1. Introduction

Aries, an iconic constellation in the northern celestial hemisphere, holds a storied place in both ancient mythology and modern astronomy. Recognized by the International Astronomical Union (IAU), Aries is one of the twelve zodiac constellations, tracing its origins to ancient civilizations' interpretations of the heavens.

Situated between the constellations Pisces and Taurus, Aries occupies a region of the sky known for its rich celestial offerings and significant astronomical phenomena. Its celestial coordinates lie approximately between right ascension 02h 00m to 03h 30m and declination +10° to +30°, placing it within the realm of the northern celestial hemisphere (Figure 1).

In Greek mythology, Aries represents the golden ram that played a pivotal role in the tale of Jason and the Argonauts. According to legend, the ram was sent by the god Hermes to rescue Phrixus and his sister Helle, carrying them to safety across the sea. To honor its divine intervention, Phrixus sacrificed the ram and presented its golden fleece to King Aeëtes, initiating the famous quest of Jason and the Argonauts.

Astronomically, Aries holds significance as the location of the vernal equinox, marking the beginning of spring in the northern hemisphere. This celestial event occurs when the Sun crosses the celestial equator, transitioning from the southern to the northern hemisphere. As such, Aries serves as a celestial marker for the changing seasons, heralding the renewal of life and the awakening of nature.

Figure 1. IAU chart of Aries. Source: https://www.iau.org/static/archives/images/screen/ari.jpg. Credit: IAU and Sky & Telescope. Reproduced under CC BY 4.0 license.

2. Historical Background

In ancient Mesopotamia, the region often regarded as the cradle of civilization, Aries was associated with the agrarian deity Dumuzid, also known as Tammuz. Dumuzid was considered a shepherd god, symbolizing the renewal of life and fertility, particularly in relation to agriculture. The constellation's appearance in the night sky was believed to herald the arrival of spring, marking the time for sowing and planting crops.

In ancient Egyptian astronomy, Aries was linked with the god Amon-Ra, the chief deity of the Egyptian pantheon associated with the sun and creation. Amon-Ra was often depicted as a ram or a ram-headed deity, symbolizing strength, power, and divine authority. The appearance of Aries in the eastern sky before sunrise was seen as a sign of the sun's rebirth and the renewal of life.

In Greek mythology, Aries is closely associated with the tale of Jason and the Argonauts and their quest for the Golden Fleece. According to legend, King Athamas of Boeotia was ordered by the god Hermes to sacrifice a ram with a golden fleece in order to save his kingdom from famine. Athamas's wife Nephele, who was a cloud nymph, gave birth to the winged ram with the golden fleece. The ram, known as Chrysomallus, later became the famous Golden Fleece that Jason and the Argonauts sought to retrieve.

Additionally, Aries is linked with the Greek god Hermes, who transformed himself into a ram to carry Phrixus and his sister Helle across the sea to safety. Phrixus and Helle were fleeing from their stepmother, Ino, who sought to harm them. During their journey, Helle fell from the ram's back and drowned in the sea, which later became known as the Hellespont (now the Dardanelles).

In ancient Babylonian astronomy, Aries was associated with the agrarian deity Adad, the god of storms and thunder. The appearance of Aries in the sky was believed to coincide with the arrival of spring rains, which were crucial for agricultural fertility and the prosperity of the land.

Throughout history, Aries has been recognized as a symbol of renewal, fertility, and divine protection across various cultures and civilizations. Its prominent position in the zodiacal belt and its association with the vernal equinox have made it a significant celestial marker for seasonal changes and agricultural activities. Today, while the mythological significance of Aries may have faded, its astronomical importance remains steadfast, serving as a point of reference for astronomers and navigators alike in their exploration of the cosmos.

3. Notable Stars in the Constellation Aries

3.1. Hamal (Alpha Arietis)

Hamal, also known as Alpha Arietis, is the brightest star in the constellation Aries. Classified as an orange giant star, Hamal shines with an apparent magnitude of about 2.0 and is visible to the naked eye under dark skies. Located approximately 65 light-years away from Earth, Hamal is notable for its spectral type K2III, indicating its advanced evolutionary stage as a giant star nearing the end of its life.

3.2. Sheratan (Beta Arietis)

Sheratan, designated Beta Arietis, is another notable star in Aries. It forms part of the distinctive "V" shape that marks the head of the ram in the constellation's visual representation. Sheratan is a binary star system composed of two main-sequence stars orbiting each other. The primary star, Sheratan A, is a spectral type A5V star, while the companion, Sheratan B, is a spectral type F7V star. This binary system is located approximately 59 light-years away from Earth.

3.3. Mesarthim (Gamma Arietis)

Mesarthim, also known as Gamma Arietis, is a binary star system located in Aries. It is one of the closest-known double stars to Earth, with an apparent magnitude of about 4.8. The primary star, Mesarthim A, is a spectral type A1V star, while the companion, Mesarthim B, is a spectral type A3V star. This binary system is approximately 162 light-years away from our solar system.

3.4. Botein (Delta Arietis)

Botein, designated Delta Arietis, is a yellow-orange giant star located in Aries. It has an apparent magnitude of about 4.3 and is approximately 168 light-years away from Earth. Botein is notable for its spectral type K2III, indicating its advanced evolutionary stage as a giant star. It is visible to the naked eye and contributes to the constellation's distinctive shape.

4. Deep-Sky Objects in the Constellation Aries

4.1. NGC 772 (Arp 78)

NGC 772, also known as Arp 78, is a beautiful barred spiral galaxy located in the constellation Aries. It is positioned approximately 130 million light-years away from Earth. The galaxy's distinctive feature is its asymmetric structure, with one spiral arm extending much farther than the other, likely due to gravitational interactions with neighboring galaxies. This interaction has also led to the creation of a long tidal tail stretching away from the galaxy. NGC 772 has a relatively bright nucleus and spiral arms adorned with regions of intense star formation, visible as bright knots and patches of blue. The galaxy's intricate structure makes it a popular target for amateur and professional astronomers alike. Despite its distance, NGC 772 is visible through moderate-sized telescopes under dark skies, offering a mesmerizing view of its cosmic splendor.

4.2. NGC 680

NGC 680 is a spiral galaxy located in the constellation Aries. It is classified as a spiral galaxy with an intermediate degree of winding in its arms. NGC 680 is positioned approximately 270 million light-years away from Earth. The galaxy exhibits a bright nucleus surrounded by fainter spiral arms that extend outward from the center.