Antares – the heart of Scorpio

This star has a twin – on the other side of the sky

Video version articles at the end

On short summer nights, one of the most mystical (in our perception) zodiac constellations, the constellation of Scorpio, stealthily rises above the horizon of northern latitudes. It is led by the orange Antares, a star with a strange name. This name is based on the name of the planet, and to be more precise, the name of the Greek god of war – Ares, who among the Greeks has always been associated with the blood-red planet Mars. And only the Romans then imposed on the world the name of the planet – Mars – also by the name of their god of War.

In the middle northern latitudes, Scorpio does not fully rise. At the latitude of Moscow (and most other Russian cities), only the very top appears – “Claws of the Scorpion”. And an extended tail with a poisonous sting (it contains a pair of Cat’s Eyes stars) can only be seen in the subtropics and to the south.

Fortunately, Antares is not far from the pincers. And although now we call it exactly – “Anti-Mars” – if we translate the name literally, since this name arose as a result of chronic confusion – the star was often mistaken for the red planet and vice versa, because every 2 years Mars enters the constellation Scorpio – but in ancient times Alpha Scorpio had several names at once, in no way connected with the planets. The Arabs, who gave astronomy most of the star names, called him Qalb al-Akrab (“Heart of the Scorpion”). The Persians called the star Satevis. In India – Jyestha.

(Movement of the planet Mars in the constellation Scorpio in the period from 02/20/2048 to 09/24/2048)

It’s funny that in the Middle Ages, the Italians called Antares “Evening Star” – Vespertelinowhich introduced another confusion with the planet, but in this case already with Venus.

The best time to observe Antares is the second half of spring and all summer. In autumn, Antares is lost in the evening twilight and again becomes inaccessible to observations until mid-spring. Antares has an antipode star – the red-orange Betelgeuse – the alpha of the constellation Orion. According to Greek mythology, Orion was stung by a Scorpion and died from this poisonous bite. But Zeus saved the soul of the greatest hunter by placing it in the sky in the form of the brightest constellation. And so that Orion and Scorpio no longer meet, Scorpio ended up in the opposite part of the celestial globe, and as soon as Orion rises, Scorpio immediately hides behind the horizon. It is impossible to see these two constellations at the same time in the northern latitudes. And the main stars of these constellations – Antares and Betelgeuse – never shine in the sky at the same time.

But these stars are similar.

Red supergiants 600 light-years away from the Sun, having irregular or semi-regular variability, being at the final stage of evolution, so huge in size that any of these stars (having been in the place of the Sun) would have swallowed up all the planets with their red-hot bowels, including the same Mars (to no longer get in the way). Using the VLT – the “Very Large Telescope” (located in Chile’s Atacama Desert) – astronomers were able to build the first surface maps for both Antares and Betelgeuse almost simultaneously.

For the past couple of years, the entire world community of amateur astronomers has been expecting an explosion of Betelgeuse. This hasn’t happened yet. And now no one knows who will explode first – Betelgeuse or Antares?

However, Antares has a satellite – this distinguishes it from Betelgeuse. At least something was found, otherwise these stars could be considered twin stars.

Antares B has a distinct blue-green hue and is not an easy object to observe. The distance between the stars is a little less than 3 arcseconds, and the bright Antares A most often absorbs the slightly weaker Antares B with its radiance.

The brightness of the stars is +1m and +5.5m.

It is argued that Antares can be divided into components A and B in an amateur telescope only when the star is covered by the Moon – this happens sometimes. The moon alternately covers one component, then the other, and then the stars also alternately appear from behind the lunar disk – with a difference of several seconds. This is how Antares B was discovered in 1819. But for 200 years, amateur telescopes have grown significantly in size and quality. And personally, I remember well that I saw Antares B without any coatings in the Mizar telescope (mirror diameter 110 millimeters) without much difficulty.

Antares B – only seems to be a weak companion of the orange-red giant. By itself, it is also a giant star – 7 times more massive than the Sun, very hot (18 thousand degrees – surface temperature) and with a total luminosity exceeding the solar almost 3000 times.

In the spectrum of Antares B, there are quite a few lines of heavy chemical elements, apparently captured from Antares A, although the stars are not so close in our understanding – they are separated by a distance of 500 astronomical units or 80 billion kilometers – this can be compared with the distance between the Sun and a distant cold Sednoi is the most distant known dwarf planet like Pluto. Nevertheless, the stellar wind of Antares A constantly “blows” over Antares B, enriching its atmosphere with those chemical elements that could not have formed there naturally.

A pair of these stars revolves around a common center of mass in more than a thousand years. For binary stars, this is a very short period of revolution.

On the star map, Antares is located in an area extremely rich in interesting astronomical objects. The Milky Way passing here is the widest and brightest – this is not surprising, because it is in this direction that the center of our Galaxy is located, hidden by dark dust clouds and nebulae.

Antares – being a very bright luminary (its luminosity exceeds the solar one by 60,000 times), it illuminates a vast nebula in which active star formation is taking place. A few more nebulae – illuminated by other, more distant stars – can be found in the same region of the sky. Sometimes it seems that the nebulae practically merge with each other. This is an illusion – they are all at very different distances from us, and only their projections on the celestial sphere are superimposed on each other. Nevertheless, this collection of nebulae is called the Antares Nebula Complex, or even – quite simply – Nebula Antares.

At the end of this short review, I leave you a video in which Antares and its celestial environment can be seen in all its glory.

Sounds like a fragment of my music album “Antares Nebula“. You can listen to the full album at special page.

Video version of the article

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