Best Variable

Betelgeuse is a massive red supergiant star located within the constellation Orion. It’s notable due to its immense size and status as a pre-supernova object, making it a key subject for astronomers studying stellar evolution and potential catastrophic events. Scientists investigate Betelgeuse to un...

Algol is a binary star system notable for its predictable dimming due to an eclipsing orbit. The primary and secondary stars regularly pass in front of each other from our perspective, causing fluctuations in brightness. This behavior was one of the first astronomical phenomena to be explained throu...

Mira, designated Omicron Ceti, is a red giant star located approximately 420 light-years away in the constellation Cetus. It serves as the prototype for a class of long-period variable stars, known as Mira variables, which undergo dramatic changes in brightness due to physical pulsations. The star's...

T Tauri is a variable star found in the Taurus molecular cloud and serves as the prototype for the class of pre-main-sequence stellar objects known as T Tauri variables. Discovered in October 1852 by John Russell Hind, the star is part of a multiple-star system that includes several nascent celestia...

VY Canis Majoris is a red hypergiant star in the constellation Canis Major, located at an estimated distance of approximately 3,900 light-years from the Sun. Its radius has been estimated at roughly 1,400 times that of the Sun, making it one of the largest known stars, though the exact value remains...

Euphydryas editha (Edith's checkerspot) is a butterfly in the family Nymphalidae native to western North America, ranging from British Columbia to Baja California. It is a well-studied model organism in population and metapopulation biology, primarily through long-term field research initiated by Pa...

W Virginis is the prototype of the W Virginis variables, a class of pulsating variable stars also known as Type II Cepheids. These stars are Population II objects, meaning they are older and more metal-poor than classical Cepheid variables. W Virginis stars follow a period-luminosity relationship di...

UY Scuti is a red supergiant star in the constellation Scutum, classified as a semiregular variable with a pulsation period of approximately 740 days. Located near the center of the Milky Way at an estimated distance of about 5,100 light-years, the star has been identified as one of the largest know...

The Hubble’s Variable Nebula, formally designated NGC 2261, is a reflection nebula located in the Monoceros constellation. It's notable for its fluctuating brightness observed by Edwin Hubble in 1916, a key piece of evidence supporting his theories about extragalactic distances. Astronomers and rese...

Mu Cephei, historically known as Herschel's Garnet Star, is a massive red supergiant located in the constellation Cepheus. Visible to the naked eye, it is easily identified by its distinct deep red or garnet-colored hue. It is classified as a semiregular variable star, with its apparent magnitude fl...

Rho Cassiopeiae is a yellow hypergiant star situated in the northern constellation of Cassiopeia. It is recognized as one of the most massive and luminous stars in the Milky Way, with an estimated radius that places it among the largest known stars. The star exhibits complex, long-term variability a...

S Doradus is a Luminous Blue Variable (LBV) star located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. It serves as the prototype for its class of variable stars, which undergo dramatic changes in brightness and sporadic mass-loss events known as S Doradus outbursts. The star r...

The R Coronae Australis Nebula is a cloud of interstellar gas and dust in the constellation Corona Australis, associated with the young variable star R Coronae Australis. Its best known component, NGC 6729, is a variable reflection and emission nebula whose apparent brightness and shape can change a...

NGC 6729 is a variable emission and reflection nebula located within the Corona Australis molecular cloud complex. Discovered by astronomer Julius Schmidt in 1861, the cloud's illumination is driven by the variable young T Tauri star R Coronae Australis. As the brightness of R CrA fluctuates, the as...

Mirzam, officially designated Beta Canis Majoris, is a blue-white giant star located roughly 500 light-years from Earth in the constellation Canis Major. It serves as the prototype for the Beta Canis Majoris variables, a class of pulsating variable stars. The star is one of the brightest in the nigh...

The Variable Darner is a circumpolar dragonfly species native to North America, recognized for the highly variable and sometimes broken lateral thoracic stripes.

Sulcorebutia steinbachii is a small clustering cactus native to Bolivia, first collected by José Steinbach. It is recognized by its thick, hooked central spines and colorful flowers that may range from magenta to red. The species exhibits considerable variability across its natural habitat, with dif...

RW Cephei is an orange hypergiant star located in the constellation Cepheus. It is classified as an irregular variable star and ranks among the largest known stars in the Milky Way, with an estimated radius exceeding 1,500 times that of the Sun. The star's substantial size and mass place it near the...

Caph, officially designated as Beta Cassiopeiae, is a yellow-white giant star located approximately 54 light-years from Earth in the constellation Cassiopeia. It is one of the five vertices forming the distinctive 'W' asterism associated with the constellation, making it easily identifiable in the n...

V354 Cephei is a red supergiant star located in the Milky Way galaxy within the northern constellation of Cepheus. Astronomical observations indicate that the star possesses a radius estimated to be roughly 1,500 times greater than that of the Sun, placing it among the largest known stars in the uni...

Hind's Variable Nebula is NGC 1555 in Taurus, a reflection nebula lit by T Tauri and discovered by John Russell Hind in 1852.

KY Cygni is a heavily dust-enshrouded red supergiant star located in the Cygnus OB1 stellar association. It is classified as an M-type variable star and ranks among the largest known stars in the Milky Way. Astronomers estimate its radius to be around 1,400 times that of the Sun, though high levels...

The Two-spot Ladybird (Adalia bipunctata) is a carnivorous beetle belonging to the family Coccinellidae. It is a common species across the Northern Hemisphere, typically recognized by its red wing covers featuring one black spot on each. The species exhibits color variation, including a melanistic f...

Hubble's Variable Nebula, designated NGC 2261, is a fan-shaped reflection nebula located in the constellation Monoceros. It was first recognized for its changing appearance by astronomer Edwin Hubble in 1916, based on photographic plates taken over time. The nebula's variability is caused by shadows...

McNeil's Nebula is a variable reflection nebula in Orion, discovered by amateur astronomer Jay McNeil on January 23, 2004.

The Variable Checkerspot (Euphydryas chalcedona) is a butterfly species native to western North America, frequently found from the Pacific Northwest down through California and into Baja California. It is highly polymorphic, meaning its wing patterns vary significantly across different regions and s...

The ten-spot ladybird, Adalia decempunctata, is a ladybird beetle native to Europe and parts of Asia. It is highly polymorphic: individuals may be pale with dark spots, dark with pale markings, or intermediate in appearance, and the number of visible spots is not always ten. Adults and larvae feed m...

Originally named by naturalist Peter Simon Pallas in 1773, Celes variabilis is a Eurasian grasshopper noted for its highly variable coloration and cryptic behavior.

Gyulbudaghian's Nebula is a variable reflection nebula in Cepheus, discovered in 1977 and illuminated by the young star PV Cephei.