Messier 7

Messier 7 or M7, also designated NGC 6475 and sometimes known as the Ptolemy Cluster,[4] is an open cluster of stars in the constellation of Scorpius. The cluster is easily detectable with the naked eye, close to the "stinger" of Scorpius. With a declination of -34.8°, it is the southernmost Messier object.

M7 has been known since antiquity; it was first recorded by the 2nd-century Greek-Roman astronomer Ptolemy, who described it as a nebula in 130 AD.[5] Italian astronomer Giovanni Batista Hodierna observed it before 1654 and counted 30 stars in it. In 1764, French astronomer Charles Messier catalogued the cluster as the seventh member in his list of comet-like objects. English astronomer John Herschel described it as "coarsely scattered clusters of stars".[4]

Open-cluster-Messier-7.jpeg
Broader view of M7, the cluster is at the center of this photograph.
The star cluster Messier 7
The star cluster Messier 7

Telescopic observations of the cluster reveal about 80 stars within a field of view of 1.3° across. At the cluster's estimated distance of 980 light years this corresponds to an actual diameter of 25 light years. The tidal radius of the cluster is 40.1 ly (12.3 pc) and it has a combined mass of about 735 times the mass of the Sun.[3] The age of the cluster is around 200[2] million years while the brightest member star is of magnitude 5.6. In terms of composition, the cluster contains a similar abundance of elements other than hydrogen and helium as the Sun.[2]

On Aug. 29, 2006, Messier 7 was used for first light image of the Long Range Reconnaissance Imager (LORRI) telescope on the Pluto-bound New Horizons spacecraft.[6]

Messier 7
Messier7
Observation data (J2000.0 epoch)
ConstellationScorpius
Right ascension 17h 53m 51.2s[1]
Declination–34° 47′ 34″[1]
Distance980 ± 33 ly (300 ± 10 pc)[2]
Apparent magnitude (V)3.3
Apparent dimensions (V)80.0′
Physical characteristics
Mass735[3] M
Radius25 ly
Estimated age200 Myr[2]
Other designationsM7, NGC 6475, Ptolemy Cluster

See also

References

  1. ^ a b "MESSIER 007", NASA/IPAC Extragalactic Database, NASA, retrieved 2012-04-19
  2. ^ a b c d Villanova, S.; Carraro, G.; Saviane, I. (September 2009), "A spectroscopic study of the open cluster NGC 6475 (M 7). Chemical abundances from stars in the range Teff = 4500-10 000 K", Astronomy and Astrophysics, 504 (3): 845–852, arXiv:0906.4330, Bibcode:2009A&A...504..845V, doi:10.1051/0004-6361/200811507
  3. ^ a b Piskunov, A. E.; et al. (January 2008), "Tidal radii and masses of open clusters", Astronomy and Astrophysics, 477 (1): 165–172, Bibcode:2008A&A...477..165P, doi:10.1051/0004-6361:20078525
  4. ^ a b Gendler, Robert; Christensen, Lars Lindberg; Malin, David (2011), Treasures of the Southern Sky: A Photographic Anthology, Springer, p. 139, ISBN 978-1461406273
  5. ^ Jones, Kenneth Glyn (1991), Messier's Nebulae and Star Clusters, The Practical astronomy handbook series (2) (2ns ed.), Cambridge University Press, p. 1, ISBN 978-0521370790
  6. ^ "LORRI's First Light1". pluto.jhuapl.edu. Retrieved 2018-10-24.

External links

Coordinates: Sky map 17h 53.9m 00s, −34° 49′ 00″

132524 APL

132524 APL, provisional designation 2002 JF56, is a small background asteroid in the intermediate asteroid belt. It was discovered by LINEAR in May 2002, and imaged by the New Horizons space probe on its flyby in June 2006, when it was passing through the asteroid belt. The stony S-type asteroid measures approximately 2.5 kilometers (1.6 miles) in diameter.

1984 Stanley Cup Finals

The 1984 Stanley Cup Finals was the championship series of the National Hockey League's (NHL) 1983–84 season, and the culmination of the 1984 Stanley Cup playoffs. It was contested between the Edmonton Oilers and the defending champion New York Islanders. The upstart Oilers won the best-of-seven series, four games to one, to win their first Stanley Cup, becoming the third post-1967 expansion team and first former World Hockey Association team to win the Cup, and also the first team based west of Chicago to win the Cup since the WCHL's Victoria Cougars became the last non-NHL team to win it in 1925.

In the previous year's Stanley Cup Finals, the Islanders had swept the Oilers in four straight games. The teams rematched in 1984, with the Islanders seeking their fifth consecutive Stanley Cup championship. It was the fifth straight Finals of teams that joined the NHL in 1967 or later. As of 2017, the Islanders' four consecutive Cup wins (1980, 1981, 1982, 1983) and their appearance in the 1984 Cup Finals is an NHL record of 19 consecutive playoff series wins that currently stands unbroken. The 1984 Finals was the second of eight consecutive Finals contested by a team from Alberta (the Oilers appeared in six, the Calgary Flames in two), and the first of five consecutive Finals to end with the Cup presentation on Alberta ice (the Oilers won four times, the Montreal Canadiens one).

The Oilers became the fastest-ever Canadian-based expansion team to win a major sports title by winning a title in only their fifth NHL season. The feat would be eclipsed in 2016 by the Ottawa Redblacks, who won the Grey Cup in their third CFL season.

1988–89 Edmonton Oilers season

The 1988–89 Edmonton Oilers season was the Oilers' tenth season in the NHL, and they were coming off a Stanley Cup championship after defeating the Boston Bruins the previous season, which was their fourth Stanley Cup in the past 5 seasons. The Oilers would finish third in the Smythe Division with 84 points, their lowest point total since the 1980–81 season. For the eighth consecutive season, the Oilers had five 30-goal scorers.

Prior to the season, the Oilers would be involved in one of the biggest trades in NHL history, dealing Wayne Gretzky, Marty McSorley and Mike Krushelnyski to the Los Angeles Kings in exchange for Jimmy Carson, Martin Gelinas, the Kings first round draft picks in 1989, 1991 and 1993, and $15 million.

Jari Kurri would lead the club with 102 points, while Jimmy Carson would score a team high 49 goals, and Mark Messier would have a team best 61 assists. Charlie Huddy would lead the defense with 44 points, while Kelly Buchberger would provide the team toughness, leading the Oilers with 234 penalty minutes.

In goal, Grant Fuhr would get the majority of the starts, leading the team with 23 wins, while Bill Ranford would have a team best 3.50 GAA.

The Oilers finished the regular season first in short-handed goals scored, with 27.In the playoffs, the Oilers would face Wayne Gretzky and the Los Angeles Kings in the opening round of the playoffs. The Oilers would take a 3–1 series lead, however, the Kings would respond by winning 3 games in a row by a combined score of 16–6 to win the series, ending the Oilers bid at winning a third straight Stanley Cup and for the first time since 1982, Edmonton would fail to win a playoff round.

Butterfly Cluster

The Butterfly Cluster (cataloged as Messier 6 or M6, and as NGC 6405) is an open cluster of stars in the southern constellation of Scorpius. Its name derives from the vague resemblance of its shape to a butterfly. The Trumpler classification of II 3 r indicates it is rich in stars (r) with a high concentration (II) and a large range of brightness (3). It is positioned 3.5° to the northwest of Messier 7 near the tail of Scorpius.The first astronomer to record the Butterfly Cluster's existence was Giovanni Battista Hodierna in 1654. However, Robert Burnham, Jr. has proposed that the 1st century astronomer Ptolemy may have seen it with the naked eye while observing its neighbor the Ptolemy Cluster (M7). Credit for the discovery is usually given to Jean-Philippe Loys de Chéseaux in 1746. Charles Messier observed the cluster on May 23, 1764 and added it to his Messier Catalog.Estimates of the Butterfly Cluster's distance have varied over the years. Wu et al. (2009) found a distance estimate of 1,590 light-years, giving it a spatial dimension of some 12 light years. Modern measurements show its total visual brightness to be magnitude 4.2. The cluster is estimated to be 94.2 million years old. Cluster members show a slightly higher abundance of elements heavier than helium compared to the Sun; what astronomers refer to as the metallicity.

120 stars, ranging down to visual magnitude 15.1, have been identified as most likely cluster members. Most of the bright stars in this cluster are hot, blue B-type stars but the brightest member is a K-type orange giant star, BM Scorpii, which contrasts sharply with its blue neighbours in photographs. BM Scorpii, is classed as a semiregular variable star, its brightness varying from magnitude +5.5 to magnitude +7.0. There are also eight candidate chemically peculiar stars.The cluster is located 24.59 ± 0.13 kly (7.54 ± 0.04 kpc) from the Galactic Center and is following an orbit through the Milky Way galaxy with a low eccentricity of 0.03 and an orbital period of 204.2 Myr. At present it is 23 ly (7 pc) below the galactic plane, and it will cross the plane every 29.4 Myr.

List of NGC objects (6001–7000)

This is a list of NGC objects 6001–7000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of NGC objects.

The constellation information in these tables is taken from The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer, which was accessed using the "VizieR Service". Galaxy types are identified using the NASA/IPAC Extragalactic Database. The other data of these tables are from the SIMBAD Astronomical Database unless otherwise stated.

List of astronomical objects named after people

There are probably a few thousand astronomical objects named after people. These include the names of a few thousand asteroids and hundreds of comets. Also, many topological features on solar system bodies have been named after people, including many hundreds of craters on the Moon, Mars and other planets and satellites. In addition to craters there are also various other topological features such as mountains, valleys, ridges on the Moon and other bodies which are also named after people. Finally, several stars are named after people (according to the IAU), such as Barnard's star (Star-registry companies keep lists of stars they claim to have named after people. The IAU does not recognize those claims.). There's also a number of Deep-Sky objects named after astronomers and scientists. The list below shows most of them.

List of open clusters

This is a list of open clusters located in the Milky Way. An open cluster is a gravitationally bound association of up to a few thousand stars that all formed from the same giant molecular cloud. There are over 1,000 known open clusters in the Milky Way galaxy, but the actual total may be up to ten times higher. The estimated half lives of clusters, after which half the original cluster members will have been lost, range from 150 million to 800 million years, depending on the original density.

List of stars in Scorpius

This is the list of notable stars in the constellation Scorpius, sorted by decreasing brightness.

Long Range Reconnaissance Imager

Long Range Reconnaissance Imager (LORRI) is a telescope aboard the New Horizons spacecraft for imaging. LORRI has been used to image Jupiter and its moons and especially Pluto and its system of moons since its launched in 2006. LORRI is a reflecting telescope of Ritchey-Chrétien design, and it has a main mirror diameter of 20.8 cm (8.2 inches) across. Images are taken with a CCD capturing data with 1024 × 1024 pixels. LORRI is a telescopic panchromatic imager integrated with the New Horizons spacecraft, and it is one of seven major science instruments on the probe. LORRI does not have any moving parts and is pointed by moving the entire New Horizons spacecraft. LORRI has a narrow field of view, less than a third of one degree.

MPG/ESO telescope

The MPG/ESO telescope is a 2.2-metre f/8.0 (17.6-metre) ground-based telescope at the European Southern Observatory (ESO) in La Silla, Chile. It was built by Zeiss and has been operating since 1984. It was on indefinite loan to the European Southern Observatory from the Max Planck Institute for Astronomy (MPIA). In October 2013 it was returned to the MPIA. Telescope time is shared between MPIA and MPE observing programmes, while the operation and maintenance of the telescope are ESO's responsibility.The telescope hosts three instruments: the 67-million-pixel Wide Field Imager with a field of view as large as the full Moon, which has taken many amazing images of celestial objects; GROND, the Gamma-Ray Burst Optical/Near-Infrared Detector, which chases the afterglows of the most powerful explosions in the universe, known as gamma-ray bursts; and the high-resolution spectrograph, FEROS, used to make detailed studies of stars.In November 2010 it was used to discover HIP 13044 b, marking the first time a planetary system in a stellar stream of extragalactic origin has been detected.

Messier object

The Messier objects are a set of 110 astronomical objects cataloged by the French astronomer Charles Messier in his Catalogue des Nébuleuses et des Amas d'Étoiles ("Catalogue of Nebulae and Star Clusters").

Because Messier was interested in finding only comets, he created a list of non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as the Messier catalogue. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier number.

The catalogue includes some astronomical objects that can be observed from Earth's Northern Hemisphere such as deep-sky objects, a characteristic which makes the Messier objects extremely popular targets for amateur astronomers.A preliminary version first appeared in the Memoirs of the French Academy of Sciences in 1771,

and the last item was added in 1966 by Kenneth Glyn Jones, based on Messier's observations.

The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. In addition to his own discoveries, this version included objects previously observed by other astronomers, with only 17 of the 45 objects being Messier's.

By 1780 the catalogue had increased to 80 objects. The final version of the catalogue containing 103 objects was published in 1781 in the Connaissance des Temps for the year 1784.

However, due to what was thought for a long time to be the incorrect addition of Messier 102, the total number remained 102. Other astronomers, using side notes in Messier's texts, eventually filled out the list up to 110 objects.The catalogue consists of a diverse range of astronomical objects, ranging from star clusters and nebulae to galaxies. For example, Messier 1 is a supernova remnant, known as the Crab Nebula, and the great spiral Andromeda Galaxy is M31. Many further inclusions followed in the next century when the first addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier's side note in his 1781 edition exemplar of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967.

Naked eye

Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying or light-collecting optical instrument, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is still considered "naked".

In astronomy, the naked eye may be used to observe celestial events and objects visible without equipment, such as conjunctions, passing comets, meteor showers, and the brightest asteroids, including 4 Vesta. Sky lore and various tests demonstrate an impressive variety of phenomena visible to the unaided eye.

Ptolemy

Claudius Ptolemy (; Koinē Greek: Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos [kláwdios ptolɛmɛ́os]; Latin: Claudius Ptolemaeus; c. AD 100 – c.  170) was a mathematician, astronomer, geographer and astrologer. He lived in the city of Alexandria in the Roman province of Egypt, under the rule of the Roman Empire, had a Latin name, which several historians have taken to imply he was also a Roman citizen,, cited Greek philosophers, and used Babylonian observations and Babylonian lunar theory. The 14th-century astronomer Theodore Meliteniotes gave his birthplace as the prominent Greek city Ptolemais Hermiou (Greek: Πτολεμαΐς ‘Ερμείου) in the Thebaid (Greek: Θηβαΐδα [Θηβαΐς]). This attestation is quite late, however, and there is no other evidence to confirm or contradict it. He died in Alexandria around AD 168.Ptolemy wrote several scientific treatises, three of which were of importance to later Byzantine, Islamic and Western European science. The first is the astronomical treatise now known as the Almagest, although it was originally entitled the Mathematical Treatise (Μαθηματικὴ Σύνταξις, Mathēmatikē Syntaxis) and then known as the Great Treatise (Ἡ Μεγάλη Σύνταξις, Hē Megálē Syntaxis). The second is the Geography, which is a thorough discussion of the geographic knowledge of the Greco-Roman world. The third is the astrological treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika (Ἀποτελεσματικά) but more commonly known as the Tetrabiblos from the Greek (Τετράβιβλος) meaning "Four Books" or by the Latin Quadripartitum.

Risa Horowitz

Risa Horowitz (born 1970) is a Canadian visual and media artist. Her works have been exhibited across Canada and internationally. Her work has been shown at Canada House in London, England, and is included in its permanent collection. She is currently an associate professor at the University of Regina, Saskatchewan, Canada.

Scorpius

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.

Stars named after people

Over the past few centuries, a small number of stars have been named after individual people. It is common in astronomy for objects to be given names, in accordance with accepted astronomical naming conventions. Most stars have not been given proper names, relying instead on alphanumeric designations in star catalogues. However, a few hundred had either long-standing traditional names (usually from the Arabic) or historic names from frequent usage.

In addition, many stars have catalogue designations that contain the name of their compiler or discoverer. This includes Wolf, Ross, Bradley, Piazzi, Lacaille, Struve, Groombridge, Lalande, Krueger, Mayer, Weisse, Gould, Luyten and others. For example, Wolf 359, discovered and catalogued by Max Wolf.

Telescopium

Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.

The brightest star in the constellation is Alpha Telescopii, a blue-white subgiant with an apparent magnitude of 3.5, followed by the orange giant star Zeta Telescopii at magnitude 4.1. Eta and PZ Telescopii are two young star systems with debris disks and brown dwarf companions. Telescopium hosts two unusual stars with very little hydrogen that are likely to be the result of two merged white dwarfs: PV Telescopii, also known as HD 168476, is a hot blue extreme helium star, while RS Telescopii is an R Coronae Borealis variable. RR Telescopii is a cataclysmic variable that brightened as a nova to magnitude 6 in 1948.

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See also

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