Reach for the Stars- STARS

Spica (α Virginis)

A B1III-IV star with an apparent magnitude varying between 0.92 and 1.04 over a 4-day period of time. Spica is a binary star system (companion Spica B is a B2V star) about 260 LY away. Its name comes from Latin for "Virgo's ear of grain".

Aldebaran (a Tauri "the Bull's Eye")

A K5III star (giant, not main sequence) with an apparent magnitude of 0.87, Aldebaran is the 13th brightest star in the nighttime sky. It is around 65 LY away, and it has a white dwarf companion Aldebaran B, with a classification of M2V. The name Aldebaran is from Arabic for "the follower" (because it follows the Pleiades across the night sky). The nickname "the Bull's eye" comes from its bright orange color and its position in the "Bull's head" asterism.

Algol (β Persei, the "Demon Star")

A triple star system, with Algol A as a B8V star, Algol B as a K0-2III star, and Algol C as a A5V star. Combined, it has an apparent magnitude of 2.1, which drops to 3.4 every 3 days or so when Algol A is eclipsed by Algol B (called an eclipsing binary). "Algol" is from Arabic for "head of the ghoul".

Antares (a Scorpii)

Antares is a M1.51 star (a supergiant), with an apparent magnitude ranging from 0.9 to 1.8 (it's a variable star). The ancient Greek for "against Mars" (roughly, anti-Ares) became the modern day name of Antares. About 600 LY away, it is also the 16th brightest star in the sky, even though a large portion of its emitted energy is in the infrared wavelengths. Its companion Antares B is a B2.5V star.

Regulus (α Leonis)

Around 77.5 LY away, Regulus is a quadruple star system- Regulus A is a B7V star with a white dwarf companion, while Regulus B and C are dim main sequence stars (a K1-2V star and a M5V star, respectively). Regulus A is a young star that spins very rapidly and it has a magnitude of 1.35. The name comes from Latin for "little king" or "prince".

Proxima Centauri

At only 4 light years, Proxima centauri is the nearest star to the sun. It is a type-M red dwarf star, and despite its distance, it is too dim to see with the naked eye, at magnitude 11.05. Proxima Centauri is part of a triple star system with its brighter neighbor Alpha Centauri A and B. It is a flare star, a variable type that changes brightness drastically.

Betelgeuse (α Orionis)

Betelgeuse (yes, pronounced beetle-juice) is a M2I red supergiant about 600 LY away. It is most likely a young star evolving quite rapidly. Betelgeuse is usually the second brightest star in Orion with an apparent magnitude of around 0.58, but since it's a variable star, Betelgeuse is sometimes brighter than Rigel. Also, it is one of the vertices of the Winter Triangle, along with Sirius and Procyon. "Betelgeuse" comes from a mistranslation of the Arabic phrase for "hand of the central one". Betelgeuse is considered very likely to go supernova after its red giant phase.

Castor & Pollux (α and β Geminorum, respectively)

Castor is the second brightest star in the constellation Gemini, named after one of the twin sons of the Greek god Zeus. Castor is actually a sextuple star system, with two pairs of A-class stars (1V and 2V) and M-class stars orbited by two more M-class dwarfs. The apparent magnitude can be either 1.96 or 2.91, depending on which of the A-class stars is measured. Pollux is the brightest star in Gemini, with an apparent magnitude of 1.14. It's 34 light-years from Earth and it's also a K0 III star, meaning that it is one of the hotter orange giants. Pollux is also one of the only giant stars with a planet. This planet has a mass at least 2.9 times that of Jupiter and orbits 1.69 AUs from its host star.

γ Velorum

Far in the southern sky lies a very interesting star - Gamma Velorum. It is an extremely luminous Wolf-Rayet star, which is a type of massive star that is losing mass due to a stellar wind at a violent rate. Currently, Gamma Velorum is about 10 times the mass of the sun, it was initially over 20 times heavier than the sun, but has been losing mass rapidly. It orbits another highly-luminous blue supergiant. From Earth, it appears at apparent magnitude 1.27.

Gliese 581

Gliese 581 is a red dwarf, M3V star about 20 LY away. The star has an apparent magnitude between 10.56 and 10.58 and is located in the constellation Libra. The star is well known for its planet Gliese 581 g, thought to be in the habitable zone of its star, but the planet's existence is disputed

Rigel (β Orionis)

Named in Arabic "left foot of the central one", Rigel is an important star for navigation. Somewhere between 700 and 900 LY away, Rigel is also known as the most luminous star in the nearby Milky Way. Most of the time, it is the brightest star in Orion, but Betelgeuse can be brighter because it is a variable star. Rigel is known to be a triple star system; however, it may in fact be a quadruple star system. The most prominent star is a B8I star with an apparent magnitude of 0.11.

Deneb (α Cygni)

One of the vertices of the Summer Triangle, Deneb is an A2I star about 1550 LY away. With an apparent magnitude of 1.25, Deneb is actually the farthest 1st-magnitude star from Earth. It will probably become a supernova in a few million years. Because Deneb is the tail of Cygnus, the swan, its Arabic name is quite fittingly, "tail".

Capella (α Aurigae)

Part of the Hyades moving group, Capella is the 6th brightest star in the night sky and the 3rd brightest in the northern celestial hemisphere. It is actually a "star system" of 4 stars in 2 pairs. The first pair are G8III and K0III stars (probably previously A-class stars that have now moved off the main sequence and are becoming red giants) while the second pair consists of 2 small, cool, dim red dwarfs. Combined, these stars have an apparent magnitude of 0.08; additionally, they are 42.2 LY from Earth. There are lots of x-rays being emitted from the corona of the largest star. Capella means "she-goat."

Polaris (α Ursae Minoris, "North Star", the "Pole Star")

Polaris is an important star for navigation; however, it is only approximate North - it's not exactly at the celestial pole. Polaris A is a F7I-II star, while companions Polaris B and Ab are a F-class main sequence star and a dwarf, respectively (there are also 2 farther stars, Polaris C and D). Polaris may be part of a loose cluster of A- and F-class stars.

Procyon (α Canis Minoris)

Procyon is the 7th brightest star in the nighttime sky with an apparent magnitude of 0.34. Procyon is a binary star system (Procyon A is a F5IV-V star, Procyon B is a white dwarf) and it's also a vertex of the Winter Triangle. Procyon forms a prominent equilateral triangle with Sirius and Betelgeuse. In Greek, Procyon means "preceding the dog", because it rises before Sirius.

Sirius (α Canis Majoris, the "Dog Star")

Sirius is the brightest star in the night sky, with an apparent magnitude of -1.47. The binary star system consists of Sirius A (an A1V star) and Sirius B (which used to be even larger than Sirius A but has evolved into a white dwarf). Sirius can be seen up to 73 degrees north or south of the equator, and it's one of the vertices of the Winter Triangle, along with Procyon and Betelgeuse. The nickname "Dog Star" comes from the constellation Sirius is in: Canis Major, the Big Dog. Sirius is about 8.6 LY away.

Altair (a Aquilae)

The 12th brightest star in the sky with an apparent magnitude of 0.77, Altair is one of the vertices of the Summer Triangle (along with Vega and Deneb). It is flattened at the poles due to its high rotation speed. The name Altair comes from a shortened version of the Arabic phrase "the flying eagle". Altair is a A7V star and it's 16.8 LY away.

Mizar & Alcor

The sextuple system Mizar and Alcor is located on the handle of the Big Dipper Asterism in Ursa Major. Mizar is actually made up of two binary systems, while Alcor is a binary system itself. The stars have an apparent magnitude of 2.23. It looks like a single star at a glance, but a person with keen eyesight can see both Mizar and Alcor. For this reason, it has been important to navigators and explorers throughout history. However, Mizar is not actually in a system with Alcor; they are separate star systems that appear very close from Earth.

HL Tau

This very young star is dim and located 520 light years away in the constellation of Taurus. The star has a very large and bright "accretion disk", which is a disk of gas and dust surrounding the star. Because of this, it was a good candidate to witness a planet in forming, called a "protoplanet". After a few studies, it was revealed that there was a ball of Gas and Dust 14-times the mass of Jupiter -- A planet forming. It is the youngest planet ever discovered.

Vega (α Lyrae)

Vega is the 5th brightest star in the night sky and the 2nd brightest in the northern celestial hemisphere. It is an A0V star approximately 25 LY away that is flattened at the poles due to its high rotation speed. Vega is 1/10 the age of the Sun, but it's already halfway through its life as a main sequence star. There is the possibility that Vega has its own little solar system of sorts- it may have orbiting planets. Vega is a vertex of the Summer Triangle (the other vertices are Altair and Deneb). The name is derived from the Arabic phrases for either "falling eagle" or "swooping vulture".

Arcturus (α Bootïs)

With an apparent magnitude of -0.05 (can vary by 0.04), Arcturus is the fourth brightest star in the nighttime sky. However, it is less bright than Alpha Centauri A and B combined, which means that it is the third brightest individual star in the night sky. Arcturus might actually be a binary star with a companion around 20 times or so dimmer, at the very edge of our ability to detect it. Arcturus is about 36.7 LY away and is a K1.5III star. The name is derived from Arabic for "bear guard", because it is close to both Ursa Major and Ursa Minor