NGC 6302

NGC 6302, also called the Bug Nebula or Butterfly Nebula, is a bipolar planetary nebula in the constellation Scorpius. The structure in the nebula is among the most complex ever observed in planetary nebulae. The spectrum of NGC 6302 shows that its central star is one of the hottest stars known, with a surface temperature in excess of 250,000 degrees Celsius, implying that the star from which it formed must have been very large.

The central star, a white dwarf, was identified in 2009 , using the upgraded Wide Field Camera 3 on board the Hubble Space Telescope.(Szyszka et al. 2009) The star has a current mass of around 0.64 solar masses. It is surrounded by a dense equatorial disc composed of gas and dust. This dense disc is postulated to have caused the star's outflows to form a bipolar structure (Gurzadyan 1997) similar to an hour-glass. This bipolar structure shows features such as ionization walls, knots and sharp edges to the lobes.

NGC 6302
Emission nebula
Planetary nebula
NGC 6302 Hubble 2009.full
NGC 6302, as taken by Hubble Space Telescope
Observation data: J2000 epoch
Right ascension 17h 13m 44.211s[1]
Declination−37° 06′ 15.94″[1]
Distance3.4 ± 0.5 kly (1.04 ± 0.16 kpc)[2] ly
Apparent magnitude (V)7.1B[1]
Apparent dimensions (V)>3′.0[2]
Physical characteristics
Radius>1.5 ± 0.2 ly[3] ly
Absolute magnitude (V)-3.0B +0.4
Notable featuresDual chemistry, hot central star
DesignationsBipolar Nebula,[1] Bug Nebula,[1]
PK 349+01 1,[1] Butterfly Nebula,[5][6] Sharpless 6, RCW 124, Gum 60, Caldwell 69

Observation history

As it is included in the New General Catalogue, this object has been known since at least 1888.[7] The earliest known study of NGC 6302 is by Edward Emerson Barnard, who drew and described it in 1907.[2]

The nebula featured in some of the first images released after the final servicing mission of the Hubble Space Telescope in September 2009.[8]


NGC 6302 has a complex structure, which may be approximated as bipolar with two primary lobes, though there is evidence for a second pair of lobes that may have belonged to a previous phase of mass loss. A dark lane runs through the waist of the nebula obscuring the central star at all wavelengths.[9]

The nebula contains a prominent northwest lobe which extends up to 3′.0 away from the central star and is estimated to have formed from an eruptive event around 1,900 years ago. It has a circular part whose walls are expanding such that each part has a speed proportional to its distance from the central star. At an angular distance of 1.71′ from the central star, the flow velocity of this lobe is measured to be 263 km/s. At the extreme periphery of the lobe, the outward velocity exceeds 600 km/s. The western edge of the lobe displays characteristics suggestive of a collision with pre-existing globules of gas which modified the outflow in that region[2]

Central star

The central star, among the hottest stars known, had escaped detection because of a combination of its high temperature (meaning that it radiates mainly in the ultraviolet), the dusty torus (which absorbs a large fraction of the light from the central regions, especially in the ultraviolet) and the bright background from the star. It was not seen in the first Hubble Space Telescope images;[6] the improved resolution and sensitivity of the new Wide Field Camera 3 of the same telescope later revealed the faint star at the centre.[10] A temperature of 200,000 Kelvin is indicated, and a mass of 0.64 solar masses. The original mass of the star was much higher, but most was ejected in the event which created the planetary nebula. The luminosity and temperature of the star indicate it has ceased nuclear burning and is on its way to becoming a white dwarf, fading at a predicted rate of 1% per year.

Dust chemistry

The prominent dark lane that runs through the centre of the nebula has been shown to have an unusual composition, showing evidence for multiple crystalline silicates, crystalline water ice and quartz, with other features which have been interpreted as the first extra-solar detection of carbonates.[11] This detection has been disputed, due to the difficulties in forming carbonates in a non-aqueous environment.[12] The dispute remains unresolved.

One of the characteristics of the dust detected in NGC 6302 is the existence of both oxygen-bearing silicate molecules and carbon-bearing polycyclic aromatic hydrocarbons (PAHs).[11] Stars are usually either oxygen-rich or carbon-rich, the change from the former to the latter occurring late in the evolution of the star due to nuclear and chemical changes in the star's atmosphere. NGC 6302 belongs to a group of objects where hydrocarbon molecules formed in an oxygen-rich environment[13]

Position of NGC 6302.


  1. ^ a b c d e f (SIMBAD 2007)
  2. ^ a b c d (Meaburn et al. 2005)
  3. ^ Radius = distance × sin(angular size / 2) = 3.4 ± 0.5 kly * sin(>3′.0 / 2) = >1.5 ± 0.2 ly
  4. ^ 7.1B apparent magnitude - 5 * (log10(1040 ± 160 pc distance) - 1) = -3.0B +0.4
    absolute magnitude
  5. ^ (APoD 1998)
  6. ^ a b (APoD 2004)
  7. ^ Many sources credit its discovery to James Dunlop in 1826. E.g. (1) Wolfgang Steinicke, Nebel und Sternhaufen: Geschichte ihrer Entdeckung, Beobachtung und Katalogisierung- von Herschel bis Dreyers, 2009, p.429. (2) Universe Today; (3) Stephen James O'Meara, The Caldwell objects. Cambridge University Press, 2002, p.274..
    (O'Meara argues that Barnard credited it to Dunlop - but may have been mistaken.)
  8. ^ News Release Number: STScI-2009-25: Hubble Opens New Eyes on the Universe [1]
  9. ^ (Matsuura et al. 2005)
  10. ^ (Szyszka et al. 2009)
  11. ^ a b (Kemper et al. 2002)
  12. ^ (Ferrarotti & Gail 2005)
  13. ^ (Matsuura et al. 2005).


  • Nemiroff, R.; Bonnell, J., eds. (June 2, 1998). "NGC 6302: The Butterfly Nebula". Astronomy Picture of the Day. NASA.
  • Nemiroff, R.; Bonnell, J., eds. (May 5, 2004). "NGC 6302: Big, Bright, Bug Nebula". Astronomy Picture of the Day. NASA.
  • Szyszka, C.; Walsh, J. R; Zijlstra, A. A.; Tsamis, Y.G. (2009), "Detection of the Central Star of the Planetary Nebula NGC 6302", Astrophysical Journal Letters, 707 (1): L32–L36, arXiv:0909.5143, Bibcode:2009ApJ...707L..32S, doi:10.1088/0004-637x/707/1/l32
  • Gurzadyan, Grigor A. (1997), The Physics and Dynamics of Planetary Nebulae, Germany: Springer, p. 3, ISBN 978-3-540-60965-0
  • Meaburn, J.; López, J. A.; Steffen, W.; Graham, M. F.; et al. (2005), "The Hubble-Type Outflows from the High-Excitation, Polypolar Planetary Nebula NGC 6302", The Astronomical Journal, 130 (5): 2303–2311, arXiv:astro-ph/0507675, Bibcode:2005AJ....130.2303M, doi:10.1086/496978
  • SIMBAD (January 11, 2007), Results for NGC 6302, SIMBAD, Centre de Données Astronomiques de Strasbourg
  • Kemper, F.; Molster, F. J.; Jaeger, C.; Waters, L.B.F.M. (2002), "The mineral composition and spatial distribution of the dust ejecta of NGC 6302", Astronomy and Astrophysics, 394 (2): 679–690, arXiv:astro-ph/0208110, Bibcode:2002A&A...394..679K, doi:10.1051/0004-6361:20021119
  • Ferrarotti, A. S.; Gail, H.-P. (2005), "Mineral formation in stellar winds. V. Formation of calcium carbonate", Astronomy and Astrophysics, 430 (3): 959–965, Bibcode:2005A&A...430..959F, doi:10.1051/0004-6361:20041856
  • Matsuura, M.; Zijlstra, A. A.; Molster, F.J.; Waters, L. B. F. M.; et al. (2005), "The dark lane of the planetary nebula NGC 6302", Monthly Notices of the Royal Astronomical Society, 359 (1): 383–400, Bibcode:2005MNRAS.359..383M, doi:10.1111/j.1365-2966.2005.08903.x

External links

Coordinates: Sky map 17h 13m 44.211s, −37° 06′ 15.94″

Butterfly Nebula

Butterfly Nebula may refer to:

Planetary Nebula M2-9

NGC 6302, a bipolar planetary nebula in the constellation Scorpius

NGC 2346

Little Dumbbell Nebula

Sadr Region


C69 or C-69 may refer to:

Lockheed C-69 Constellation, a four-engine propeller-driven transport aircraft built by Lockheed between 1943 and 1945

London Underground C69 and C77 Stock, trains used from 1970 to 2014

Corydoras maculifer, the dotted corydoras, a freshwater catfish

Ruy Lopez, Exchange Variation chess openings ECO code

Ocular oncology ICD-10 code

Caldwell 69 (NGC 6302, the Bug Nebula), a planetary nebula in the constellation Scorpius

Caldwell catalogue

The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore as a complement to the Messier catalogue.While the Messier catalogue is used by amateur astronomers as a list of deep-sky objects for observation, Moore noted that Messier's list was not compiled for that purpose and excluded many of the sky's brightest deep-sky objects, such as the Hyades, the Double Cluster (NGC 869 and NGC 884), and the Sculptor Galaxy (NGC 253). The Messier catalogue was actually compiled as a list of known objects that might be confused with comets. Moore also observed that since Messier compiled his list from observations in Paris, it did not include bright deep-sky objects visible in the Southern Hemisphere, such as Omega Centauri, Centaurus A, the Jewel Box, and 47 Tucanae. Moore compiled a list of 109 objects to match the commonly accepted number of Messier objects (he excluded M110), and the list was published in Sky & Telescope in December 1995.Moore used his other surname – Caldwell – to name the list, since the initial of "Moore" is already used for the Messier catalogue. Entries in the catalogue are designated with a "C" and the catalogue number (1 to 109).

Unlike objects in the Messier catalogue, which are listed roughly in the order of discovery by Messier and his colleagues, the Caldwell catalogue is ordered by declination, with C1 being the most northerly and C109 being the most southerly, although two objects (NGC 4244 and the Hyades) are listed out of sequence. Other errors in the original list have since been corrected: it incorrectly identified the S Norma Cluster (NGC 6087) as NGC 6067 and incorrectly labelled the Lambda Centauri Cluster (IC 2944) as the Gamma Centauri Cluster.


In chemistry, a carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula of CO2−3. The name may also refer to a carbonate ester, an organic compound containing the carbonate group C(=O)(O–)2.

The term is also used as a verb, to describe carbonation: the process of raising the concentrations of carbonate and bicarbonate ions in water to produce carbonated water and other carbonated beverages – either by the addition of carbon dioxide gas under pressure, or by dissolving carbonate or bicarbonate salts into the water.

In geology and mineralogy, the term "carbonate" can refer both to carbonate minerals and carbonate rock (which is made of chiefly carbonate minerals), and both are dominated by the carbonate ion, CO2−3. Carbonate minerals are extremely varied and ubiquitous in chemically precipitated sedimentary rock. The most common are calcite or calcium carbonate, CaCO3, the chief constituent of limestone (as well as the main component of mollusc shells and coral skeletons); dolomite, a calcium-magnesium carbonate CaMg(CO3)2; and siderite, or iron(II) carbonate, FeCO3, an important iron ore. Sodium carbonate ("soda" or "natron") and potassium carbonate ("potash") have been used since antiquity for cleaning and preservation, as well as for the manufacture of glass. Carbonates are widely used in industry, e.g. in iron smelting, as a raw material for Portland cement and lime manufacture, in the composition of ceramic glazes, and more.

Clathrate hydrate

Clathrate hydrates, or gas clathrates, gas hydrates, clathrates, hydrates, etc., are crystalline water-based solids physically resembling ice, in which small non-polar molecules (typically gases) or polar molecules with large hydrophobic moieties are trapped inside "cages" of hydrogen bonded, frozen water molecules. In other words, clathrate hydrates are clathrate compounds in which the host molecule is water and the guest molecule is typically a gas or liquid. Without the support of the trapped molecules, the lattice structure of hydrate clathrates would collapse into conventional ice crystal structure or liquid water. Most low molecular weight gases, including O2, H2, N2, CO2, CH4, H2S, Ar, Kr, and Xe, as well as some higher hydrocarbons and freons, will form hydrates at suitable temperatures and pressures. Clathrate hydrates are not officially chemical compounds, as the sequestered molecules are never bonded to the lattice. The formation and decomposition of clathrate hydrates are first order phase transitions, not chemical reactions. Their detailed formation and decomposition mechanisms on a molecular level are still not well understood.

Clathrate hydrates were first documented in 1810 by Sir Humphry Davy who found that water was a primary component of what was earlier thought to be solidified chlorine.Clathrates have been found to occur naturally in large quantities. Around 6.4 trillion (6.4×1012) tonnes of methane is trapped in deposits of methane clathrate on the deep ocean floor. Such deposits can be found on the Norwegian continental shelf in the northern headwall flank of the Storegga Slide. Clathrates can also exist as permafrost, as at the Mallik gas hydrate site in the Mackenzie Delta of northwestern Canadian Arctic. These natural gas hydrates are seen as a potentially vast energy resource, but an economical extraction method has so far proven elusive. Hydrocarbon clathrates cause problems for the petroleum industry, because they can form inside gas pipelines, often resulting in obstructions. Deep sea deposition of carbon dioxide clathrate has been proposed as a method to remove this greenhouse gas from the atmosphere and control climate change.

Clathrates are suspected to occur in large quantities on some outer planets, moons and trans-Neptunian objects, binding gas at fairly high temperatures.

Common heritage of mankind

Common heritage of mankind (also termed the common heritage of humanity, common heritage of humankind or common heritage principle) is a principle of international law that holds that defined territorial areas and elements of humanity's common heritage (cultural and natural) should be held in trust for future generations and be protected from exploitation by individual nation states or corporations.


Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).

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.

Human interactions with insects

Human interactions with insects include both a wide variety of uses, whether practical such as for food, textiles, and dyestuffs, or symbolic, as in art, music, and literature, and negative interactions including serious damage to crops and extensive efforts to eliminate insect pests.

Academically, the interaction of insects and society has been treated in part as cultural entomology, dealing mostly with "advanced" societies, and in part as ethnoentomology, dealing mostly with "primitive" societies, though the distinction is weak and not based on theory. Both academic disciplines explore the parallels, connections and influence of insects on human populations, and vice versa. They are rooted in anthropology and natural history, as well as entomology, the study of insects. Other cultural uses of insects, such as biomimicry, do not necessarily lie within these academic disciplines.

More generally, people make a wide range of uses of insects, both practical and symbolic. On the other hand, attitudes to insects are often negative, and extensive efforts are made to kill them. The widespread use of insecticides has failed to exterminate any insect pest, but has caused resistance to commonly-used chemicals in a thousand insect species.

Practical uses include as food, in medicine, for the valuable textile silk, for dyestuffs such as carmine, in science, where the fruit fly is an important model organism in genetics, and in warfare, where insects were successfully used in the Second World War to spread disease in enemy populations. One insect, the honey bee, provides honey, pollen, royal jelly, propolis and an anti-inflammatory peptide, melittin; its larvae too are eaten in some societies. Medical uses of insects include maggot therapy for wound debridement. Over a thousand protein families have been identified in the saliva of blood-feeding insects; these may provide useful drugs such as anticoagulants, vasodilators, antihistamines and anaesthetics.

Symbolic uses include roles in art, in music (with many songs featuring insects), in film, in literature, in religion, and in mythology. Insect costumes are used in theatrical productions and worn for parties and carnivals.

List of planetary nebulae

The following is an incomplete list of known planetary nebulae.

RCW Catalogue

The RCW Catalogue (from Rodgers, Campbell & Whiteoak) is an astronomical catalogue of Hα-emission regions in the southern Milky Way, described in (Rodgers et al. 1960). It contains 182 objects, including many of the earlier Gum catalogue (84 items) objects.

The later Caldwell catalogue included some objects from the RCW catalogue. There is also some overlap with the Sharpless catalogue-2 (312 items), although that primarily covered the northern hemisphere, whereas RCW and Gum primarily covered the southern hemisphere.

The RCW catalogue was compiled by Alexander William Rodgers, Colin T. Campbell and John Bartlett Whiteoak. They catalogued southern nebulae while working under Bart Bok at the Mount Stromlo Observatory in Australia in the 1960s.


Scorpius is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is (Unicode ♏). Scorpius is one of the 48 constellations identified by the Greek astronomer Ptolemy in the second century. It is an ancient constellation that pre-dated the Greeks. It lies between Libra to the west and Sagittarius to the east. It is a large constellation located in the southern hemisphere near the center of the Milky Way.

Sharpless catalog

The Sharpless catalog is a list of 313 H II regions (emission nebulae), intended to be comprehensive north of declination −27°. (It does include some nebulae south of that declination as well.) The first edition was published in 1953 with 142 objects (Sh1), and the second and final version was published by US astronomer Stewart Sharpless in 1959 with 312 objects. Sharpless also includes some planetary nebulae and supernova remnants, in addition to H II regions.In 1953 Stewart Sharpless joined the staff of the United States Naval Observatory Flagstaff Station, where he surveyed and cataloged H II regions of the Milky Way using the images from the Palomar Sky Survey. From this work Sharpless published his catalog of H II regions in two editions, the first in 1953 with 142 nebula. The second and final edition was published in 1959 with 312 nebulae.Sharpless coordinates are based on the star catalogs Bonner Durchmusterung (BD) and Cordoba Durchmusterung (CD), but the second release was adjusted to the 1900 epoch.In the second release, some coordinates for southern hemisphere regions have an uncertainty over 1 minute of arc. This can make them difficult to find, so a revised catalog called BFS (Blitz, Fich and Stark) was released. BFS has 65 new regions and about 20 removals. Most of the removed items were taken out because they were the aforementioned nebula or remnants.The 312 items in Sharpless sometimes overlap with the 110 Messier objects (M), 7,840 objects in the New General Catalogue (NGC), the Caldwell catalogue (that itself is a "best of" from other catalogues, with 109 items), and the RCW catalog. Contemporary catalogs were Gum and RCW, but they mainly covered the southern hemisphere.

See also


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