Messier 53

Messier 53 (also known as M53 or NGC 5024) is a globular cluster in the Coma Berenices constellation. It was discovered by Johann Elert Bode in 1775. M53 is one of the more outlying globular clusters, being about 60,000 light-years (18.4 kpc) light-years away from the Galactic Center, and almost the same distance (about 58,000 light-years (17.9 kpc)) from the Solar system. The cluster has a core radius (rc) of 2.18 pc, a half-light radius (rh) of 5.84 pc, and a tidal radius (rtr) of 239.9 pc.[8]

This is considered a metal-poor cluster and at one time was thought to be the most metal-poor cluster in the Milky Way.[8] Abundance measurements of cluster members on the red giant branch show that most are first-generation stars. That is, they did not form from gas recycled from previous generations of stars. This differs from the majority of globular clusters that are more dominated by second generation stars. The second generation stars in NGC 5024 tend to be more concentrated in the core region. Overall, the stellar composition of cluster members is similar to members of the Milky Way halo.[9]

The cluster displays various tidal-like features including clumps and ripples around the cluster, and tails along the cluster's orbit in an east-west direction. A tidal bridge-like structure appears to connect M53 with the close, very diffuse neighbor NGC 5053, as well as an envelope surrounding both clusters. These may indicate a dynamic tidal interaction has occurred between the two clusters; a possibly unique occurrence within the Milky Way since there are no known binary clusters within the galaxy.[10] In addition, M53 is a candidate member of the Sagittarius dwarf galaxy tidal stream.[8]

Among the variable star population in the cluster, there are 55 known to be RR Lyrae variables. Of these, a majority of 34 display behavior typical of the Blazhko effect, including 23 of type RRc – the largest known population of the latter in any globular cluster.[11] There are also at least three variables of type SX Phe and a semi-regular red giant.[12]

Messier 53
Messier 53 Hubble WikiSky
Messier 53 by Hubble Space Telescope; 3.5′ view
Credit: NASA/STScI/WikiSky
Observation data (J2000 epoch)
ClassV[1]
ConstellationComa Berenices
Right ascension 13h 12m 55.25s[2]
Declination+18° 10′ 05.4″[2]
Distance58×103 ly (18 kpc)[3]
Apparent magnitude (V)+8.33[4]
Apparent dimensions (V)13.0′[5]
Physical characteristics
Mass8.26×105[6] M
Metallicity = –1.86[7] dex
Estimated age12.67 Gyr[7]
Other designationsM53, NGC 5024, GCl 22, C 1310+184[4]
Star cluster M53 Goran Nilsson & The Liverpool Telescope
RGB image of M53 from an earthbound telescope, The Liverpool Telescope, which is a 2 m RC telescope on La Palma.

References

  1. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S.
  2. ^ a b Goldsbury, Ryan; et al. (December 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6): 1830–1837, arXiv:1008.2755, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830.
  3. ^ Hessels, J. W. T.; et al. (November 2007), "A 1.4 GHz Arecibo Survey for Pulsars in Globular Clusters", The Astrophysical Journal, 670 (1): 363–378, arXiv:0707.1602, Bibcode:2007ApJ...670..363H, doi:10.1086/521780
  4. ^ a b "NGC 5024". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 November 2006.
  5. ^ Messier 53, SEDS Messier pages
  6. ^ Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51.
  7. ^ a b Forbes, Duncan A.; Bridges, Terry (May 2010), "Accreted versus in situ Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society, 404 (3): 1203–1214, arXiv:1001.4289, Bibcode:2010MNRAS.404.1203F, doi:10.1111/j.1365-2966.2010.16373.x.
  8. ^ a b c Boberg, Owen M.; et al. (May 2015), "Chemical Abundances in NGC 5053: A Very Metal-poor and Dynamically Complex Globular Cluster", The Astrophysical Journal, 804 (2): 12, arXiv:1504.01791, Bibcode:2015ApJ...804..109B, doi:10.1088/0004-637X/804/2/109, 109.
  9. ^ Boberg, Owen M.; et al. (June 2016), "Chemical Abundances in NGC 5024 (M53): A Mostly First Generation Globular Cluster", The Astrophysical Journal, 824 (1): 15, Bibcode:2016ApJ...824....5B, doi:10.3847/0004-637X/824/1/5, 5.
  10. ^ Chun, Sang-Hyun; et al. (February 2010), "A Wide-Field Photometric Survey for Extratidal Tails Around Five Metal-Poor Globular Clusters in the Galactic Halo", The Astronomical Journal, 139 (2): 606−625, arXiv:0912.3540, Bibcode:2010AJ....139..606C, doi:10.1088/0004-6256/139/2/606
  11. ^ Arellano Ferro, A.; et al. (February 2012), "The unusually large population of Blazhko variables in the globular cluster NGC 5024 (M53)", Monthly Notices of the Royal Astronomical Society, 420 (2): 1333−1346, arXiv:1111.0216, Bibcode:2012MNRAS.420.1333A, doi:10.1111/j.1365-2966.2011.20119.x.
  12. ^ Bramich, D. M.; et al. (August 2012), "Investigation of variable star candidates in the globular cluster NGC 5024 (M53)", Monthly Notices of the Royal Astronomical Society, 424 (4): 2722−2732, arXiv:1205.5112, Bibcode:2012MNRAS.424.2722B, doi:10.1111/j.1365-2966.2012.21360.x.

External links

Coordinates: Sky map 13h 12m 55.3s, +18° 10′ 09″

1990–91 Edmonton Oilers season

The 1990–91 Edmonton Oilers season was the Oilers' 12th season in the NHL, and they were coming off of their 5th Stanley Cup in the last 7 seasons, after defeating the Boston Bruins in the Stanley Cup finals. The Oilers would finish the season with a 37–37–6 record for 80 points, their lowest point total since 1980–81, and Edmonton would score a franchise low 272 goals, however, the Oilers would set a franchise record for fewest goals against, with 272. After a 2–11–2 start to the season, the Oilers would rebound, and finish 3rd in the Smythe Division and continue their playoff streak of making the playoffs every year they've been in the NHL.

Prior to the season, long time Oiler Jari Kurri left the team due to a contract dispute signing with Italian club Milano Devils, leaving a big hole on the teams top line. Injuries would also hurt the Oilers, as Mark Messier would miss 29 games due to injuries, and his 64 points was his lowest total since 1984–85. Messier would also match the lowest goal total of his career with 12, which matched his rookie season total back in 1979–80. Esa Tikkanen would lead the club in points with 69, while Petr Klima scored a career high 40 goals to lead Edmonton in that department. Steve Smith would lead the Oilers defense with 54 points, and his 193 penalty minutes would lead the club.

In goal, Bill Ranford had a solid season, winning a team high 27 games and posting a 3.20 GAA. Grant Fuhr returned from his substance abuse suspension near the end of the season, and put together a solid 6–4–3 record with a 3.01 GAA.

In the playoffs, the Oilers would face their Battle of Alberta rivals, the Calgary Flames, who were huge favourites to win the series, as they finished with 20 more points than the Oilers did. The series went the full 7 games, with the Oilers winning the series in OT at the Saddledome in Calgary to advance to the division finals. There, they met the Los Angeles Kings, who finished 22 points better than Edmonton, however, the Oilers overtime magic continued after dropping the first game of the series, as Edmonton would win 2 games in a row in double OT to take the series lead. Edmonton would go on to win the series in 6 games, clinching the series in OT. In the Conference Finals, the Oilers would face the surprising Minnesota North Stars, who finished the season 12 games under .500, however, they defeated the Presidents Trophy winning Chicago Blackhawks and the St. Louis Blues, who finished 1 point behind Chicago, to make it to the 3rd round against Edmonton. The North Stars cinderella playoff run would continue, as they defeated the Oilers in 5 games, ending Edmonton's chance for back-to-back Stanley Cups.

They finished the regular season with the fewest short-handed goals allowed (4).

1994–95 New York Rangers season

The 1994–95 New York Rangers season was the 69th season for the franchise. The season was shortened to 48 games due to the 1994–95 NHL lockout.

For the third time in as many years, the Rangers started the season with a different head coach. Mike Keenan, who had led the team to the Stanley Cup one year earlier, left to become head coach and general manager of the St. Louis Blues under controversial circumstances. Colin Campbell was hired to replace him and the Blues sent Petr Nedved to the Rangers as compensation for Keenan, with Doug Lidster and Esa Tikkanen sent to St. Louis with their former coach.

The Rangers barely qualified for the playoffs in the shortened season, finishing one point ahead of the Florida Panthers for the last spot in the Eastern Conference. The team advanced to the second round of the playoffs, where they fell in a sweep to the Philadelphia Flyers.

Alpha Comae Berenices

Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices (Berenice's Hair), 17.8 parsecs (58 ly) away. It consists of two main sequence stars, each a little hotter and more luminous than the Sun.

Alpha Comae Berenices is said to represent the crown worn by Queen Berenice. The two components are designated Alpha Comae Berenices A (officially named Diadem , the traditional name for the system) and B.

Coma Berenices

Coma Berenices is an ancient asterism in the northern sky which has been defined as one of the 88 modern constellations. It is located in the fourth galactic quadrant, between Leo and Boötes, and is visible in both hemispheres. Its name means "Berenice's Hair" in Latin and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a votive offering. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by Gerardus Mercator and Tycho Brahe. Coma Berenices is the only modern constellation named for a historic person.

The constellation's major stars are Alpha Comae Berenices, Beta Comae Berenices and Gamma Comae Berenices. They form a 45-degree triangle, from which Berenice's imaginary tresses, formed by the Coma Star Cluster, hang. The constellation's brightest star is Beta Comae Berenices, a 4.2-magnitude main sequence star similar to the Sun. Coma Berenices contains the North Galactic Pole and one of the richest known galaxy clusters, the Coma Cluster, part of the Coma Supercluster. Galaxy Malin 1, in the constellation, is the first-known giant low-surface-brightness galaxy. Supernova SN 2005ap discovered in Coma Berenices is the second-brightest known, and SN 1940B was the first observed example of a type II supernova. The star FK Comae Berenices is the prototype of an eponymous class of variable stars. The constellation is the radiant of one meteor shower, Coma Berenicids, which has one of the fastest meteor speeds, up to 65 kilometres per second (40 mi/s).

Globular cluster

A globular cluster is a spherical collection of stars that orbit a galactic core, as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes, and relatively high stellar densities toward their centers. The name of this category of star cluster is derived from the Latin, globulus—a small sphere. A globular cluster is sometimes known, more simply, as a globular.

Globular clusters are found in the halo of a galaxy and contain considerably more stars, and are much older, than the less dense, open clusters which are found in the disk of a galaxy. Globular clusters are fairly common; there are about 150 to 158, currently known globular clusters in the Milky Way, with, perhaps, 10 to 20 more, still undiscovered. Larger galaxies can have more: The Andromeda Galaxy, for instance, may have as many as 500. Some giant elliptical galaxies (particularly those at the centers of galaxy clusters), such as M87, have as many as 13,000 globular clusters.

Every galaxy of sufficient mass in the Local Group has an associated group of globular clusters, and almost every large galaxy surveyed, has been found to possess a system of globular clusters. The Sagittarius Dwarf galaxy, and the disputed Canis Major Dwarf galaxy appear to be in the process of donating their associated globular clusters (such as Palomar 12) to the Milky Way. This demonstrates how many of this galaxy's globular clusters might have been acquired in the past.

Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their origins and their role in galactic evolution are still unclear. It does appear clear that globular clusters are significantly different from dwarf elliptical galaxies and were formed as part of the star formation of the parent galaxy, rather than as a separate galaxy.

List of Edmonton Oilers records

This is a list of franchise records for the Edmonton Oilers of the National Hockey League.

List of NGC objects (5001–6000)

This is a list of NGC objects 5001–6000 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.

M53

M53, M-53, or M.53 may refer to:

M53 155mm Self-Propelled Gun, an American-made tracked, self-propelled gun

M53, a Hungarian submachine gun developed from the Soviet PPS-43 submachine gun; see PPS submachine gun#Variants

M-53 (Michigan highway), a state highway in Eastern Michigan

M53 highway (Russia), a section of the Baikal Highway in Siberia

M53 motorway, a motorway in England

Macchi M.53, an Italian military reconnaissance floatplane of 1928

Messier 53, a globular cluster in the constellation Coma Berenices

Snecma M53, a French afterburning turbofan engine developed for the Dassault Mirage 2000 fighter

M53, Yugoslav copy of MG42

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.

NGC 5053

NGC 5053 is the New General Catalogue designation for a globular cluster in the northern constellation of Coma Berenices. It was discovered by German-British astronomer William Herschel on March 14, 1784 and cataloged as VI-7. In his abbreviated notation, he described it as, "an extremely faint cluster of extremely small stars with resolvable nebula 8 or 10′ diameter, verified by a power of 240, beyond doubt". Danish-Irish astronomer John Louis Emil Dreyer reported in 1888 that the cluster appeared, "very faint, pretty large, irregular round shape, growing very gradually brighter at the middle".This is a metal-poor cluster, meaning the stars have a low abundance of elements other than hydrogen and helium—what astronomers term metallicity. As recently as 1995, it was considered the most metal-poor globular cluster in the Milky Way. The chemical abundances of the stars in NGC 5053 are more similar to those in the dwarf galaxy Sagittarius Dwarf Spheroidal Galaxy than to the Milky Way halo. Along with the kinematics of the globular cluster, this suggests that NGC 5053 may have been stripped from the dwarf galaxy.There are ten known RR Lyrae variable stars in this cluster with masses ranging from 68% to 78% of the solar mass. Nine of these variables were reported by German astronomer Walter Baade in 1928, and the tenth by American astronomer Helen Sawyer in 1946. The cluster hosts 27 known blue stragglers, of which five are short period SX Phoenicis variable stars.NGC 5053 is a relatively low mass cluster with a low core concentration factor of 1.32. It sports a stream of tidal debris to the west with a projected length of 1.7 kpc. This stream may have been created through shock-induced processes. The cluster is located less than 1° from Messier 53 and the two have nearly the same distance modulus, which corresponds to a spatial separation of around 2 kpc. There is a tidal bridge joining M53 to NGC 5053, suggesting the pair may have interacted in the past. The cluster is following an orbit through the Milky Way that has a perigalacticon distance of 9 kpc and an orbital eccentricity of 0.84. At present, it is 18.4 kpc from the Galactic Core, with a radial velocity of 42.0±1.4 km/s.

Timeline of epochs in cosmology

The timeline of cosmological epochs outlines the formation and subsequent evolution of the Universe from the Big Bang (13.799 ± 0.021 billion years ago) to the present day. An epoch is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new era or age.

Times on this list are measured from the moment of the Big Bang.

List
See also
Messier
NGC

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