Canis Minor
“The Little Dog” · Both (straddles the celestial equator) · best around March evenings
Real star positions and magnitudes (HYG database via D3-Celestial, BSD-3). Lines are the conventional stick figure; north is up.
The story
Two stars and a name: Orion's smaller dog is really just brilliant Procyon — 'before the dog', rising minutes ahead of Sirius — with a companion white dwarf of its own. With Sirius and Betelgeuse it forms the Winter Triangle.
How to find it
The bright lone star east of Orion.
✦ What lives inside it
The deep dive
Researched for the Atlas from Wikipedia — Canis Minor (17,817 characters read) · updated Sep 20, 2026
01 A Two-Star Constellation With Ancient Roots
Canis Minor is one of the most stripped-down figures in the sky: Ptolemy, working in the second century, defined it with just two stars and admitted that no depiction of a dog was really possible with so little to work with. Yet the constellation's roots run far deeper than Greece. Procyon and Gomeisa appear in Mesopotamian star tablets dating to around 1100 BC, where they were called MASH.TAB.BA — meaning 'twins' — in the Three Stars Each tablets. Later Babylonian astronomy gave the group a second identity as DAR.LUGAL, positioned as 'the star which stands behind Orion', and the figure represented not a dog at all but a rooster. The Akkadian name for this asterism was tarlugallu. So a constellation we know today as the Lesser Dog spent its earliest recorded centuries as a pair of divine twins and a farmyard bird, before the Greek tradition recast it as the faithful hound trotting behind Orion the hunter.
02 Procyon: The Star That Gets There First
The name Procyon comes from the Greek for 'before the dog' or 'preceding the dog', because the star rises roughly an hour ahead of Sirius, the famous Dog Star in Canis Major. At magnitude 0.34 it is the eighth-brightest star in the entire night sky, and at 11.4 light-years (3.5 parsecs) from Earth it holds a notable record: the shortest distance to any northern-hemisphere first-magnitude star. Procyon is actually a binary system. The primary, Procyon A, is a yellow-white main-sequence star of spectral type F5 IV-V with 1.4 times the Sun's mass. Orbiting it every 41 years is Procyon B, a white dwarf of spectral type DA with 0.6 solar masses and a faint magnitude of 10.7 — far too dim to see without a telescope. Procyon A was originally classified in Roman-era texts under names like Antecanis and Praecanis, which are simply Latin translations of the Greek idea: the star that arrives before the dog.
03 Procyon's Surprising Neighbor: Luyten's Star Deeper
Only 12.39 light-years (3.80 parsecs) from Earth, Luyten's Star (catalogue number GJ 273) is the second-closest stellar neighbor to our Solar System within Canis Minor's borders. It is a red dwarf of spectral type M3.5V with a visual magnitude of 9.9, rendering it invisible to the naked eye despite its cosmic nearness. What makes Luyten's Star especially remarkable in relation to Procyon is their mutual proximity: the two stars are only 1.12 light-years apart from each other. At that separation, Procyon would blaze as the brightest star in Luyten's Star's own sky. The constellation also harbors YZ Canis Minoris, a red dwarf flare star of spectral type M4.5V and magnitude 11.2, located about 20 light-years (6.1 parsecs) away and roughly three times the size of Jupiter. YZ Canis Minoris emits unpredictable, brief outbursts of energy lasting mere minutes — potentially far more powerful analogues of solar flares.
04 Gomeisa: Fainter Here, Brilliant in Reality
At magnitude 2.89, Gomeisa — Beta Canis Minoris — is the second and final star in Canis Minor brighter than fourth magnitude, which tells you how sparse this constellation really is. Lying 160 ± 10 light-years (49.1 ± 3.1 parsecs) away, it is a blue-white main-sequence star of spectral class B8 Ve. Despite appearing much dimmer than Procyon to our eyes, Gomeisa is intrinsically far more powerful: it is 250 times as luminous and three times as massive as the Sun. Its Arabic name, ash-Shira al-Ghamisa, translates roughly as 'the Sirius with bleary eyes', a poetic allusion to its resemblance to Sirius while being notably fainter — the 'bleary' quality suggesting something slightly out of focus. Gomeisa is classified as a shell star and Gamma Cassiopeiae variable, meaning its brightness fluctuates slightly between magnitudes 2.84 and 2.92. It is surrounded by a disk of gas that the star heats until the disk emits its own radiation.
05 A Planet Around an Aging Giant Star Deeper
HD 66141 is one of the more intriguing stars in Canis Minor, even though it glimmers at only fourth magnitude (apparent magnitude 4.39). At 6.8 billion years old, it has long left the main sequence and bloated into an orange giant of spectral type K2III, with a diameter around 22 times that of the Sun, a mass of 1.1 solar masses, and a luminosity 174 times greater than the Sun's. It sits 222 ± 7 light-years from Earth. In 2012 astronomers detected a planet, HD 66141b, by measuring subtle shifts in the star's radial velocity. The planet carries a mass around 6 times that of Jupiter and completes one orbit every 480 days. The star has a mildly confused identity in the historical record: its celestial coordinates were recorded incorrectly when first catalogued, leading to the mistaken designation 13 Puppis, as if it belonged to the neighboring constellation Puppis. Johann Bode later assigned it the name Lambda Canis Minoris, a designation now considered obsolete.
06 Mythologies Beyond Greece: Dogs, Jackals, and Roosters
The Greeks themselves could not agree on which dog Canis Minor represented. Eratosthenes paired the Little Dog simply with Orion, while Hyginus linked it to Maera, the loyal dog of Icarius of Athens. According to Hyginus, when Maera discovered Icarius had been murdered, both the dog and Icarius's daughter Erigone took their own lives in grief; all three were placed in the sky, with Erigone becoming Virgo, Icarius becoming Boötes, and the faithful dog rewarded with a position along the banks of the Milky Way — which the ancients imagined as a heavenly river — so he would never thirst again. A separate myth connects Canis Minor with the Teumessian Fox, a monstrous beast chased by the magical hound Laelaps; Zeus turned both to stone and set them in the sky as Canis Major and Canis Minor respectively. Ancient Egyptians had a wholly different interpretation, identifying the constellation with Anubis, the jackal god — a fitting choice given Procyon's brilliance in the winter sky.
07 Arabic Astronomers and the Syrian Sirius Deeper
Medieval Arabic astronomers preserved the canine identity of Canis Minor, calling it al-Kalb al-Asghar. The tenth-century astronomer Abd al-Rahman al-Sufi included a diagram of the constellation in his Book of the Fixed Stars, with a canine figure overlaid on the star pattern. His treatment introduced one notable discrepancy from Ptolemy: al-Sufi claimed the star Mirzam — now assigned to Orion — as part of Canis Minor's collar as well. The Arabic names for the constellation's two bright stars both drew comparisons to Sirius. Procyon was known as ash-Shi'ra ash-Shamiya, the 'Syrian Sirius', referencing its prominence in the northern sky relative to the true Sirius. Gomeisa received the evocative name ash-Shira al-Ghamisa, 'the Sirius with bleary eyes'. Among the Merazig shepherds of Tunisia, the stars of Canis Minor were folded together with those of Canis Major into a seasonal marker called Merzem, signaling the onset of two weeks of hot, dry weather — a practical, calendar-oriented reading of the same stars that Greek mythologists turned into a loyal hound.
08 How Polynesia, China, and the Aztecs Read These Stars
Across the Pacific, Polynesian peoples generally did not recognize Canis Minor as a unified constellation, but they paid close attention to Procyon individually. In the Tuamotu Archipelago it was called Hiro, meaning 'twist as a thread of coconut fiber', and also Kopu-nui-o-Hiro, 'great paunch of Hiro'. In the Society Islands, Procyon carried the elaborate name Ana-tahua-vahine-o-toa-te-manava — 'the pillar for elocution'. In Chinese astronomy, Procyon, Gomeisa, and Eta Canis Minoris formed the asterism Nánhé, the Southern River, paired with the Northern River Beihe (formed by Castor and Pollux), together representing a gate or sentry post. A second Chinese asterism, Shuiwei, incorporated 6 and 11 Canis Minoris and represented an official who managed floodwaters. The Aztec calendar wove the stars of Canis Minor together with stars from Orion and Gemini into an asterism linked to the day called 'Water'. Australia's Wardaman people of the Northern Territory named Procyon and Gomeisa Magum and Gurumana — two humans transformed into gum trees in the Dreaming, who could still speak in a human voice by rustling their leaves.
09 Variable Stars: Pulsing, Flaring, Erupting Deeper
Despite its modest size, Canis Minor hosts a surprisingly varied collection of variable stars. At least three red giants are Mira variables: S Canis Minoris (spectral type M7e) is the brightest, swinging between magnitude 6.6 and 13.2 over a period of 332.94 days — a range of more than six magnitudes. V Canis Minoris oscillates between 7.4 and 15.1 over 366.1 days, while R Canis Minoris, an S-type star, varies from magnitude 7.3 to 11.6 over 337.8 days. BC Canis Minoris, a red giant of spectral type M4III about 500 light-years away, is a semiregular variable with recorded pulsation periods of 27.7, 143.3, and 208.3 days. The constellation also contains three Delta Scuti variables — AZ, AD, and BI Canis Minoris — which pulsate over periods of just 2.3, 2.95, and 2.91 hours respectively. These short-period pulsators are used both as standard candles and as subjects for astroseismology. Finally, DY Canis Minoris is a WZ Sagittae-type dwarf nova: in January and February 2008 it flared to magnitude 11.4, then dropped eight magnitudes to around 19.5 over approximately 80 days, as accumulated material on a white dwarf's accretion disk erupted dramatically.
10 The Lonely Deep-Sky Corner of the Lesser Dog
The Milky Way sweeps through much of Canis Minor, yet the constellation offers remarkably slim pickings for deep-sky observers. William Herschel catalogued four objects here in his 1786 Catalogue of Nebulae and Clusters of Stars, two of which he mistakenly identified as star clusters. NGC 2459 is actually just five thirteenth- and fourteenth-magnitude stars that happen to appear close together in projection but share no physical relationship. The same story applies to NGC 2394, a gathering of fifteen unrelated stars of ninth magnitude and fainter. More genuinely interesting is NGC 2508, a lenticular galaxy of thirteenth magnitude estimated at 205 million light-years away and spanning 80,000 light-years in diameter. Herschel also logged NGC 2402 as a single object, but it is in fact a pair of interacting galaxies — one elliptical, one spiral — of fourteenth and fifteenth magnitudes respectively, each roughly 55,000 light-years across and lying about 245 million light-years from Earth. All of these targets require a telescope, as none are visible to the naked eye.
11 The December Meteor Shower Nobody Knows
Each December, Earth passes through debris that produces the 11 Canis-Minorids, also called the Beta Canis Minorids. The shower runs from December 4 to 15, peaking on December 10 and 11. It was discovered in 1964 by Keith Hindley, who analyzed the meteors' trajectories and proposed they shared a common origin with comet D/1917 F1 Mellish. That hypothesis has since been challenged: subsequent researchers found that the number of orbits Hindley analyzed was too small and the trajectories too varied to confirm any real link with the comet. The radiant point of the shower lies near the fifth-magnitude star 11 Canis Minoris. The shower is not among the year's spectacular displays — its parent body connection remains unresolved, and it tends to be overshadowed by the far more active Geminid meteor shower, which peaks at nearly the same time in December.
12 Alternative Names and a Rogue Renaming Attempt
The constellation that eventually settled into the name Canis Minor has worn several other labels over the centuries, reflecting astronomers' varied priorities. Johann Bayer, working in the early seventeenth century, proposed calling it Fovea ('The Pit') or Morus ('Sycamine Tree'). His contemporary, the German poet and author Philippus Caesius, linked it instead to the dog of Tobias from the Apocrypha. The most ambitious renaming came in 1870, when Richard A. Proctor suggested calling it Felis — 'the Cat' — while simultaneously abbreviating Canis Major simply to Canis, reasoning that shorter names would make celestial charts more manageable. His cat never caught on. The constellation has also occasionally been confused with Canis Major and mislabeled Canis Orionis, meaning 'Orion's Dog'. Today the International Astronomical Union's three-letter abbreviation CMi, adopted in 1922, is the official shorthand, and the constellation boundaries were formally fixed by Belgian astronomer Eugène Delporte in 1930 as a 14-sided polygon covering 183 square degrees.