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Perseus is a constellation in the northern sky, named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage.
Xi Scorpii is part of a quintuple star system in the constellation Scorpius. It was assigned this designation by Bayer, although Ptolemy had catalogued the star in Libra. Flamsteed assigned it the designation 51 Librae, but this has fallen out of use since modern constellation boundaries assign the star to Scorpius.
Sh 2-279 is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion. It is the northernmost part of the asterism known as Orion's Sword, lying 0.6° north of the Orion Nebula. The reflection nebula embedded in Sh 2-279 is popularly known as the Running Man Nebula.
4 Centauri is a star in the constellation Centaurus. It is a blue-white B-type subgiant with an apparent magnitude of +4.75 and is approximately 640 light years from Earth.
NGC 1555, sometimes known as Hind's Variable Nebula, Sh2-238 or HH 155, is a variable nebula 4 light years across, illuminated by the star T Tauri, located in the constellation Taurus. It is 400 light years away from Earth, and has a magnitude (B) of 9.98. It is also in the second Sharpless catalog as 238. It is a Herbig–Haro object. The nebula was discovered on October 11, 1852, by John Russell Hind.
Sh 2-155 is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh 2-155 is an ionized H II region with ongoing star formation activity, at an estimated distance of 725 parsecs from Earth.
Sharpless 101 (Sh 2-101) is a H II region emission nebula located in the constellation Cygnus. It is sometimes also called the Tulip Nebula because it appears to resemble the outline of a tulip when imaged photographically. It was catalogued by astronomer Stewart Sharpless in his 1959 catalog of nebulae. It lies at a distance of about 6,000 light-years (5.7×1016 km; 3.5×1016 mi) from Earth.
NGC 6820 is a small reflection nebula near the open cluster NGC 6823 in Vulpecula. The reflection nebula and cluster are embedded in a large faint emission nebula called Sh 2-86. The whole area of nebulosity is often referred to as NGC 6820.
Chi Lupi is a spectroscopic binary star in the constellation of Lupus. It has an apparent visual magnitude of approximately 3.957. The primary star in the binary is a mercury-manganese star of spectral type B9.5V; the secondary is a metallic-lined star of type A2Vm.
NGC 1931 is an emission and reflection nebula in the constellation Auriga. The nebula has been referred to as a "miniature version of the Orion Nebula", as it shares some of the same characteristics. It is a mixed emission-reflection nebula, and contains a smaller version of the Trapezium in its hot young star cluster centered in the emission nebula. The entire cluster/nebula complex is only about 3 arcmin in size. The distance from earth is estimated at 7000 light years.
Simeis 147, also known as the Spaghetti Nebula, SNR G180.0-01.7 or Sharpless 2-240, is a supernova remnant (SNR) in the Milky Way, straddling the border between the constellations Auriga and Taurus. It was discovered in 1952 at the Crimean Astrophysical Observatory by Grigory Shajn and his team using a Schmidt camera and a narrowband filter close to the Hydrogen Alpha transmission line. It is difficult to observe due to its extremely low surface brightness. This discovery was part of a survey conducted between 1945 and 1955, most likely using captured German equipment, as the observatory was practically destroyed during WWII. The Schmidt camera had a field of view of 175'. Many previously unknown hydrogen nebula were discovered this way, as they are not readily visible in regular photographs.
Sh 2-54 is an extended bright nebula in the constellation of Serpens.
H Centauri, also known as V945 Centauri, is probable triple star system located in the constellation Centaurus. From parallax measurements, it is located 113 parsecs from the Sun. It is a member of the Lower Centaurus–Crux (LCC) subgroup of the Scorpius–Centaurus association.
NGC 6139 is a globular cluster of the Milky Way in the constellation Scorpius. It is located 3.6 kiloparsecs from the Galactic Center.
NGC 6153 is a planetary nebula in the constellation Scorpius. It was discovered in 1883 by Ralph Copeland.
Sh 2-1, also known as Sharpless 1, is the combination of a diffuse HII emission nebula and reflection nebula in the constellation of Scorpius with Pi Scorpii at its center. It appears as a modest brightness making it one of the easier Sharpless catalog objects for amateur astronomers to view. It features an apparent central star inside the nebulosity however it is not part its system nor a left over remnant.
Zeta2 Muscae, Latinized from ζ2 Muscae, is a star in the southern constellation of Musca. Its apparent magnitude is 5.16. This is a white main sequence star of spectral type A5V around 330 light-years distant from Earth. Like several other stars in the constellation, it is a member of the Lower Centaurus–Crux subgroup of the Scorpius–Centaurus association, a group of predominantly hot blue-white stars that share a common origin and proper motion across the galaxy. It is part of a triple star system with faint companions at 0.5 and 32.4 arc seconds distance. The former is an infrared source, the latter has a visual magnitude of 10.7.
The Ghost Nebula is a reflection nebula located in the constellation Cepheus.
Sh 2-297 is an emission nebula in the constellation Canis Major. The region was catalogued in 1959 in the extended seconded edition of the Sharpless catalogue. This area is part of the Canis Major OB1 Association, and is a very active area of new star formation.
Sh 2-308, also designated as Sharpless 308, RCW 11, or LBN 1052, and commonly known as the Dolphin-Head Nebula, is an H II region located near the center of the constellation Canis Major, composed of ionised hydrogen. It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like and surrounds a Wolf–Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution. The nebula is about 4,530 light-years away from Earth, but some sources indicate that both the star and the nebula are up to 5,870 ly (1,800 pc) away. Yet others indicate the nebula is as close as 1,875 ly (575 pc) from Earth.
References
- 1 2 3 "VizieR Detailed Page". Centre de Données astronomiques de Strasbourg. 20 December 2013.
- ↑ "CCD Images of the Sharpless Catalog". Dean Salman. 20 December 2013.
