster discovered by Caroline Herschel in 1787. William Herschel included his sister's discovery in his catalog, labelled it H VIII.77. It is known as 142 in the 1959 Sharpless catalog; this reasonably large nebula is located in Cepheus. It is difficult to observe visually requiring dark skies and an O-III filter. Located 7200 light years away, the Wizard nebula, surrounds developing open star cluster NGC 7380. Visually, the interplay of stars and dust has created a shape that appears to some like a fictional medieval sorcerer; the active star forming region spans about 100 light years, making it appear larger than the angular extent of the Moon. The Wizard Nebula can be located with a small telescope toward the constellation of the King of Aethiopia. Although the nebula may last only a few million years, some of the stars being formed may outlive our Sun. NGC 7380 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Sky Map and images South Common Observatory - Images of the Wizard Nebula NASA APOD mentioning the Wizard Nebula