Constellation: Ophiuchus

Ophiuchus constellation lies in the southern sky, near the celestial equator. Its name means “the serpent bearer” in Greek.

It is pronounced /ˌɒfiːˈjuːkəs/ (off-ee-YOO-cuss). The constellation is associated with the figure of Asclepius, the famous healer in Greek mythology. It was one of the constellations first catalogued by the Greek astronomer Ptolemy in the 2nd century. Sometimes, it is also known by its Latin name, Serpentarius.

Ophiuchus is generally depicted as a man holding a snake, represented by the neighboring constellation Serpens, which is divided into two parts by Ophiuchus: Serpens Caput, the snake’s head, and Serpens Cauda, the snake’s tail. The snake is usually depicted coiled around his waist.

Even though Ophiuchus is one of the constellations that cross the ecliptic and there have been attempts to include it among the signs of the zodiac, it does not belong to the Zodiac family, but to the Hercules family of constellations.

Stars at Ophiuchus

1. Rasalhague – α Ophiuchi (Alpha Ophiuchi)

Rasalhague (or Ras Alhague) is the brightest star in Ophiuchus. It has an apparent magnitude of 2.07 and is approximately 48.6 light years distant from Earth. It is a binary star with an orbital period of 8.62 years.

The primary component in the system is a white giant star with the stellar classification of A5 III. It has a mass 2.4 times that of the Sun. The companion is an orange main sequence dwarf with 85 percent of the Sun’s mass. It belongs to the stellar class K5-7 V.

The brighter component is about 25 times more luminous than the Sun. It is a very fast spinner, with a projected rotational velocity of 240 km/s. As a result, it has an equatorial bulge that is about 20 percent larger than the polar radius, which gives Alpha Ophiuchi the shape of an oblate spheroid.

The star’s traditional name, Rasalhague, is derived from the Arabic raʾs al-ḥawwἄ, which means “the head of the serpent collector.” The star marks Asclepius’ head.

2. Sabik – η Ophiuchi (Eta Ophiuchi)

Eta Ophiuchi is the second brightest star in the constellation. It has a combined visual magnitude of 2.43 and is approximately 88 light years distant from the Sun. It is a binary star that is not easy to resolve in smaller telescopes. The system is composed of two white main sequence dwarfs belonging to the spectral classes A1 V and A3 V. They have an orbital period of 87.58 years. The stars have apparent magnitudes of 3.05 and 3.27.

3. Zeta Ophiuchi – ζ Ophiuchi (Zeta Ophiuchi) Like a ship plowing through cosmic seas, runaway star Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the left at 24 kilometers per second. Its strong stellar wind precedes it, compressing and heating the dusty interstellar material and shaping the curved shock front. Around it are clouds of relatively undisturbed material. What set this star in motion? Zeta Oph was likely once a member of a binary star system, its companion star was more massive and hence shorter lived. When the companion exploded as a supernova catastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Oph is 65,000 times more luminous than the Sun and would be one of the brighter stars in the sky if it weren’t surrounded by obscuring dust. The image spans about 1.5 degrees or 12 light-years at the estimated distance of Zeta Ophiuchi. Image: NASA, JPL-Caltech, Spitzer Space Telescope

Zeta Ophiuchi is the third brightest star in Ophiuchus. It is an extremely large blue main sequence star with the stellar classification of O9.5 V.

It has an apparent magnitude of 2.569 and is about 366 light years distant from the solar system. The star is classified as a Beta Cephei variable, a star that exhibits variations in brightness as a result of pulsation of its surface.

Within the next few million years, the star will expand into a red supergiant and likely explode as a supernova, leaving behind a pulsar or neutron star.

Zeta Ophiuchi has 8 times the Sun’s radius and more than 19 solar masses.

It is a fast rotating star, spinning close to the velocity at which it could begin to break up. Its estimated rotational velocity may be 400 km/s. The star’s estimated age is only 3 million years.

4. Yed Prior – δ Ophiuchi (Delta Ophiuchi)

Delta Ophiuchi is a red giant with the stellar classification of M0.5 III. It is the fourth brightest star in the constellation. It has an apparent magnitude of 2.75 and is approximately 171 light years distant from the Sun.

It forms an optical double with the star Epsilon Ophiuchi, or Yed Posterior. The word “yed” comes from Arabic and means “the hand.” The two stars mark the left hand of the Serpent Bearer, which holds the head of the serpent.

Delta Ophiuchi has a mass 1.5 times that of the Sun and a radius about 59 times solar. It is a suspected variable star with possible variations in magnitude by 0.03.

5. Celbalrai – β Ophiuchi (Beta Ophiuchi)

Beta Ophiuchi is an orange giant star belonging to the spectral class K2 III. It is the fifth brightest star in the constellation. It has a visual magnitude that ranges from 2.75 to 2.77 and is 81.8 light years distant from Earth. The star’s traditional name, Celbalrai (and variants Cheleb and Kelb Alrai) comes from the Arabic kalb al-rā‘ī, which means “the shepherd dog.”

Celbalrai has 113 percent of the Sun’s mass and a radius 12.42 times solar. The star is 63.4 times more luminous than the Sun. It has an unconfirmed planetary companion in its orbit.

6. κ Ophiuchi (Kappa Ophiuchi)

Kappa Ophiuchi is another suspected variable star in Ophiuchus. It is an orange giant with the stellar classification of K2 III. It has a mean apparent magnitude of 3.20 and is 91.5 light years distant from the Sun.

Kappa Ophiuchi has 119 percent of the Sun’s mass and 11 times the solar radius. It is 46 times more luminous than the Sun.

7. Yed Posterior – ε Ophiuchi (Epsilon Ophiuchi)

Epsilon Ophiuchi is a yellow giant star belonging to the spectral class G9.5 IIIb. It has a visual magnitude of 3.220 and is 106.4 light years distant from the solar system. It is 1.85 times more massive than the Sun and has a radius 10.39 times solar. The star is 54 times more luminous than the Sun. Its estimated age is about a billion years.

8. θ Ophiuchi (Theta Ophiuchi)

Theta Ophiuchi is a multiple star system that marks Ophiuchus’ right foot. It has an apparent magnitude of 3.26 and is approximately 436 light years distant from the solar system.

The primary component in the system is a spectroscopic binary with the stellar classification of B2 IV, matching the spectrum of a blue-white subgiant star. It is 5,000 times more luminous than the Sun. The star is classified as a Beta Cephei variable.

9. Sinistra – ν Ophiuchi (Nu Ophiuchi)

Nu Ophiuchi is an orange giant with the stellar classification of K0 IIIa CN-1. It has an apparent magnitude of 3.332 and is approximately 151 light years distant from the Sun. The star is three times more massive than the Sun, has 14 times the solar radius, and is 123 times more luminous than the Sun.

A brown dwarf was discovered orbiting the star in early 2004. The dwarf has a mass at least 21.9 times that of Jupiter and orbits the star with a period of 536 days. In 2010, another brown dwarf companion was discovered, one with at least 24.5 Jupiter masses and an orbital period of 3,169 days.

The star’s traditional name, Sinistra, means “the left side” in Latin.

10. γ Ophiuchi – Gamma Ophiuchi

Gamma Ophiuchi is a white main sequence dwarf with the stellar classification of A0 V. It has a visual magnitude of 3.75 and is approximately 95 light years distant from Earth. The star’s estimated age is about 184 million years.

Gamma Ophiuchi has a mass 2.9 times that of the Sun, a radius 1.8 times solar, and is 29 times more luminous than the Sun. The star is radiating an excess emission of infrared, which indicates the presence of a circumstellar disk of dust in its orbit.

11. Marfik – λ Ophiuchi (Lambda Ophiuchi)

Lambda Ophiuchi is a binary star in Ophiuchus. It has a combined apparent magnitude of 3.90 and is about 170 light years distant from the solar system. The star’s traditional name, Marfik, means “the elbow” in Arabic.

Lambda Ophiuchi is a suspected variable. It has the stellar classification of A0V+A, matching the spectrum of a white main sequence dwarf.

12. 67 Ophiuchi

67 Ophiuchi is a blue-white supergiant with the stellar classification of B5Ib. It has an apparent magnitude of 3.93 and an absolute magnitude of -4.26. The star is approximately 1,400 light years distant from Earth. It is a member of the open cluster Collinder 359.

13. 70 Ophiuchi

70 Ophiuchi is a binary star in Ophiuchus. It is only 16.58 light years distant from the Sun. The primary component in the system is an orange dwarf with the stellar classification of K0V. It has an apparent magnitude of 4.03. It is classified as a BY Draconis type variable, a star showing variations in brightness as a result of rotation coupled with star spots and other chromospheric activity.

The companion is another orange dwarf. It belongs to the spectral class K4V and has an apparent magnitude of 6.00. The two stars have an orbital period of 88.3 years.

14. χ Ophiuchi (Chi Ophiuchi)

Chi Ophiuchi has the stellar classification of B2Vne. It is a Be star, a star that radiates emissions from hydrogen which are indicative of a circumstellar ring of gas. It has an apparent magnitude that ranges from 4.18 to 5.0 and is classified as a Gamma Cassiopeiae type variable.

The star has a mass 10.1 times that of the Sun and a radius 4.5 times solar. It is 200,000 times more luminous than the Sun. Its estimated age is 22.5 million years.

15. 36 Ophiuchi

36 Ophiuchi is a triple star system only 19.5 light years from Earth. The three stars have apparent magnitudes of 5.29, 5.33 and 6.34. All three are orange dwarfs and have stellar classifications of K0 V, K1 V, and K5 V. The primary and secondary components are separated by 4.6 seconds of arc, and the tertiary star is separated from the main pair by 700 arc seconds. The third component is classified as an RS Canum Venaticorum variable, a close binary star with an active chromosphere that can cause large stellar spots, which in turn cause variations in brightness.

16. 51 Ophiuchi

51 Ophiuchi is a blue-white giant star belonging to the stellar class B9.5IIIe. It has a visual magnitude of 4.81 and is approximately 410 light years distant from the solar system. The star has a disk of dust that seems to be a young debris disk, likely a planetary system entering the last stage of planet formation.

17. 12 Ophiuchi

12 Ophiuchi is an orange main sequence dwarf with the stellar classification of K2V. It has an apparent magnitude of 5.77 and is 31.8 light years distant from the Sun. It is classified as a BY Draconis type variable.

12 Ophiuchi has 91 percent of the Sun’s mass, 84 percent of the solar radius, and only 39 percent of the Sun’s luminosity. It was one of the top 100 target stars for the Terrestrial Planet Finder mission before the mission was postponed indefinitely.

18. Barnard’s Star

Barnard’s Star is a red dwarf with the stellar classification of M4Ve. It has a visual magnitude of 9.54 and is only 5.980 light years distant from Earth. It is the fourth closest known individual star to the Sun. The only known stars that are closer to us are the three components of the Alpha Centauri system in Centaurus constellation. The star is too faint to be seen without a telescope.

Barnard’s Star was named after the American astronomer E. E. Barnard, who was the first to measure the star’s proper motion in 1916. The star has the largest proper motion of any star relative to the Sun, 10.3 arc seconds per year. Around the year 9,800, the star will make its closest approach to the Sun and come within 3.75 light years.

Barnard’s Star has an estimated age of 7 to 12 billion years. Despite its age, the star has been seen exhibiting an intense stellar flare, in 1998, which earned it the classification as a flare star. It is also classified as a BY Draconis variable.

The planet GJ 1214b, shown here in an artist’s conception with two hypothetical moons, orbits a “red dwarf” star 40 light-years from Earth. GJ 1214b has a radius of about 2.7 times that of Earth and is about 6.5 times as massive, putting it squarely into the class of exoplanets known as super-Earths. An exoplanet is a planet that orbits a star beyond our sun. Image: CfA, David Aguilar; source: NASA.gov

19. GJ 1214

GJ 1214 is a red dwarf with the stellar classification of M4.5.

It has a visual magnitude of 14.71 and is 47.5 light years distant from Earth.

The star has only 15.7 percent of the Sun’s mass and 20 percent of the solar radius.

A transiting extrasolar planet was discovered orbiting the star in December 2009.

The planet has 6.55 Earth masses and completes an orbit around the star every 1.58 days.

20. Wolf 1061

Wolf 1061 is another red dwarf located near the solar system. It is 13.82 light years distant and has an apparent magnitude of 10.10.

The star belongs to the spectral class M3 V.

Mythology

Ophiuchus is most frequently associated with the Greek mythical figure of Asclepius, son of the god Apollo, who was said to be able to bring people back from the dead with his healing powers. Asclepius learned how to do this after seeing one snake bringing healing herbs to another. This happened when Glaucus, the son of King Minos of Crete, fell into a jar of honey and drowned. Asclepius saw a snake slithering toward his body and killed it. Then another snake came along and placed a herb on the first one, which miraculously brought the first snake back to life. Asclepius saw this and took the same herb and placed it on Glaucus’ body. The king’s son was miraculously resurrected.

Asclepius was raised by Chiron, the wise centaur, associated with Centaurus constellation, who taught him the art of healing. In one of the myths, Asclepius was given the blood of the Gorgon Medusa by the goddess Athene. The Gorgon’s blood from the veins on her left side was poison, but the blood from the veins on the right side was said to be able to bring people back to life.

In another tale, Asclepius resurrected Theseus’ son Hippolytus after the king’s son was thrown from his chariot. In this version of the myth, Hippolytus is associated with Auriga constellation, the charioteer.

The healer was killed by Zeus because the god was worried that the human race would become immortal with Asclepius around to heal them. Zeus’ brother Hades, the god of the Underworld, was concerned that the flow of dead souls into his domain would dry up as a result of Asclepius’ healing ability. Hades complained about this to Zeus and the thunder god killed the healer with a bolt of lightning. Zeus later placed Asclepius’ image in the sky to honour his gift and good deeds. The healer became the constellation Ophiuchus, the Serpent Bearer.

Ophiuchus constellation may be descended from an ancient Babylonian constellation that represented the serpent-god Nirah, who was sometimes depicted as a hybrid being, with a human head and torso, and serpents for legs. This theory, however, has not been confirmed by sufficient evidence.

The constellation got a notable mention in John Milton’s Book 2 of Paradise Lost, in which Satan was compared to a comet “that fries the length of Ophiuchus huge/In th’ arctic sky.”

Reference:

https://www.pinterest.co.uk/explore/ophiuchus-constellation/

https://www.mindbodygreen.com/0-26952/everything-you-need-to-know-about-the-new-zodiac-sign-the-astrotwins-explain.html

http://earthsky.org/tonight/ophiuchus-highest-on-august-evenings-2

http://www.constellation-guide.com/constellation-list/ophiuchus-constellation/