Bayer designation and Related Topics

Orion (constellation)

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Prominent constellation located on the celestial equator and visible throughout the world.

Orion, photographed from Kuantan, Malaysia

Star formation in the constellation Orion as photographed in infrared by NASA's Spitzer Space Telescope

The constellation of Orion, as it can be seen by the naked eye. Lines have been drawn.

Using Orion to find stars in neighbor constellations

Orion as depicted in Urania's Mirror, a set of constellation cards published in London c.1825

This view brings out many fainter features, such as Barnard's Loop.

Animation showing Orion's proper motion from 50000 BC to 50000 AD. Pi3 Orionis moves the most rapidly.

Betelgeuse, also designated Alpha Orionis, is a massive M-type red supergiant star nearing the end of its life. It is the second brightest star in Orion, and is a semiregular variable star. It serves as the "right shoulder" of the hunter it represents (assuming that he is facing the observer). It is generally the eleventh brightest star in the night sky, but this has varied between being the tenth brightest to the 23rd brightest by the end of 2019. The end of its life is expected to result in a supernova explosion that will be highly visible from Earth, possibly outshining the Earth's moon and being visible during the day. This is most likely to occur within the next 100,000 years.

A visual band light curve for YY Geminorum (Castor C), adapted from Butler et al. (2015)

Castor (star)

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Second-brightest object in the zodiac constellation of Gemini.

It has the Bayer designation α Geminorum, which is Latinised to Alpha Geminorum and abbreviated Alpha Gem or α Gem.

Betelgeuse

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Usually the tenth-brightest star in the night sky and, after Rigel, the second-brightest in the constellation of Orion.

1998/9 UV HST images of Betelgeuse showing asymmetrical pulsations with corresponding spectral line profiles

AAVSO V-band magnitude of Betelgeuse, between September 2018 and February 2021

Comparison of SPHERE images of Betelgeuse taken in January 2019 and December 2019, showing the changes in brightness and shape

Image showing Betelgeuse (top left) and the dense nebulae of the Orion molecular cloud complex ( Rogelio Bernal Andreo )

NRAO's Very Large Array used to derive Betelgeuse's 2008 distance estimate

AAVSO V-band light curve of Betelgeuse (Alpha Orionis) from Dec 1988 to Aug 2002.

Orion, with Betelgeuse at its usual magnitude (left) and during the unusually deep minimum in early 2020 (right)

Radio image from 1998 showing the size of Betelgeuse's photosphere (circle) and the effect of convective forces on the star's atmosphere

Infrared image of Betelgeuse, Meissa and Bellatrix with surrounding nebulae

Size comparison of Betelgeuse, Mu Cephei, KY Cygni, and V354 Cephei, according to Emily Levesque

Image from ESO's Very Large Telescope showing the stellar disk and an extended atmosphere with a previously unknown plume of surrounding gas

Artist's rendering from ESO showing Betelgeuse with a gigantic bubble boiling on its surface and a radiant plume of gas being ejected to six photospheric radii or roughly the orbit of Neptune

Exterior view of ESO's Very Large Telescope (VLT) in Paranal, Chile

Interior view of one of the four 8.2-meter Unit Telescopes at ESO's VLT

This infrared image from the ESO's VLT shows complex shells of gas and dust around Betelgeuse – the [[:File:Nebula and betelgeuse VLT.jpg|tiny red circle]] in the middle is the size of the photosphere.

Hertzsprung–Russell diagram identifying supergiants like Betelgeuse that have moved off the main sequence

Celestia depiction of Orion as it might appear from Earth when Betelgeuse explodes as a supernova, which could be brighter than the supernova that exploded in 1006

An illustration of Orion (horizontally reversed) in al-Sufi's Book of Fixed Stars. Betelgeuze is annotated as Yad al-Jauzā ("Hand of Orion"), one of the proposed etymological origins of its modern name, and also as Mankib al Jauzā' ("Shoulder of Orion").

Dunhuang Star Chart, circa AD 700, showing 参宿四 Shēnxiùsì (Betelgeuse), the Fourth Star of the constellation of Three Stars

Its Bayer designation is α Orionis, Latinised to Alpha Orionis and abbreviated Alpha Ori or α Ori.

Star

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Astronomical object comprising a luminous spheroid of plasma held together by its gravity.

Infrared image from NASA's Spitzer Space Telescope showing hundreds of thousands of stars in the Milky Way galaxy

Stellar evolution of low-mass (left cycle) and high-mass (right cycle) stars, with examples in italics

An example of a Hertzsprung–Russell diagram for a set of stars that includes the Sun (center) (see Classification)

Betelgeuse as seen by ALMA. This is the first time that ALMA has observed the surface of a star and resulted in the highest-resolution image of Betelgeuse available.

Onion-like layers at the core of a massive, evolved star just before core collapses

The Crab Nebula, remnants of a supernova that was first observed around 1050 AD

Artist's impression of the Sirius system, a white dwarf star in orbit around an A-type main-sequence star

This view of NGC 6397 includes stars known as blue stragglers for their location on the Hertzsprung–Russell diagram.

Some of the well-known stars with their apparent colors and relative sizes

The Pleiades, an open cluster of stars in the constellation of Taurus. These stars share a common motion through space.

Surface magnetic field of SU Aur (a young star of T Tauri type), reconstructed by means of Zeeman–Doppler imaging

The reflection nebula NGC 1999 is brilliantly illuminated by V380 Orionis. The black patch of sky is a vast hole of empty space and not a dark nebula as previously thought.

The asymmetrical appearance of Mira, an oscillating variable star

Internal structures of main sequence stars with masses indicated in solar masses, convection zones with arrowed cycles, and radiative zones with red flashes. Left to right, a red dwarf, a yellow dwarf, and a blue-white main sequence star

Overview of consecutive fusion processes in massive stars

The German astronomer Johann Bayer created a series of star maps and applied Greek letters as designations to the stars in each constellation.

Gemini (constellation)

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One of the constellations of the zodiac and is located in the northern celestial hemisphere.

The constellation Gemini as it can be seen with the unaided eye, with added connecting lines.

An animation of the constellation Gemini (center), "the twins", shows two parallel stick figures. Gemini is associated with the myth of Castor and Polydeuces (also known as Pollux), collectively known as the Dioscuri.

Gemini as depicted in Urania's Mirror, a set of constellation cards published in London c.1825.

Sculpture showing Castor and Pollux, the legend behind the third astrological sign in the Zodiac and the constellation of Gemini

Diagram of H. A. Rey's alternative way to connect the stars of the constellation Gemini. Twins are shown holding hands.

Castor's Bayer designation as "Alpha" arose because Johann Bayer did not carefully distinguish which of the two was the brighter when he assigned his eponymous designations in 1603.