The Vela supernova remnant is a supernova remnant in the southern constellation Vela. Its source Type II supernova exploded approximately 11,000–12,300 years ago (and was about 800 light-years away). The association of the Vela supernova remnant with the Vela pulsar, made by astronomers at the University of Sydney in 1968, was direct observational evidence that supernovae form neutron stars.
The Vela supernova remnant includes NGC 2736. It also overlaps the Puppis Supernova Remnant, which is four times more distant. Both the Puppis and Vela remnants are among the largest and brightest features in the X-ray sky.
The Vela supernova remnant (SNR) is one of the closest known to us. The Geminga pulsar is closer (and also resulted from a supernova), and in 1998 another near-Earth supernova remnant was discovered, RX J0852.0-4622, which from our point of view appears to be contained in the southeastern part of the Vela remnant. One estimate of its distance puts it only 200 parsecs away (about 650 ly), closer than the Vela remnant, and, surprisingly, it seems to have exploded much more recently, in the last thousand years, because it is still radiating gamma rays from the decay of titanium-44. This remnant was not seen earlier because in most wavelengths, it is lost because of the presence of the Vela remnant.
|Vela Supernova Remnant|
The northern portion of the Vela Supernova Remnant
Credit: Harel Boren
|Observation data: J2000.0 epoch|
|Right ascension||08h 35m 20.66s|
|Declination||−45° 10′ 35.2″|
|Distance||815±98 ly (250±30 pc)|
|Apparent magnitude (V)||12|
|Apparent dimensions (V)||8 degrees (approx.)|
|Designations||Vela XYZ, Gum 16, SNR G263.9-03.3, 1E 0840.0-4430, RE J083854-430902|
CG 4, commonly referred to as God's Hand, is a star-forming region located in the Puppis constellation, about 1,300 light-years (400 pc) from Earth. It is one of several objects referred to as "cometary globules", because its shape is similar to that of a comet. It has a dense head formed of gas and dust, which is around 1.5 ly (0.46 pc) in diameter, and an elongated faint tail around 8 ly (2.5 pc) in length.CG 4, and the nearby cometary globules, generally point away from the Vela Supernova Remnant, located at the center of the Gum Nebula.Gum Nebula
The Gum Nebula (Gum 12) is an emission nebula that extends across 36° in the southern constellations Vela and Puppis. It lies roughly 350 parsecs from the Earth. Hard to distinguish, it was widely believed to be the greatly expanded (and still expanding) remains of a supernova that took place about a million years ago. More recent research suggests it may be an evolved H II region. It contains the 11,000-year-old Vela Supernova Remnant, along with the Vela Pulsar.
The Gum Nebula contains about 32 cometary globules. These dense cloud cores are subject to such strong radiation from O-type stars γ2 Vel and ζ Pup and formerly the progenitor of the Vela Supernova Remnant that the cloud cores evaporate away from the hot stars into comet-like shapes. Like ordinary Bok globules, cometary globules are believed to be associated with star formation.It is named after its discoverer, the Australian astronomer Colin Stanley Gum (1924–1960). Gum had published his findings in 1955 in a work called A study of diffuse southern H-alpha nebulae (see Gum catalog).Gum catalog
The Gum catalog is an astronomical catalog of 84 emission nebulae in the southern sky. It was made by the Australian astronomer Colin Stanley Gum (1924-1960) at Mount Stromlo Observatory using wide field photography. Gum published his findings in 1955 in a study entitled A study of diffuse southern H-alpha nebulae which presented a catalog of 84 nebulae or nebular complexes. Similar catalogs include the Sharpless catalog and the RCW catalog, and many of the Gum objects are repeated in these other catalogs.
The Gum Nebula is named for Gum, who discovered it as Gum 12; it is an emission nebula that can be found in the southern constellations Vela and Puppis.History of supernova observation
The known history of supernova observation goes back to 185 AD, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind. Several additional supernovae within the Milky Way galaxy have been recorded since that time, with SN 1604 being the most recent supernova to be observed in this galaxy.Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies. Successful models of supernova behavior have also been developed, and the role of supernovae in the star formation process is now increasingly understood.List of largest nebulae
Below is a list of the largest nebulae so far discovered, ordered by size.List of stars in Vela
This is the list of notable stars in the constellation Vela, sorted by decreasing brightness.
This constellation's Bayer designations (Greek-letter star names) were given while it was still considered part of the constellation of Argo Navis. After Argo Navis was broken up into Carina, Vela, and Puppis, these Greek-letter designations were kept, so that Vela does not have a full complement of Greek-letter designations. For example, since Argo Navis's alpha star went to Carina, there is no Alpha Velorum.NGC 2736
NGC 2736 (also known as the Pencil Nebula) is a small part of the Vela Supernova Remnant, located near the Vela Pulsar in the constellation Vela. The nebula's linear appearance triggered its popular name. It resides about 815 light-years (250 parsecs) away from the Solar System. It is thought to be formed from part of the shock wave of the larger Vela Supernova Remnant. The Pencil Nebula is moving at roughly 644,000 kilometers per hour (400,000 miles per hour).Near-Earth supernova
A near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth (roughly less than 10 to 300 parsecs (30 to 1000 light-years) away) to have noticeable effects on Earth's biosphere.
Historically, each near-Earth supernova explosion has been associated with a global warming of around 3–4 °C (5–7 °F). An estimated 20 supernovae explosions have happened within 300 pc of the Earth over the last 11 million years. Type II supernovae explosions are expected to occur in active star-forming regions, with 12 such OB associations being located within 650 pc of the Earth. At present, there are six near-Earth supernova candidates within 300 pc.Outline of astronomy
The following outline is provided as an overview of and topical guide to astronomy:
Astronomy – studies the universe beyond Earth, including its formation and development, and the evolution, physics, chemistry, meteorology, and motion of celestial objects (such as galaxies, planets, etc.) and phenomena that originate outside the atmosphere of Earth (such as the cosmic background radiation).PSR J0855−4644
PSR J0855-4644 is a pulsar in the constellation Vela, and could be associated with supernova remnant RX J0852.0-4622 which may have exploded about 1200 years ago.Pulsar wind nebula
A pulsar wind nebula (PWN, plural PWNe), sometimes called a plerion (derived from the Greek "πλήρης", pleres, meaning "full"), is a type of nebula found inside the shells of supernova remnants (SNRe) that is powered by pulsar winds generated by its central pulsar. These nebulae were discovered in 1976 as small depressions at radio wavelengths near the centre of supernova remnants. They have since been found to be X-ray emitters and are possibly gamma ray sources.Puppis A
Puppis A (Pup A) is a supernova remnant (SNR) about 100 light-years in diameter and roughly 6500–7000 light-years distant. Its apparent angular diameter is about 1 degree. The light of the supernova explosion reached Earth approximately 3700 years ago. Although it overlaps the Vela Supernova Remnant, it is four times more distant.
A hypervelocity neutron star known as the Cosmic Cannonball has been found in this SNR.RX J0852.0−4622
RX J0852.0−4622 (also known as G266.2−1.2) is a supernova remnant. The remnant is located in the southern sky in the constellation Vela ("sail"), and sits (in projection) inside the much larger and older Vela Supernova Remnant. For this reason, RX J0852.0−4622 is often referred to as Vela Junior.
It was found in 1998 when gamma ray emissions from the decay of 44Ti nuclei were discovered using the Imaging Compton Telescope (COMPTEL).
The distance to this object is controversial, but some scientists argue that the supernova remnant is only 650–700 light-years away, and exploded comparatively recently (as seen from Earth), perhaps within the last 800 years. If this distance is accurate, a possible stellar remnant could be the pulsar PSR J0855−4644.
If the remnant is indeed young and nearby, its corresponding supernova should have been visible from the Earth in about the year 1250. One difficulty with this interpretation is that there are no contemporary written reports of any supernova at that time or in that part of the sky.
Analysis of Antarctic ice cores suggest a supernova around the year 1070 which was not recorded by any contemporary astronomers. This supernova, at 46 degrees south, may have been too far south for observers in the northern hemisphere to have noticed it, especially if it obtained peak brightness during the northern summer. At this declination, the supernova would be invisible above about 45 degrees north, making it invisible to the majority of Europe.
The central compact object (CCO) was discovered in 2001. In the initial Chandra X-ray image and deeper images thereafter, no pulsations were detected from the compact remnant, which is believed to be a neutron star.Vela (constellation)
Vela is a constellation in the southern sky. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the brightest Wolf-Rayet star in the sky. Delta and Kappa Velorum, together with Epsilon and Iota Carinae, form the asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system.Vela Pulsar
The Vela Pulsar (PSR J0835-4510 or PSR B0833-45) is a radio, optical, X-ray- and gamma-emitting pulsar associated with the Vela Supernova Remnant in the constellation of Vela.Younger Dryas
The Younger Dryas (c. 12,900 to c. 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum started receding around 20,000 BP. It is named after an indicator genus, the alpine-tundra wildflower Dryas octopetala, as its leaves are occasionally abundant in the Late Glacial, often minerogenic-rich, like the lake sediments of Scandinavian lakes.
Physical evidence of a sharp decline in temperature over most of the Northern Hemisphere has been discovered by geological research. This temperature change occurred at the end of what the earth sciences refer to as the Pleistocene epoch and immediately before the current, warmer Holocene epoch. In archaeology, this time frame coincides with the final stages of the Upper Paleolithic in many areas.
The Younger Dryas was the most recent and longest of several interruptions to the gradual warming of the Earth's climate since the severe Last Glacial Maximum, c. 27,000 to 24,000 years BP. The change was relatively sudden, taking place in decades, and it resulted in a decline of 2 to 6 degrees Celsius (3.6 to 10.8 degrees Fahrenheit) and advances of glaciers and drier conditions, over much of the temperate northern hemisphere. It is thought to have been caused by a decline in the strength of the Atlantic meridional overturning circulation, which transports warm water from the Equator towards the North Pole, in turn thought to have been caused by an influx of fresh cold water from North America to the Atlantic.
The Younger Dryas was a period of climatic change, but the effects were complex and variable. In the Southern Hemisphere and some areas of the Northern Hemisphere, such as southeastern North America, there was a slight warming.