On August 23, 2017, astronomers have unveiled a photo that is the most detailed ever image of a star other than our Sun. The image of the red “supergiant” Antares has been constructed using the European Southern Observatory’s (ESO) Very Large Telescope Interferometer (VLTI) on Cerro Paranal (a mountain in the Atacama Desert of northern Chile).

This photo of Antares is the best ever captured of a star other than our Sun.
This photo of the red supergiant Antares is the best ever captured of a star other than our Sun. Image: Wikipedia
The image shows Antares’ tumultuous surface and reveals unexpected turbulence in its atmosphere, hinting at some mysterious process that is churning away violently inside the stellar mass, according to scientists.

The Very Large Telescope Interferometer (VLTI) consists of the coherent combination of the four VLT Unit Telescopes (8.2 meters in diameter) or the four moveable 1.8-meter Auxiliary Telescopes. It is used to resolve small objects. The VLTI provides milli-arcsec angular resolution at low and intermediate (R=12,000) spectral resolution at near-infrared wavelengths.

Due to its characteristics, the VLTI has become a very attractive means for scientific research on various objects like young pre-main sequence stars and their protoplanetary disks, post-main-sequence mass-losing stars, binary objects and their orbits, solar system asteroids, and extragalactic objects such as active galactic nuclei.

Antares

Located around 620 light-years from the Sun, Antares, also known as Alpha Scorpii is the fifteenth-brightest star in the night sky; the brightest star in the constellation of Scorpius, and is often referred to as “the heart of the scorpion”.

It is a red “supergiant”. Its exact size remains uncertain, but, probably with a radius that is approximately 1 billion 228 million kilometers (883 times that of the Sun), it is one of the largest stars in the Universe, and if placed in the center of the Solar System, its outer surface would lie between the orbits of Mars and Jupiter.

It is dwarfed by even larger red supergiants, such as VY Canis Majoris and UY Scuti, though.

Antares’ mass is calculated to be around 12 times that of the Sun.

Antares is also nearing the end of its life. Once there is no more fuel left to burn, the star will collapse and explode into a supernova, possibly in the next ten thousand years. After the explosion, the Antares supernova could be as bright as the full moon and be visible in the daytime for a few months.

Antares vs Sun size comparison
Antares vs Sun size comparison. If placed in the center of the Solar System, Antares’ outer surface would lie between the orbits of Mars and Jupiter.

Antares’ location in the Earth’s sky

Antares in the Earth's sky
How to find Antares in the sky? In the northern hemisphere, if you look southward in the early evening from late spring to early fall, you’re likely to notice the fishhook pattern of Scorpius (Scorpion), with Antares at its heart.
Antares is the fifteenth-brightest star in the night sky; the brightest star in the constellation of Scorpius, and is often referred to as “the heart of the scorpion”.

Sources

  • Antares on Wikipedia
  • Antares: astronomers capture best-ever image of a star’s surface and atmosphere on The Guardian
  • “See the Best-Ever Imagery of a Star Beyond the Sun” on Space.com
  • Very Large Telescope on Wikipedia
  • The Very Large Telescope Interferometer on the European Southern Observatory website
M. Özgür Nevres

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