|Cancer, Crater, Hydra, Leo Major, Leo Minor, Lynx, Sextans|
|Midpoint right ascension||10h 39.38m|
|Midpoint declination||+14° 08.11'|
|Northernmost border||+61° 57.85'|
|Southernmost border||−35° 41.63'|
|Westernmost border||06h 16.23m|
|Easternmost border||15h 02.52m|
|Bordering caelregios||Araneus (W)|
Malus (S (W))
Simianus (S (E))
|Area||4128.935 sq. deg. (6th)|
|Proportion of the sky||100.088‰|
|Average constellation area||589.848 sq. deg. (4th)|
|Stars in the figure||21|
|Naked eye stars
(m < 6.50)
(m < 3.00)
|Brightest star||Regulus (1.35m)|
(D < 10.00 pc, 32.62 ly)
|Nearest star||Wolf 359 (2.39 pc, 7.78 ly)|
|Full visibility range||54°N–28°S|
|Partial visibility range||90°N–54°N|
|Midnight culmination date||February 28|
Felis is a caelregio located in the second quadrant of the northern hemisphere at its midpoint, but it extends into the southern hemisphere and into the third quadrant. Felis is divided into seven constellations (listed in the infobox), including the largest constellation Hydra.
This caelregio contains several notable bright stars, a couple of notable planetary systems, and many examples of galaxies and dwarf galaxies.
Name and symbolism
Felis is named after the Latin word for cat, because Felis contains couple of constellations named after cat species, including Leo Major the great lion, Leo Minor the little lion, and Lynx the lynx. On the celestial map, Felis shapes like a cat sitting on its butt with narrow eastern half of Hydra shaping like a tail.
A B-type main sequence Regulus is the Felis' brightest star at a magnitude of 1.35, located in Leo Major. Regulus is one of the four brightest stars within 5° of the ecliptic, the others are Spica in Noctua, Antares in Simianus, and Aldebaran in Araneus.
A flaring red dwarf Wolf 359 (also designated CN Leonis because it is a UV Ceti variable star) is the Felis' nearest star at a distance of 7.78 light-years (2.39 parsecs). It is also the fourth nearest star system overall after the Alpha Centauri system in Simianus and Barnard's Star in Tarandus. However with a magnitude of 13.54, Wolf 359 can only be visible with a large telescope. It is one of the least massive stars known massing just 9% of the Sun's mass.
As 2015, there are about 80 exoplanets orbiting around more than 60 stars in Felis. One of the most notable examples is 55 Cancri (P1 Fel), which has five planets (four of them are gaseous) and speculatively contains two undetected planets as well.
Another notable example is Gliese 436 (P8 Fel) in Leo Major, which contains the transiting midplanet Nemea (Gliese 436 b, P120) as well as two sub-Earths candidate and three hypothetical planets within 0.3 AU from the star. Nemea has an exotic form of water called "hot ice." Nemea's distance from the feeble parent star is 1⁄36 the Earth-Sun distance and has mass 22 times that of Earth and radius 41⁄4 times that of Earth, yielding a mean density nearly 50% greater than water and over one quarter the Earth's.
Three stars in M67 were found to have planets.
Notable deep sky objects
Felis contains several interesting deep sky objects. The Beehive Cluster (sometimes known as Praesepe) (M44, NGC 2632), which is an open cluster located in Cancer, M83 (sometimes called the Southern Pinwheel Galaxy, the Southern Whirlpool Galaxy or the Thousand Ruby Galaxy) (NGC 5236), which is a barred spiral galaxy located in Hydra, and a pair of dwarf galaxies in Leo Major: Leo I (PGC 29488) and Leo II (PGC 34176).
In Leo Major, it contains the Silverado Galaxy (NGC 3370), which is a spiral galaxy similar in size and mass to the Milky Way. Also in that same constellation, there is the peculiar spiral galaxy M65. M65 is one of three galaxies that form the Leo Triplet, the other two are M66 and NGC 3628. Another spiral galaxy in Leo Major is NGC 3521 with long spiral arms dotted with star-forming regions and a bright, compact nucleus.
There are two barred spiral galaxies in Leo Major: NGC 2903 and M95 (NGC 3351). M95 is a member of the Leo I galaxy group that also includes M96 (NGC 3368), M105 (NGC 3379), and several fainter NGC galaxies. M105 is an elliptical galaxy.
In Hydra, there is the Ghost of Jupiter (NGC 3242, C59), which is a planetary nebula that resembles the appearance of an human eye. Because of this appearance, this nebula can also be called the Eye Nebula. Also in this constellation, we find the open cluster M48. Located in Lynx, there is the globular cluster NGC 2419 (also known as the Intergalactic Tramp) (C25).
Notable meteor showers
The Leonids (also called Felids) tend to peak in mid-November every year radiating from Leo Major. This meteor shower is associated with the comet Tempel-Tuttle. It can sometimes be seen as a meteor storm approximately every 33 years when more than 1000 meteors per hour would be visible. The last meteor storm occurred in 2001.
In the northern hemisphere, Felis can most prominently be visible during winter. All of Felis can be visible from around the world except for the north polar region, south temperate zone, and south polar zone.
The most recognizable constellation in Felis is Leo Major which contains five bright stars, but other constellations except Hydra are faint and containing no bright stars (m<3.00).
The Sun appears to cross Felis from July 21 till September 15: it crosses the constellations Cancer (July 21 till August 9) and then Leo Major (August 10 till September 15). This zodiacal caelregio is located between Araneus to the west and Noctua to the east.
Felis was formerly in the sign of zodiac from June 22 till August 21.