Tag Archives: Alpha Centauri

Alpha Centauri is the star system closest to the Solar System. It is 4.37 light-years (1.34 pc) from the Sun. It consists of three stars: Alpha Centauri A and Alpha Centauri B, which form the binary star Alpha Centauri AB, and a small and faint red dwarf, Alpha Centauri C (also named Proxima Centauri), which is loosely gravitationally bound and orbiting the other two at a current distance of about 13,000 astronomical units (0.21 light-years). To the unaided eye, the two main components appear as a single point of light with an apparent visual magnitude of −0.27, forming the third-brightest star in the night sky, after Sirius and Canopus. An Earth-sized exoplanet in the habitable zone of Proxima Centauri, Proxima Centauri b, was discovered in 2016. How habitable Proxima b is unclear. It is so close to a red dwarf, habitability problems are already coming to scientists’ minds. For one thing, the planet is so close that it likely is tidally locked to the star, meaning that one side of the planet is always facing the star. This means one side of the planet would be very warm, while the opposite side would be very cold – unless winds could distribute the heat around the planet. That makes it hard for life to exist.

But the planet’s close distance to the red dwarf presents other problems too. Red dwarfs are unstable stars, particularly when they are young – they have a lot of stellar activity and produce charged particles, which can produce intense radiation on nearby planets. Some of this radiation can strip molecules off the top of a planet’s atmosphere and thin it over time.

On March 24, 2017, astronomers discovered that a giant stellar flare erupted from Proxima Centauri. The huge flare was 10 times larger than a major solar flare. And it blasted Proxima Centauri b (also called Proxima b), the exoplanet orbiting within the habitable zone of Proxima Centauri, with 4,000 times more radiation than Earth gets from solar flares. The event probably wiped out the exoplanet’s atmosphere (if exists any), and dimmed the last hopes of extraterrestrial life on it.

Sources:
Alpha Centauri on Wikipedia
Alpha Centauri: Nearest Star System to the Sun on Space.com

Watch: what other stars would look like in the place of the Sun

The Sun is the primary source of energy for Earth’s climate system, and the life on Earth. With a diameter of about 1.39 million kilometers (864,337 miles, i.e. 109 times that of Earth), and a mass about 1.9885×1030 kg (330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System), it may be the biggest thing in this neighborhood, but it is actually just a medium-sized star among the hundreds of billions of stars in the Milky Way galaxy. In the video published by the CAMENGAT creative astronomy below, you can see some dwarf stars and other giants compared to the Sun at the edge of its sphere: at 150 million kilometers (1 AUNotes 1) with a 50 mm objective. The stars are the Sun, Alpha Centauri A, Sirius, Vega, Pollux, Arcturus, Aldebaran, Rigel, Antares, and Betelgeuse. The scenario: Astronomical Observatory of Paranal, Chile.
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Proxima Centauri b May Have Oceans

Proxima Centauri b, the Earth-like planet orbiting the red dwarf Proxima Centauri may have oceans, scientists say. The planet was discovered in August 2016 and caused excitement because it’s in the habitable zone of its star, and it’s rocky. And it’s in the Alpha Centauri, the closest star system to us!
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Proxima Centauri b: Did We Find Earth’s Cousin?

On august 24, 2016, a group of scientists led by Dr. Guillem Anglada-Escude at the Queen Mary University of London, announced the discovery of a terrestrial exoplanet orbiting the red dwarf Proxima Centauri, the nearest known star to the Sun. Proxima Centauri is a Latin idiom, meaning “nearest (star) of Centaurus(1)“. The new planet is named Proxima Centauri b and it is predicted to be orbiting within the habitable zone!
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