The Saudi sky is witnessing the conjunction of “The Hunchback of Dhul Qa’dah” with the summer star


Abu Zahra: The red color of Antares indicates its low surface temperature

The head of the Astronomical Society in Jeddah, Eng. Majed Abu Zahra, stated that the sky of Saudi Arabia and the Arab world will witness, after sunset today, Tuesday, June 22, 2021 and the beginning of the night, the conjunction of the growing humpback moon with the summer star Antares Scorpio towards the southern horizon in a phenomenon seen with the naked eye.

He added: Antares is a striking star that shimmers with a distinctive red glow in the summer nights in the northern hemisphere. It is a huge red giant star with a mass of 15 to 18 times the mass of the sun and a radius of more than 448,793,612 kilometers. Its surface would extend beyond the orbit of Mars, and unlike red dwarf stars, giant stars have short lifespans by stellar standards.

He continued: Antares is only about 12 million years old, yet it is in its autumn, unlike the Sun, which is 4 and a half billion years old, which is its average age.

He said: The red color of Antares refers to its low surface temperature of about 3,200 degrees Celsius, in contrast to the sun’s surface temperature of 5,700 degrees Celsius, which is yellow. bluish which is characterized by a surface temperature of about 22,100 °C.

He said: Most of the red-colored stars are not visible to the naked eye because they are small and faint red dwarf stars. The cold red dwarf stars are only a fraction of the size and luminosity of the Sun, but they are believed to make up about 70% of the stars in our Milky Way.

These red dwarfs are extremely long-lived stars with a life span of about a trillion years.

He pointed out that the red stars that can be seen with the naked eye are rather rare, in fact, all the bright red stars that we see in the night sky with the naked eye are either red giants (such as the star Aldebaran) or red giants (such as the stars Antares and Betelgeuse).

He continued: “Red giant stars are rare, as they represent about one in every million stars in our galaxy, the Milky Way. Nearly 10 red giant stars can be seen with the naked eye in a dark sky. The large size of these stars above the red giant makes them bright, despite Being somewhat far away, for example, it is believed that Antares is located at a distance of about 550 light-years, but this star has a luminosity of the first magnitude.

Sabq electronic newspaper


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