The group also includes Antares in Scorpius, Enif and Markab in Pegasus, Altair in Aquila, Rasalhague and Sabik in Ophiuchus, Spica in Virgo, and Nunki in Sagittarius.Īlphecca is an outlying member of the Ursa Major Moving Group (Collinder 285), a stellar association that includes most of the bright stars of the Big Dipper – Alioth, Mizar and Alcor, Phecda, Merak and Megrez – as well as Menkalinan in the constellation Auriga, Skat in Aquarius, Adhafera in Leo, Gamma Leporis in Lepus, Beta Serpentis in Serpens, and Zeta Boötis in Boötes. It is part of a group of 13 navigational stars located in the equatorial region of the western celestial hemisphere. It is the only navigational star in Corona Borealis. 4.96).Īlphecca is one of the 58 bright stars that have a special status in the field of celestial navigation. 4.57 – 4.69), Epsilon Coronae Borealis (mag. 3.65 – 3.72), Theta Coronae Borealis (mag. Representing the crown of Ariadne, the asterism is formed by Alphecca, Nusakan (Beta Coronae Borealis, mag. FactsĪlphecca is the brightest of the seven stars that form the crown-shaped pattern of Corona Borealis. The star has an estimated rotational velocity of less than 14 km/s and a rotation period of 7 to 9 days. With a surface temperature of 5,800 K, it shines with 0.81 solar luminosities. The star is slightly smaller and less massive than the Sun, with a size of 0.90 solar radii and mass of 0.92 solar masses. The secondary component in the Alpha Coronae Borealis system is a yellow main sequence star with the stellar classification G5V. A study published in 2014 estimated a radius of 61 astronomical units for the disk. The star’s estimated age is 314 million years.Īlphecca (Alpha Coronae Borealis), image: WikiskyĪ survey with the Infrared Astronomical Satellite (IRAS) in 2006 revealed excess emission in the infrared, indicating the presence of a debris disk around the star in which planets and protoplanetary systems may form. It is a fast spinner, with a projected rotational velocity of 139 km/s. With an effective temperature of 9,700 K, the star is 74 times more luminous than the Sun. It has a mass 2.58 times that of the Sun and a radius between 2.89 and 3.04 times solar. The primary component in the system is the white, class A0 main sequence star. The amplitude of the variations is too small to be noticed by the unaided eye. The eclipses cause the system’s brightness to vary from magnitude 2.21 to 2.32. The orbit is inclined at an angle of 88.2° to our line of sight and, as a result, we see the stars eclipse each other as they orbit. During their orbit, the stars come within 0.13 astronomical units of each other and go as far apart as 0.27 astronomical units. The average distance between the stars is 0.20 astronomical units. Star systemĪlpha Coronae Borealis is an eclipsing binary system consisting of two main sequence stars of the spectral types A0V and G5V that orbit each other with a period of 17.3599 days and an eccentricity of 0.370. Alphecca has an average apparent magnitude of 2.23 and lies at an approximate distance of 75 light years from Earth. Ariadne’s crown is represented by a semicircle of relatively bright stars that gives Corona Borealis its name. Also known as Gemma, Alpha CrB is an eclipsing binary star system that marks the jewel in the crown of the Greek mythical princess Ariadne. Alphecca, Alpha Coronae Borealis (α CrB), is the brightest star in the constellation Corona Borealis, the Northern Crown.
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