Aries constellation is located in the northern hemisphere. Its name means ‘ram’ in Latin. Aries is the 39th largest constellation in the sky, occupying 441 square degrees. It lies in the first quadrant of the northern hemisphere (NQ1) and can be seen at latitudes between +90° and -60°. The neighboring constellations are Cetus, Perseus, Pisces, Taurus, and Triangulum.
[http://www.constellation-guide.com/constellation-list/aries-constellation/]
In astrology, Aries is the first astrological sign in the Zodiac, spanning the first 30 degrees of celestial longitude. Under the tropical zodiac, the Sun transits this sign mostly between March 20 and April 19 each year. Under the sidereal zodiac, the sun currently transits Aries approximately from April 15 to May 14. The symbol of the ram (♈) is based on the Chrysomallus, the flying ram that provided the Golden Fleece.
According to the Tropical system of astrology, the Sun enters the sign of Aries when it reaches the northern vernal equinox, which occurs around March 21. Because the Earth takes approximately 365.25 days to go around the Sun, the precise time of the equinox is not the same each year, and generally will occur about 6 hours later each year, with a jump of a day (backwards) on leap years. Since 1900 the vernal equinox date ranged from March 20 at 08h (2000) to March 21 at 19h (1903). March 19 at 23:20 will occur in 2044. (All times UTC.)
[https://en.wikipedia.org/wiki/Aries_(astrology)]
Astrologically, Aries has been associated with the head and its humors. It was strongly associated with Mars, both the planet and the god. The First Point of Aries, the location of the vernal equinox, is named for the constellation. This is because the Sun crossed the celestial equator from south to north in Aries more than two millennia ago. Hipparchus defined it in 130 BCE as a point south of Gamma Arietis. Because of the precession of the equinoxes, the First Point of Aries has since moved into Pisces and will move into Aquarius by around 2600 AD. The Sun now appears in Aries from late April through mid-May, though the constellation is still associated with the beginning of spring.
Chart of the Constellation Aries. From John Flamsteed’s Atlas Coelestis. (1729)
[http://www.booktryst.com/2010/07/aussie-atlas-reaches-for-stars.html]
In the description of the Babylonian zodiac given in the clay tablets known as the MUL.APIN, the constellation now known as Aries was the final station along the ecliptic. The MUL.APIN was a comprehensive table of the risings and settings of stars, which likely served as an agricultural calendar. Modern-day Aries was known as MULLÚ.ḪUN.GÁ, ‘The Agrarian Worker’ or ‘The Hired Man.’ Although likely compiled in the 12th or 11th century BCE, the MUL.APIN reflects a tradition which marks the Pleiades as the vernal equinox, which was the case with some precision at the beginning of the Middle Bronze Age. The earliest identifiable reference to Aries as a distinct constellation comes from the boundary stones that date from 1350 to 1000 BCE. On several boundary stones, a zodiacal ram figure is distinct from the other characters present. The shift in identification from the constellation as the Agrarian Worker to the Ram likely occurred in later Babylonian tradition because of its growing association with Dumuzi the Shepherd. By the time the MUL.APIN was created- by 1000 BCE- modern Aries was identified with both Dumuzi’s ram and a hired laborer. The exact timing of this shift is difficult to determine due to the lack of images of Aries or other ram figures.
In ancient Egyptian astronomy, Aries was associated with the god Amon-Ra, who was depicted as a man with a ram’s head and represented fertility and creativity. Because it was the location of the vernal equinox, it was called the ‘Indicator of the Reborn Sun.’ During the times of the year when Aries was prominent, priests would process statues of Amon-Ra to temples, a practice that was modified by Persian astronomers centuries later. Aries acquired the title of ‘Lord of the Head’ in Egypt, referring to its symbolic and mythological importance.
In Hellenistic astrology, the constellation of Aries is associated with the golden ram of Greek mythology that rescued Phrixos and Helle on orders from Hermes, taking him to the land of Colchis. Phrixos and Helle were the son and daughter of King Athamas and his first wife Nephele. The king’s second wife, Ino, was jealous and wished to kill his children. To accomplish this, she induced a famine in Boeotia, then falsified a message from the Oracle of Delphi that said Phrixos must be sacrificed to end the famine. Athamas was about to sacrifice his son atop Mount Laphystium when Aries, sent by Nephele, arrived. Helle fell off of Aries’s back in flight and drowned in the Dardanelles, also called the Hellespont in her honor. After arriving, Phrixos sacrificed the ram to Zeus and gave the Fleece to Aeëtes of Colchis, who rewarded him with an engagement to his daughter Chalciope. Aeëtes hung its skin in a sacred place where it became known as the Golden Fleece and was guarded by a dragon. In a later myth, this Golden Fleece was stolen by Jason and the Argonauts.
Historically, Aries has been depicted as a crouched, wingless ram with its head turned towards Taurus. Ptolemy asserted in his Almagest that Hipparchus depicted Alpha Arietis as the ram’s muzzle, though Ptolemy did not include it in his constellation figure. Instead, it was listed as an ‘unformed star,’ and denoted as ‘the star over the head.’ John Flamsteed, in his Atlas Coelestis, followed Ptolemy’s description by mapping it above the figure’s head. Flamsteed followed the general convention of maps by depicting Aries lying down.
Medieval Muslim astronomers depicted Aries in various ways. Astronomers like al-Sufi saw the constellation as a ram, modeled on the precedent of Ptolemy. However, some Islamic celestial globes depicted Aries as a nondescript four-legged animal with what may be antlers instead of horns. Some early Bedouin observers saw a ram elsewhere in the sky; this constellation featured the Pleiades as the ram’s tail. The generally accepted Arabic formation of Aries consisted of thirteen stars in a figure along with five ‘unformed’ stars, four of which were over the animal’s hindquarters and one of which was the disputed star over Aries’s head. Al-Sufi’s depiction differed from other Arab astronomers’, in that his Aries was running and looking behind itself.
In traditional Chinese astronomy, stars from Aries were used in several constellations. The brightest stars- Alpha, Beta, and Gamma Arietis- formed a constellation called Lou, variously translated as ‘bond,’ ‘lasso,’ and ‘sickle,’ which was associated with the ritual sacrifice of cattle. This name was shared by the 16th lunar mansion, the location of the full moon closest to the autumnal equinox. The lunar mansion represented the area where animals were gathered before sacrifice around that time. This constellation has also been associated with harvest-time as it could represent a woman carrying a basket of food on her head.
In a similar system to the Chinese, the first lunar mansion in Hindu astronomy was called ‘Aswini,’ after the traditional names for Beta and Gamma Arietis, the Aswins. Because the Hindu New Year began with the vernal equinox, the Rig Veda contains over 50 new-year’s related hymns to the twins, making them some of the most prominent characters in the work. Aries itself was known as ‘Aja’ and ‘Mesha.’
In Hebrew astronomy Aries was named ‘Teli;’ it signified either Simeon or Gad, and generally symbolizes the ‘Lamb of the World.’ The neighboring Syrians named the constellation ‘Amru,’ and the bordering Turks named it ‘Kuzi.’
Half a world away, in the Marshall Islands, several stars from Aries were incorporated into a constellation depicting a porpoise, along with stars from Cassiopeia, Andromeda, and Triangulum. Alpha, Beta, and Gamma Arietis formed the head of the porpoise, while stars from Andromeda formed the body and the bright stars of Cassiopeia formed the tail. Other Polynesian peoples recognized Aries as a constellation. The Marquesas islanders called it Na-pai-ka; the Maori constellation Pipiri may correspond to modern Aries as well.
In indigenous Peruvian astronomy, a constellation with most of the same stars as Aries existed. It was called the ‘Market Moon’ and the ‘Kneeling Terrace,’ as a reminder for when to hold the annual harvest festival, Ayri Huay.
Bright Stars and Deep-Sky Objects in Aries, Taurus, Gemini and surrounding Constellations
[http://www.nakedeyeplanets.com/zodiac-constellations/ari-tau-gem.htm]
The Aries constellation and nearby Deep Sky Objects
[http://www.universetoday.com/19603/aries/]
Aries has three prominent stars forming an asterism, designated Alpha, Beta, and Gamma Arietis. All three are commonly used for navigation. There is also one other star above the fourth magnitude, 41 Arietis.
Alpha Arietis is the brightest star in the constellation of Aries. The name Hamal derives from the Arabic ‘rās al-ħamal,’ ‘head of the ram,’ in turn from the name for the constellation as a whole, ‘al Ħamal,’ ‘the ram.’ With an apparent visual magnitude of 2.0, Hamal is among the brightest stars in the night sky. It is about 65.8 light-years (20.2 parsecs) from Earth. It is a giant star that may host an orbiting planet with a mass greater than Jupiter.
The spectrum of this star matches a stellar classification of K2 III Ca-1, with the luminosity class of III indicating that it is an evolved giant star that has exhausted the supply of hydrogen at its core and is now on the red giant branch. The ‘Ca-1’ portion of the classification indicates that it shows weaker than normal lines of calcium in its spectrum. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It is estimated to have about 50% more mass than the Sun, while interferometric measurements show it to be 15 times larger in diameter. Despite its enlarged girth, this star is still spinning with a slightly faster equatorial azimuthal velocity than the Sun, having a projected rotational velocity of 3.44 km s−1.
Hamal is radiating about 91 times the Sun’s luminosity from its outer envelope at an effective temperature of 4,480 K. This is cooler than the surface of the Sun, giving it the orange-hued glow of a K-type star. It is suspected to be slightly variable, with an amplitude of 0.06 magnitude. The abundance of elements other than hydrogen and helium, what astronomers term the stars metallicity, is only around half that in the Sun.
In 2011, the likely presence of a planet in orbit around this star was reported. The object has an orbital period of 381 days and an eccentricity of 0.25. The lower bound on this object’s mass is about 1.8 times the mass of Jupiter. The estimated semi-major axis of the planet’s orbit is 1.2 astronomical units (AU). By comparison, the star has a radius of 0.07 AU.
[https://en.wikipedia.org/wiki/Hamal]
Beta Arietis has the traditional name Sheratan (or Sharatan, Sheratim), which is derived from the Arabic ‘aš-šarāţān, ‘the two signs,’ a reference to the star having marked the northern vernal equinox together with Gamma Arietis several thousand years ago.
Beta Arietis has an apparent visual magnitude of 2.66. It is located at a distance of 59.6 light-years (18.3 parsecs) from Earth. This is a spectroscopic binary star system consisting of a pair of stars orbiting around each other with a highly elliptical orbit every 107 days. The primary star has a stellar classification of A5 V, which means it is an A-type main sequence star that is generating energy through the thermonuclear fusion of hydrogen in its core region. The spectrum of the secondary star has not been determined, but, based on the mass, it may have a stellar classification of F5 III–V or G0 V. It is about four magnitudes fainter than the primary; hence the energy output from the system is dominated by the primary star. In a few million years, as the primary evolves toward a red giant, significant amounts of mass transfer to the secondary component is expected.
[https://en.wikipedia.org/wiki/Beta_Arietis]
41 Arietis is a binary star and the third brightest in the constellation of Aries. It does not possess a Greek letter Bayer designation, since this star was once part of the now-obsolete constellation Musca Borealis, but is sometimes designated c Arietis. With an apparent visual magnitude of 3.63, this star is readily visible to the naked eye. The distance to this star is 166 light-years (51 parsecs).
The primary component is a B-type main sequence star with a stellar classification of B8 Vn. The suffix ‘n’ indicates ‘nebulous’ absorption lines in the star’s spectrum caused by the Doppler effect of rapid rotation. It has a projected rotational velocity of 175 km/s. This is creating an equatorial bulge that is 12% large than the star’s polar radius. It has an orbiting companion at an angular separation of 0.3 arcseconds.
[https://en.wikipedia.org/wiki/41_Arietis]
Gamma Arietis has the traditional name Mesarthim, which may be from the Hebrew word ‘mᵋshārᵋtīm,’ meaning ‘the minister,’ or from the Arabic word ‘al muthartim,’ meaning ‘the ram.’ It is a binary star, and the combined apparent visual magnitude of the two stars is 3.86, which is readily visible to the naked eye and makes this the fourth brightest member of Aries. The distance to Gamma Arietis is approximately 164 light-years (50 parsecs).
The two components have an angular separation of 7.606 arcseconds, which can be resolved with a small telescope. The orbital period of the pair is greater than 5000 years. The brighter component, γ¹ Arietis, is a magnitude 4.58 B-type main sequence star with a stellar classification of B9 V. The secondary, γ² Arietis, is a Lambda Boötis (chemically peculiar) star with a stellar classification of A1p Si and a magnitude of 4.64. It is classified as an α2 CVn type variable star and its brightness varies by 0.04 magnitudes with a period of 2.61 days.
[https://en.wikipedia.org/wiki/Gamma_Arietis]
Teegarden’s Star
[https://jumk.de/astronomie/near-stars/teegardens-star.shtml]
Teegarden’s Star (SO J025300.5+165258) is an M-type red dwarf in the constellation Aries, located about 12 light years from the Solar System. Despite its proximity to Earth it is a dim magnitude 15 and can only be seen through large telescopes. This star was found to have a very large proper motion of about 5 arcseconds per year. Only seven stars with such large proper motions are currently known.
Teegarden’s Star was discovered in 2003 using asteroid tracking data that had been collected years earlier. This data set is a digital archive created from optical images taken over a 5-year period by the Near Earth Asteroid Tracking (NEAT) program using two 1-m telescopes located on the Hawaiian Island of Maui. The star is named after the discovery team leader, Bonnard J. Teegarden, an astrophysicist at NASA’s Goddard Space Flight Center.
Astronomers have long thought it was quite likely that many undiscovered dwarf stars exist within 20 light years of Earth, because stellar-population surveys show the count of known nearby dwarf stars to be lower than otherwise expected and these stars are dim and easily overlooked. Teegarden’s team thought that these dim stars might be found by data mining some of the huge optical sky survey data sets taken by various programs for other purposes in previous years. So they reexamined the NEAT asteroid tracking data set and found this star. The star was then located on photographic plates from the Palomar Sky Survey taken in 1951. This discovery is significant as the team did not have direct access to any telescopes and did not include professional astronomers at the time of the discovery.
Teegarden’s Star is identified as a red dwarf, but with a mass of 0.08 times that of the Sun it is just above the upper limit of objects classified as brown dwarfs. The inherent low temperatures of such objects explain why it was not discovered earlier, since it has an apparent magnitude of only 15.4 (and an absolute magnitude of 17.47). Like most red and brown dwarfs it emits most of its energy in the infrared spectrum.
The parallax was initially measured as 0.43 ± 0.13 arcseconds. This would have placed its distance at only 7.50 light years, making Teegarden’s Star only the third star system in order of distance from the Sun, ranking between Barnard’s Star and Wolf 359. A more accurate parallax measurement of 0.2593 arcseconds was made in 2009, yielding the now accepted distance of 12.578 light years.
[https://en.wikipedia.org/wiki/Teegarden%27s_star]
Planetary orbits of the HD 12661 system
HD 12661 is a G-type main sequence star in the constellation of Aries. The star is slightly larger and more massive than the Sun, with an estimated age of seven billion years. It has two known extrasolar planets.
The apparent visual magnitude of this star is 7.42, making it too faint to be viewed by the naked eye even under ideal viewing conditions. However, it can be readily observed using a small telescope. It is located at a distance of about 114 light-years (35 parsecs) from the Earth. It has a stellar classification of G6 V, indicating that it is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. The effective temperature of the star’s outer envelope is about 5,754 K, giving it the characteristic yellow hue of a G-type star. Based on stellar models, estimates of the radius of this star range from 107% to 112% times Sun’s radius, while the mass is likely in the range from 107% to 110% of the Sun’s mass.
The first planet was discovered in 2001 from the Lick and Keck observatories using precision measurements of the star’s radial velocity variations. The periodicity in this variation allowed astronomers to extract information about the planet’s orbit and minimum mass. A second planet was discovered by the same team two years later. Both planets are greater in mass than Jupiter.
[https://en.wikipedia.org/wiki/HD_12661]
The few deep-sky objects in Aries are very dim. Nevertheless, several scientifically interesting galaxies lie within its borders; NGC 772 is a spiral galaxy with an integrated magnitude of 10.3, located southeast of β Arietis. It is a relatively bright galaxy and shows obvious nebulosity and ellipticity in an amateur telescope. The main arm, on the northwest side of the galaxy, is home to many star forming regions. The companion galaxy, NGC 770, is about 113,000 light-years away from the larger galaxy. NGC 772 has a diameter of 240,000 light-years, and the system is 114 million light-years from Earth:
Arp 78: Peculiar Galaxy in Aries
Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries, some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy. Also known as NGC 772, the island universe is over 100 thousand light-years across and sports a single prominent outer spiral arm in this detailed cosmic portrait. Its brightest companion galaxy, compact NGC 770, is toward the upper right of the larger spiral. NGC 770’s fuzzy, elliptical appearance contrasts nicely with a spiky foreground Milky Way star in matching yellowish hues. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78’s large spiral arm is likely due to gravitational tidal interactions. Faint streams of material seem to connect Arp 78 with its nearby companion galaxies.
[http://apod.nasa.gov/apod/ap110707.html]
Arp 276 is a pair of interacting galaxies in Aries, consisting of NGC 935 and IC 1801:
Galactic Train Wreck
This image shows an example of colliding galaxies from a new photo atlas of galactic ‘train wrecks.’ The new image combine observations from NASA’s Spitzer Space Telescope, which observes infrared light, and NASA’s Galaxy Evolution Explorer (GALEX) spacecraft, which observes ultraviolet light. By analyzing information from different parts of the light spectrum, scientists can learn much more than from a single wavelength alone, because different components of a galaxy are highlighted.
The image shows NGC 935 and IC 1801. In this representative-color image, far-ultraviolet light from GALEX is blue, 3.6-micron light from Spitzer is cyan, 4.5-micron light from Spitzer is green, and red shows light at 5.8 and 8 microns from Spitzer.
Distance: 180,000,000 Light Years
[http://www.spitzer.caltech.edu/images/3614-sig11-005c-Galactic-Train-Wreck]
Appearance of the eastern sky at 5:00 am on June 7, 2000 from a mid-northern latitude observing site.
[https://en.wikipedia.org/wiki/Arietids]
Aries is home to several meteor showers. The Daytime Arietid meteor shower is one of the strongest meteor showers that occurs during the day, lasting from 22 May to 2 July. It is an annual shower associated with the Marsden group of comets that peaks on 7 June with a maximum zenithal hourly rate of 54 meteors. Its parent body may be the asteroid Icarus. The meteors are sometimes visible before dawn, because the radiant is 32 degrees away from the Sun. They usually appear at a rate of 1-2 per hour as ‘earthgrazers,’ meteors that last several seconds and often begin at the horizon.
[https://en.wikipedia.org/wiki/Aries_(constellation)]
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