Using binoculars or small binoculars, we can see that Aurelius I is a pair of binary stars, and the angular distance between the two stars in the sky is 3.5 arc minutes. In fact, the distance is at least 265,438+0,000 astronomical units (0.34 light years), and it takes about 700,000 years to circle each other. The brighter of the two is Capricorn β 1, and the apparent magnitude is+3.05; The darker one is Capricorn β2 with an apparent magnitude of +6.09. These two stars are themselves multi-star systems.
Due to the complexity of this system, there are several different observations about the composition of this system. This paper adopts the names in the multi-star table.
The brighter companion star Capricorn β 1 is a complex group with at least three members, and its spectrum is difficult to understand. It is controlled by a pair of stars. The orange K-shaped bright giant is called Capricorn β Aa, and its apparent magnitude is +3.08. Blue and white B Capricorn β Ab apparent magnitude +7.20, etc. The two stars are separated by 0.05 arc seconds (5 astronomical units) and have an orbital period of 3.77 days.
Capricorn β Aa has a surface temperature of 4,900K, a diameter of 35 times that of the sun and a brightness of 600 times that of the sun. Capricorn β Ab also has an invisible companion, Capricorn β Ac, which surrounds Capricorn β Ab with an orbital period of 8.7 days. Capricorn β Aa itself is considered as a multi-star system.
The darker visual binary Capricorn β2 is simpler and more studied. It is a conjoined star, and its bright companion is called Capricorn β B, with brightness of 6. 1, etc. It is an A0 giant star, and its brightness is 40 times that of the sun. Its companion star Capricorn β C is 3 seconds away from us. Capricorn β B is an abnormal star, and the atmosphere contains a lot of mercury and manganese.
John Herschel discovered two other nearby stars, which are arc seconds away from Capricorn β 11,but he was not sure whether they were simple optical binaries or part of Capricorn β1system. Sometimes these two stars are called Capricorn β D and Capricorn β E ... Hegu II is the second star of Hegu Star, namely Altair, also called Petunia or General, commonly known as Altair.
The 12th bright star in the whole day, white, with magnitude of 0.77 and distance of 16.3 light years. The luminosity is about 8 times that of the sun, and the surface temperature is about 7000 degrees Celsius. Its connection with beta and gamma stars of Aquila points to Vega.
Location: Right ascension 19: 48.3 and 8: 44 declination. Vega I, a famous Vega, is also called Tiansun, because Vega is the granddaughter of Tiandi in the myth of "Cowherd and Weaver Girl" in ancient China.
Vega is the brightest star in Lyra (Alpha Lyra) and the fifth brightest star in the whole day, second only to arcturus. In summer in the northern hemisphere, Vega can be seen near the zenith, 25.3 light years away from the earth. Because the apparent magnitude of Vega is close to zero, many professional astronomers will use Vega as the standard for photometric determination.
Vega, Tsukuya II (Altair) in the eagle and Tianjin IV in Cygnus form the famous "Summer Triangle". If you think of it as a right triangle, Vega is a star that forms a right angle.
The spectral classification of Vega is A0V, and the temperature is a little higher than Sirius A1V.. It is still in the main sequence star stage, emitting light and heat by condensing hydrogen in the core into helium. In addition, the mass of Vega is 2.5 times that of the sun. The higher the mass of a star, the faster it consumes fuel and releases 50 times the energy of the sun every second, so Vega's life span is only 65.438+billion years, which is one tenth of the life span of the sun. It is determined that Vega rotates once every 12.5 hours, the whole star is flat, and the equatorial diameter ratio is 23%.
Because the celestial pole of the celestial sphere will shift due to precession, Vega will become the north star around AD 14000.
In the1980s, IRAS satellite found that Vega was surrounded by a dust disk. This dust disk was originally considered as a protoplanetary disk, but now it is considered as a "debris disk" because Vega itself is still very young, only 200 million years old. 1998, the UCLA Joint Astronomical Center detected some unusual places in the dust disk, pointing out that there may be planets in Vega. In 2003, a paper put forward this hypothesis, arguing that these unusual discoveries may be caused by the orbital migration of a planet similar to Neptune within 56 million years, and its orbital daily distance moved from 40 AU to 65 AU, which provided an environment for the formation of terrestrial planets. These hypotheses have yet to be confirmed, but because Vega's heat is much stronger than that of the sun, scientists believe that there must be no life on the planets in the inner region. Cygnus β (middle name of chariot plus seven) is the third bright star of Cygnus. Although its brightness is ranked second in Bayer nomenclature, it is actually darker than cygnus γ.
The image of Cygnus is "a swan", and Cygnus β is located in the head of the swan, so Cygnus β is sometimes called "beak star". Cygnus β, Cygnus α (Tianjin IV), Cygnus δ and Cygnus η * * together form the "Northern Cross".
The English name Albireo of this star originated from misinformation and mistranslation. Its original name is Al-Minhar Al-Dajiajah, which comes from the Arabic word "hen's mouth". Latin scholars misunderstood it and thought that its name came from an herb, so it was translated into ab ireo ("from ireus"). Later, people thought it was a misprint in Arabic, so they changed their name to al-bireo.
Cygnus beta is 385 light years away from the earth. Cygnus beta is a single star observed with the naked eye. But in fact, with the help of binoculars or astronomical telescopes, the so-called cygnus β is actually a binary star, one is yellow (apparent magnitude 3. 1) and the other is blue (apparent magnitude 5. 1). Seen from the earth, the distance is 34 arc seconds. Because the colors of the two sub-stars are just complementary, they are the most prominent binary stars in the whole day.
People used to think that they were just optical binaries, and they had nothing in common, and they were orbiting like real binary systems. In any case, although they are far apart, they are generally considered to be true binary stars.
Of the two stars, the yellow star Cygnus βA is brighter, and it is a close binary star.