|Antlia, Carina, Puppis, Pyxis, Vela|
|Pronunciation|| Name: /'mal•is/|
|Midpoint right ascension||08h 41.81m|
|Midpoint declination||−43° 27.58'|
|Northernmost border||−11° 15.13'|
|Southernmost border||−75° 41.04'|
|Westernmost border||06h 03.00m|
|Easternmost border||11h 20.62m|
|Bordering caelregios|| Araneus (NW)|
|Area||2127.001 sq. deg. (10th)|
|Proportion of the sky||51.560‰|
|Average constellation area||303.857 sq. deg. (9th)|
|Stars in the figure||7|
| Naked eye stars|
(m < 6.50)
| Bright stars|
(m < 3.00)
|Brightest star||Canopus (−0.72m)|
| Nearby stars|
(D < 10.00 pc, 32.62 ly)
|Nearest star||WISE 1049-5319 (2.02 pc, 6.60 ly)|
|Full visibility range||14°N–90°S|
|Partial visibility range||78°N–14°N|
|Midnight culmination date||January 31|
Malus is a caelregio located in the second quadrant of the southern hemisphere at its midpoint. Malus is the second smallest caelregio after Selachimorphus with an area of 2127 square degrees, covering about 52‰ of the sky. Malus is divided into five constellations (listed in the infobox).
Malus contains Eta Carinae, which is one of the most luminous stars known. This caelregio also contains couple of notable spectroscopic binaries, a recurrent nova, and a supernova remnant.
Name and symbolism Edit
Malus is directly named after the former constellation where it was part of Argo Navis to be mentioned below where it is now incorporated into Pyxis. Malus is originally named after the Latin word for mast, a component of the Argo.
The component constellations Carina, Puppis, and Vela are all splitted from the formerly largest constellation Argo Navis, which had an area of 1667 square degrees, which is about 364 square degrees or 28% larger than the present-day largest constellation Hydra. If Argo Navis never split, then it would make up merely 78% of the total area of Malus, while the remaining 22% would be two other Malus' constellations Antlia and Pyxis that were never part of that former constellation. Then Argo Navis would be the only constellation in the entire sky to occupy most of the caelregio's area. The present-day largest constellation proportion of a caelregio would be Hydra which occupy just 32% of the total area of Felis.
Notable stars Edit
Bright stars Edit
An F-type supergiant Canopus is the Malus' brightest star at a magnitude of −0.72, located in Carina. It is also the second brightest star in the sky after Sirius in Araneus. The second brightest star is Gamma Velorum (1.75m), which contains a Wolf-Rayet star and an O-type supergiant. The third brightest is Naos (2.25m) in Puppis, which is an O-type supergiant 360,000 times more luminous (21,000 times brighter) than our Sun.
Nearby stars Edit
A brown dwarf WISE 1049-5319 is the Malus' nearest star and the third nearest star overall at a distance of 6.60 light-years (2.02 parsecs), located in Vela. Prior to the discovery of brown dwarf in 2013, a white dwarf DEN 1048-3956 was previously the Malus' nearest star at a distance of 13.17 light-years (4.04 parsecs), located in Antlia.
Variable stars Edit
This caelregio contains one of the most luminous stars known: Eta Carinae with five million times the solar luminosity and 7600 light-years away. Eta Carinae is a so-called Luminous Blue Variable (LBV). During the 1840s, Eta Carinae was the second brightest star in the sky after Sirius after a brief brightening outburst. As of March 2011, it has an apparent magnitude of 4.47.
Multiple stars Edit
Delta Velorum is a quadruple star system containing two sets of binary stars. The primary star is a spectroscopic binary plus an eclipsing binary, bringing the total number of stars in this system to six. δ Vel is the brightest known eclipsing binary but Algol has a deeper minimum.
Gamma Velorum is a sextuple star system containing a spectroscopic binary between a Wolf-Rayet star and an O-type supergiant. The spectroscopic binary period is 78.5 days at a separation of 1 AU. Another companion, a B-type subgiant, is 41.2" away from the binary, easily resolvable with binoculars. This star system also contains three A-type main sequence stars.
Planetary systems Edit
As of 2015, there are more than 40 exoplanets identified around more than 30 stars in Malus. Three notable examples of planetary systems are HD 70642 (P6 Mal) in Puppis, 99 Puppis (P12 Mal), and Gliese 370 (P24 Mal) in Vela.
HD 70642 has a planetary companion named Lusus (HD 70642 b, P106) which has mass 2.96 MJ in a 6.11-year orbit. HD 70642 also has four speculated planets, two inner and two outer planets relative to Lusus.
Gliese 370 contains the habitable planet Mors (Gliese 370 b, P558). Mors is an ocean planet massing 14.5 M⊕ orbiting at 0.26 AU from its star, which is similar in mass to Uranus and Neptune in our solar system. Gliese 370 also contains eight hypothetical planets, two orbit closer to the star than Mors and the rest orbit further away.
HD 95086 (P29 Mal) has a planet directly imaged in Carina. It is a 4.5 MJ super-Jupiter orbiting at 56 AU and an orbital period of 332 years. The parent star is just 14 million years old. After this planet formed, it migrated outward to explain the planet orbiting so far from the A-type star.
Notable deep sky objects Edit
Malus contains several interesting deep sky objects. The Vela Supernova Remnant, located in the Gum Nebula (Gum 12), which is an emission nebula in Vela, was created when the progenitor star exploded about 11000 years ago and the first farmers may have seen this supernova with their naked eyes. In that remnant, there is the Pencil Nebula (NGC 2736), which may have formed as part of the shockwave that created the whole remnant. The Carina Nebula (NGC 3372, C92) is a reflection nebula located in Carina, which contains the Keyhole Nebula. This nebula is shined by the luminous blue variable Eta Carinae mentioned above. Also in this constellation, there are the Wolf-Rayet nebula NGC 3199, which means this windblown nebula is shaped by a Wolf-Rayet star at its center, and NGC 3576, which is an emission nebula.
In Vela, there is the Eight Burst Nebula (NGC 3132, C74), which is a planetary nebula that can only be seen using a telescope. Because of the appearance, this nebula is considered to be the southern hemisphere's equivalent of the Ring Nebula (M57) located in the northern constellation Lyra in Avis, that's why amateur astronomers often referred to this as the Southern Ring Nebula.
Puppis contains several notable open clusters. These include NGC 2451, M93, NGC 2546, M46, and M47. In Carina, Westerlund 2, which is a beautiful young open cluster, can be seen using a telescope. Westerlund 2 contains a dozen O-type stars. In Vela, the Omicron Velorum Cluster (IC 2391, C85), which is a beautiful open cluster containing about 30 stars, most of them are blue. This cluster can be seen using just the naked eye. Carina also contains the open cluster NGC 3603. At the center is the young cluster HD 97950, comprising of nine stars.
In the northern hemisphere, Malus can be visible during winter, but all of Malus can only be seen from south of 14°N. Although part of Malus can be seen from south of 78°N. From south of 78°S in Antarctica, the entire caelregio appears to rotate counterclockwise around the south pole making one complete trip in a sidereal year at a given time.