Messier 93

Last updated
Messier 93
M93 Eguivar.jpg
Open cluster Messier 93 in Puppis
Observation data (J2000.0 epoch)
Constellation Puppis
Right ascension 07h 44m 30.0s [1]
Declination −23° 51 24 [1]
Distance 3.38  kly (1.037  kpc) [1]
Apparent magnitude (V)6.0 [2]
Apparent dimensions (V)10′ [3]
Physical characteristics
Mass723 [4]   M
Radius5 [3]
Estimated age387.3 Myr [1]
Other designations NGC 2447, Cr 160, OCl 649.0 [5]
See also: Open cluster, List of open clusters

Messier 93 or M93, also known as NGC 2447, is an open cluster in the modestly southern constellation Puppis, the imagined poop deck of the legendary Argo .

Contents

Observational history and appearance

It was discovered by Charles Messier then added to his catalogue of comet-like objects in 1781. [lower-alpha 1] [6] Caroline Herschel, the younger sister of William Herschel, independently discovered it in 1783, thinking it had not yet been catalogued by Messier. [7]

Walter Scott Houston (died 1993) described its appearance: [8]

Some observers mention the cluster as having the shape of a starfish. With a fair-sized telescope, this is its appearance on a dull night, but [a four-inch refractor] shows it as a typical star-studded galactic cluster.

Properties

It has a Trumpler class of I 3 r, indicating it is strongly concentrated (I) with a large range in brightness (3) and is rich in stars (r). [9]

M93 is about 3,380 [1] light-years from the solar radius and has a great spatial radius of 5 light-years, [3] a tidal radius of 13.1±2.3 ly, [4] and a core radius of 4.2 ly. [10] Its age is estimated at 387.3 million years. [1] It is nearly on the galactic plane and has an orbit that varies between 28–29 kly (8.5–8.9 kpc) from the Galactic Center over a period of 242.7±7.9 Myr. [1]

Fifty-four variable stars have been found in M93, including one slowly pulsating B-type star, one rotating ellipsoidal variable, seven Delta Scuti variables, six Gamma Doradus variables, and one hybrid δ [lower-alpha 2] Sct/γ Dor [lower-alpha 3] pulsator. [11] Four spectroscopic binary systems within include a yellow straggler component. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Butterfly Cluster</span> Open cluster in Scorpius

The Butterfly Cluster 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 encodes it is rich in stars, ranks II out of IV for disparateness and greatly mixes bright with faint components. It is 3.5° to the northwest of Messier 7, both north of the tail of Scorpius.

<span class="mw-page-title-main">Wild Duck Cluster</span> Open cluster in the constellation Scutum

The Wild Duck Cluster is an open cluster of stars in the constellation Scutum. It was discovered by Gottfried Kirch in 1681. Charles Messier included it in his catalogue of diffuse objects in 1764. Its popular name derives from the brighter stars forming a triangle which could resemble a flying flock of ducks. The cluster is located just to the east of the Scutum Star Cloud midpoint.

<span class="mw-page-title-main">Messier 21</span> Open cluster in the constellation Sagittarius

Messier 21 or M21, also designated NGC 6531 or Webb's Cross, is an open cluster of stars located to the north-east of Sagittarius in the night sky, close to the Messier objects M20 to M25. It was discovered and catalogued by Charles Messier on June 5, 1764. This cluster is relatively young and tightly packed. A few blue giant stars have been identified in the cluster, but Messier 21 is composed mainly of small dim stars. With a magnitude of 6.5, M21 is not visible to the naked eye; however, with the smallest binoculars it can be easily spotted on a dark night. The cluster is positioned near the Trifid nebula, but is not associated with that nebulosity. It forms part of the Sagittarius OB1 association.

<span class="mw-page-title-main">Messier 23</span> Open cluster in Sagittarius

Messier 23, also known as NGC 6494, is an open cluster of stars in the northwest of the southern constellation of Sagittarius. It was discovered by Charles Messier in 1764. It can be found in good conditions with binoculars or a modestly sized telescope. It is in front of "an extensive gas and dust network", which there may be no inter-association. It is within 5° the sun's position so can be occulted by the moon.

<span class="mw-page-title-main">Messier 25</span> Open cluster in Sagittarius

Messier 25, also known as IC 4725, is an open cluster of stars in the southern constellation of Sagittarius. The first recorded observation of this cluster was made by Philippe Loys de Chéseaux in 1745 and it was included in Charles Messier's list of nebulous objects in 1764. The cluster is located near some obscuring features, with a dark lane passing near the center.

<span class="mw-page-title-main">Messier 26</span> Open cluster in the constellation Scutum

Messier 26, also known as NGC 6694, is an open cluster of stars in the southern constellation of Scutum. It was discovered by Charles Messier in 1764. This 8th magnitude cluster is a challenge to find in ideal skies with typical binoculars, where it can be, with any modern minimum 3-inch (76 mm) aperture device. It is south-southwest of the open cluster Messier 11 and is 14′ across. About 25 stars are visible in a telescope with a 150–200 mm (6–8 in) aperture.

<span class="mw-page-title-main">Messier 18</span> Open cluster in the constellation Sagittarius

Messier 18 or M18, also designated NGC 6613, is an open cluster of stars in the constellation Sagittarius. It was discovered by Charles Messier in 1764 and included in his list of comet-like objects. From the perspective of Earth, M18 is situated between the Omega Nebula (M17) and the Small Sagittarius Star Cloud (M24).

<span class="mw-page-title-main">Messier 36</span> Open cluster in the constellation Auriga

Messier 36 or M36, also known as NGC 1960, is an open cluster of stars in the somewhat northern Auriga constellation. It was discovered by Giovanni Batista Hodierna before 1654, who described it as a nebulous patch. The cluster was independently re-discovered by Guillaume Le Gentil in 1749, then Charles Messier observed it in 1764 and added it to his catalogue. It is about 1,330 pc away from Earth. The cluster is very similar to the Pleiades cluster (M45), and if as far away it would be of similar apparent magnitude.

<span class="mw-page-title-main">Messier 37</span> Open cluster in the constellation Auriga

Messier 37 is the brightest and richest open cluster in the constellation Auriga. It was discovered by the Italian astronomer Giovanni Battista Hodierna before 1654. M37 was missed by French astronomer Guillaume Le Gentil when he rediscovered M36 and M38 in 1749. French astronomer Charles Messier independently rediscovered M37 in September 1764 but all three of these clusters were recorded by Hodierna. It is classified as Trumpler type I,1,r or I,2,r.

<span class="mw-page-title-main">Messier 39</span> Open cluster in the constellation Cygnus

Messier 39 or M39, also known as NGC 7092, is an open cluster of stars in the constellation of Cygnus, positioned two degrees to the south of the star Pi Cygni and around 9° east-northeast of Deneb. The cluster was discovered by Guillaume Le Gentil in 1749, then Charles Messier added it to his catalogue in 1764. When observed in a small telescope at low power the cluster shows around two dozen members but is best observed with binoculars. It has a total integrated magnitude (brightness) of 5.5 and spans an angular diameter of 29 arcminutes – about the size of the full Moon. It is centered about 1,010 light-years away.

<span class="mw-page-title-main">Messier 46</span> Open cluster in the constellation Puppis

Messier 46 or M46, also known as NGC 2437, is an open cluster of stars in the slightly southern constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." It is about 5,000 light-years away. There are an estimated 500 stars in the cluster with a combined mass of 453 M, and it is thought to be a mid-range estimate of 251.2 million years old.

<span class="mw-page-title-main">Messier 48</span> Open cluster in the constellation Hydra

Messier 48 or M48, also known as NGC 2548, is an open cluster of stars in the equatorial constellation of Hydra. It sits near Hydra's westernmost limit with Monoceros, about 18° 34′ to the east and slightly south of Hydra's brightest star, Alphard. This grouping was discovered by Charles Messier in 1771, but there is no cluster precisely where Messier indicated; he made an error, as he did with M47. The value that he gave for the right ascension matches, however, his declination is off by five degrees. Credit for discovery is sometimes given instead to Caroline Herschel in 1783. Her nephew John Herschel described it as, "a superb cluster which fills the whole field; stars of 9th and 10th to the 13th magnitude – and none below, but the whole ground of the sky on which it stands is singularly dotted over with infinitely minute points".

<span class="mw-page-title-main">Messier 52</span> Open cluster in the constellation Cassiopeia

Messier 52 or M52, also known as NGC 7654, is an open cluster of stars in the highly northern constellation of Cassiopeia. It was discovered by Charles Messier on 1774. It can be seen from Earth under a good night sky with binoculars. The brightness of the cluster is influenced by extinction, which is stronger in the southern half. Its metallicity is somewhat below that of the Sun, and is estimated to be [Fe/H] = −0.05 ± 0.01.

<span class="mw-page-title-main">NGC 2506</span> Open cluster in the constellation Monoceros

NGC 2506 is a mildly-elongated open cluster of stars in the equatorial constellation of Monoceros, located at a distance of 12.7 kly from the Sun near the Galactic anti-center. It was discovered by William Herschel in 1791. The cluster lies around 10,000 ly from the Galactic Center and about 1,600 ly above the Galactic plane. It is of intermediate age, estimated at around two billion years. The cluster has an angular radius of 12′ and a core radius of 4.8′.

<span class="mw-page-title-main">NGC 637</span> Open star cluster in the constellation Cassiopeia

NGC 637 is an open cluster of stars in the northern constellation of Cassiopeia, positioned about 1.5° to the WNW of the star Epsilon Cassiopeiae. The cluster was discovered on 9 November 1787 by German-born English astronomer William Herschel. It is located in the Perseus Arm of the Milky Way, at a distance of approximately 7.045 kilolight-years from the Sun. The cluster is small but compact, and is readily visible in a small telescope.

<span class="mw-page-title-main">NGC 1817</span> Open cluster in the constellation Taurus

NGC 1817 is an open cluster of stars in the constellation Taurus. It was discovered by English astronomer William Herschel in February 1784. With an apparent magnitude of 7.7 and spanning 9.3 arc minutes across the sky, it is separated from the NGC 1807 cluster by just 26 arc minutes. Indeed, the two may actually be parts of a single extended cluster.

<span class="mw-page-title-main">NGC 2539</span> Open cluster in the constellation Puppis

NGC 2539 is an open cluster in the constellation Puppis, located at the north edge of the constellation. It was discovered by William Herschel on January 31, 1785. It is a moderately rich cluster and with little central concentration, with Trumpler class II1m.

NGC 5662 is an open cluster in the constellation Centaurus. It was discovered by Nicolas Louis de Lacaille on May 17, 1752 from South Africa. James Dunlop observed it on July 10, 1826 from Parramatta, Australia and added it to his catalog as No. 342.

<span class="mw-page-title-main">NGC 5617</span> Open cluster in the constellation Centaurus

NGC 5617 is an open cluster in the constellation Centaurus. NGC 5617 forms a binary open cluster with Trumpler 22. It lies one degree west-northwest of Alpha Centauri.

<span class="mw-page-title-main">NGC 4349</span> Open cluster in the constellation Crux

NGC 4349 is an open cluster in the constellation Crux. It was discovered by James Dunlop in 1826. It is located approximately 7,000 light years away from Earth.

References

  1. 1 2 3 4 5 6 7 Wu, Zhen-Yu; et al. (November 2009), "The orbits of open clusters in the Galaxy", Monthly Notices of the Royal Astronomical Society , 399 (4): 2146–2164, arXiv: 0909.3737 , Bibcode:2009MNRAS.399.2146W, doi:10.1111/j.1365-2966.2009.15416.x, S2CID   6066790.
  2. "Messier 93". SEDS Messier Catalog. Retrieved 30 April 2022.
  3. 1 2 3 Finlay, Warren H. (2014), Concise Catalog of Deep-Sky Objects: Astrophysical Information for 550 Galaxies, Clusters and Nebulae, The Patrick Moore Practical Astronomy Series (2nd ed.), Springer, p. 120, ISBN   978-3319031705
  4. 1 2 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 .
  5. "NGC 2447". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-12-06.
  6. Frommert, Hartmut; Kronberg, Christine (September 2, 2007), "Messier 93", SEDS Messier pages, Students for the Exploration and Development of Space (SEDS), retrieved 2018-12-07.
  7. Hoskin, Michael (February 1, 2016), "Gazing at the starry heavens", Astronomy & Geophysics, 57 (1): 1.22–1.25, Bibcode:2016A&G....57a1.22H, doi: 10.1093/astrogeo/atw038
  8. Houston, Walter Scott (2005). Deep-Sky Wonders. Sky Publishing Corporation. ISBN   978-1-931559-23-2.
  9. Maitzen, H. M. (November 1993), "Photoelectric Search for Peculiar Stars in Open Clusters - Part Fourteen - NGC1901 NGC2169 NGC2343 CR:132 NGC2423 and NGC2447", Astronomy and Astrophysics Supplement, 102 (1): 1, Bibcode:1993A&AS..102....1M.
  10. Piskunov, A. E.; et al. (June 2007), "Towards absolute scales for the radii and masses of open clusters", Astronomy and Astrophysics, 468 (1): 151–161, arXiv: astro-ph/0702517 , Bibcode:2007A&A...468..151P, doi:10.1051/0004-6361:20077073, S2CID   14769639.
  11. Eyer, L.; Eggenberger, P.; Greco, C.; Saesen, S.; Anderson, R. I.; Mowlavi, N. (September 2010), "Time resolved surveys of stellar clusters", JENAM 2010, Joint European and National Astronomy Meeting held 6-10 September, 2010 in Lisbon Portugal, p. 212, arXiv: 1011.4952 , Bibcode:2010jena.confE.212E, 212.
  12. da Silveira, M. D.; et al. (June 2018), "Red giants and yellow stragglers in the young open cluster NGC 2447", Monthly Notices of the Royal Astronomical Society, 476 (4): 4907–4931, Bibcode:2018MNRAS.476.4907D, doi:10.1093/mnras/sty265
  1. On March 20
  2. Delta Scuti
  3. Gamma Doradus