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I cannot for the life of me remember when it was or what it was but a fair few years ago I remember positioning a telescope to observe an asteroid as it silently and perhaps slightly eerily drifted between us and the Moon. I say eerily as this asteroid had the ability to cause widespread damage had it hit but of course we knew it posed no threat.  I remember at the time thinking it was mind blowing that even today, we still use mathematics with roots (pardon the pun) centuries old to calculate the position of objects in our Solar System. We get to see evidence of this again on 12th December when something rare happens!

I have rather hinted to what I am referring, on 12th December, asteroid 319 Leona will pass directly in front of Betelgeuse, the red giant in the constellation of Orion whose name amusingly translates to armpit of the giant – now there’s a fact to amuse and astound your friends. To be able to calculate that a rock approximately 60 km across is going to pass directly in front of a star that is just over 650 light years away is really quite staggering.

Perhaps more excitingly if you live along a corridor from central Asia and southern Europe to Florida and Mexico then at around 01:17 UTC you have a chance – clouds permitting – to see it for yourself and you don’t need any telescope or equipment, just your eyes.

Betelgeuse is the second brightest star in the constellation Orion and is a familiar favourite with its piercing red colour. It hit the news back in 2020 when it unexpectedly dimmed in the sky due to the star itself ejecting a cloud of dust. Next month it will fade for a few seconds due to the passage of Leona right in front of it. An event like this is quite rare where the light from a bright star is blocked (or occulted) by an asteroid happening every few decades at most.  It will be fascinating to watch but is also scientifically useful giving us a chance to learn more about Betelgeuse and how it’s large convection cells behave, and to learn more about the orbit and shape of the asteroid too. 

Image of Orion showing Betelgeuse upper left.
The Constellation of Orion showing Betelgeuse at upper left (Credit : Till Credner)

Anyone out there wishing to observe the event needs to be warned though, the predictions are just that, there are a few uncertainties. The size and shape of the asteroid itself is still subject to debate. Typically we tend to assume asteroids are spherical unless we know otherwise but a previous occultation of Leona in September 2023 determined that it was more of ellipsoidal in shape measuring 80km by 55km. At its distance from Earth that means it will cover an area of sky 46 x 41 milliarcseconds which is a little more than the approximate 40 milliarcseconds for Betelgeuse. Taking this into account suggests Betelgeuse will be completely blocked from view and therefore blink out for a few seconds.

Betelgeuse’s somewhat diffuse outer atmosphere may mean its apparent size is more like 50 milliarcseconds so it just fades instead.   Until the event happens we will not know exactly how it will appear in the sky or exactly when.   It’s a great opportunity to learn more about these two fascinating objets so head outside on 12th December around 01:00 UTC, wait and watch and hopefully you can witness one of natures rather more rare events. 

Source : OW Cloud Data

The post An Asteroid Will Occult Betelgeuse on December 12th appeared first on Universe Today.

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https://mansbrand.com/hubble-succeeds-where-tess-couldnt-it-measured-the-nearest-transiting-earth-sized-planet/

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15 Years of Data Reveal the Events Leading Up to Betelgeuse’s “Great Dimming”

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Anyone who regularly watches the skies may well be familiar with the constellation Orion the hunter. It is one of the few constellations that actually looks like the thing it is supposed to look like rather than some abstract resemblance. One prominent star is Betelgeuse and back in 2020 it dimmed to a level lower than ever before in recorded history. A team of astronomers have been studying the event with some fascinating results.

Betelgeuse is a red supergiant star almost 650 light years from Earth. With a radius of 617 million kilometres, if it were in the position of the Sun, then the orbit of Earth would be buried deep within its layers. It’s also a variable star which means it varies its output of light and in the case of Betelgeuse this variability is semi-regular or in other words, regular with a few irregularities along the way! Its variability is related to a pulsating of the stars radius which occurs over a period of around 400 days although there is a longer period of variability of around 2,100 days of uncertain origin, possibly linked to variation in convective flow. 

Back in 2020 Betelgeuse dimmed to a level that had never been recorded in what has since been dubbed the “Great Dimming”. It’s visual brightness or magnitude, dropped by 1.6 although its dimming did not seem consistent across the star’s sphere; the southern hemisphere was much darker than the northern and there have been many theories put forward to explain the event. Among them, large formations of star spots or dust clouds above the photosphere are favourite.

A paper published recently in Astronomy and Astrophysics by a team of astronomers led by Daniel Jadlovský explores the Great Dimming event using 15 years of data from the STELLA robotic telescope. The STELLA system comprises two robotic telescopes in Spain coupled with a high resolution spectrograph and a wide field imager. 

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STELLA Observatory in Tenerife, Spain.

The data allowed the team to explore the photosphere (visible layer) of Betelgeuse in incredible detail. They were able to gain valuable insight into the radial pulsations, shockwaves and how they passed through the photospheric layers. Five distinct layers of the photosphere were identified using the tomogrpahic technique – a method where images are constructed form a series of projections.

Analysis revealed that the variations in the innermost photospheric layer, known as C1 was in line with the timescales of the visual magnitude variations. Shockwaves travelling through the layers also seemed to be broadly in line with the brightness variations.  In regards to the Great Dimming vent of 2020, the data showed two powerful shock waves in the photosphere, the first likely to be the cause of a major outflowing of material which caused an infall of all layers. As the infall reached maximum velocity the second, more powerful shockwave occurred leading to the a significant outflow of material. Due to the different photospheric layers, these events didn’t happen simultaneously across them all and it wasn’t until early 2022 that Betelgeuse settled back down. 

Source : The Great Dimming of Betelgeuse: the photosphere as revealed by tomography during the past 15 years

The post 15 Years of Data Reveal the Events Leading Up to Betelgeuse’s “Great Dimming” appeared first on Universe Today.

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Iran Sent a Capsule Capable of Holding Animals into Orbit.

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Despite popular opinion, the first animals in space were not dogs or chimps, they were fruit flies launched by the United States in February 1947. The Soviet Union launched Laika, the first dog into space in November 1957 and now, it seems Iran is getting in on the act. A 500kg capsule known as the “indigenous bio-capsule” with life support capability was recently launched atop the Iranian “Salman” rocket. It has been reported by some agencies that there were animals on board but no official statement has been released.

The Iranian Space Agency (ISA) are gearing up to getting humans into space before 2029 but is testing its launch capability with animal passengers. The capsule was launched on December 6 2023 and attained an orbital altitude of 130 kilometres. According to their Telecommunications Minister Isa Zarepour, it is aimed at sending Iranian astronauts to space by 2029.

The “Salaman” solid-fuelled rocket was designed by the aerospace division of the Ministry of Science, Research and Technology and built and launched by the Ministry of Defence and Armed Forces Logistics. It has already been used to launch a data collecting satellite and in 2013 successfully sent and returned monkeys into space.

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Ham, a chimpanzee, became the first great ape in space during his January 31, 1961, suborbital flight aboard Mercury-Redstone 2 (Credit : NASA)

To date, only three counties have human spaceflight capability; USA, Russia and China. India are attempting to become the fourth as they work on their Gaganyaan program. Will Iran become the fifth!? Iran plans further tests with further launches bearing animal occupants before attempting to send humans up.

According to the Iranian Space Agency, its satellite program is purely for scientific research and other civilian applications. There is however, international suspicion because there are suspicions that the Salamn rockets could very easily be converted to long range missiles.

Source : Iran says it sent a capsule capable of carrying animals into orbit as it prepares for human missions

The post Iran Sent a Capsule Capable of Holding Animals into Orbit. appeared first on Universe Today.

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https://mansbrand.com/what-could-a-next-generation-event-horizon-telescope-do/

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What Could a Next Generation Event Horizon Telescope Do?

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Telescopes have come a long way in a little over four hundred years! It was 1608 that Dutch spectacle maker Hans Lippershey who was said to be working with a case of myopia and, in working with lenses discovered the magnifying powers if arranged in certain configurations. Now, centuries on and we have many different telescope designs and even telescopes in orbit but none are more incredible than the Event Horizon Telescope (EHT). Images las year revealed the supermassive black hole at the centre of our Galaxy and around M87 but now a team of astronomers have explored the potential of an even more powerful system the Next Generation EHT (ngEHT).

There is no doubt that our understanding of the processes within our Universe have come on leaps and bounds since the invention of the telescope. The resolution of these space piercing instruments is dictated by the telescope’s aperture. The technique known as interferometry hooks individual telescopes together and combines their signal so they act as one BIG telescope, boosting the resolution. 

Telescopes like the EHT have been using interferometry to great advantage to study black holes. These enigmatic and mysterious stellar corpses defy our probing; we do not fully understand their origins and processes and indeed our laws of physics break down if you get too close to the point source in the centre, the singularity. Due to their interaction with space and time, understanding the full nature of black holes will – hopefully – unlock our understanding of the Universe. 

Previously, observations have only revealed the movement of stars around galactic centre suggesting an object was lurking there weighing in at around 4 million times the mass of the Sun. Data from the EHT collected during 2022, finally revealed an image of the object at the centre – SgrA* – a super massive black hole and the matter in the immediate vicinity of the event horizon. Whilst this image did not reveal the black hole itself – another article required to explain that – it certainly revealed the telltale signs. 

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Sag A* compared to M87* and the orbit of Mercury. Credit: EHT collaboration

A recently published paper explores the possibilities of the ngEHT and how they might be able to unpick some of the physics around black holes. The ngEHT will increase the geographical footprint of EHT by 10 further instruments that span across the Earth.  Making use of the significant improvement in resolution, the ngEHT will also improve image dynamics range, provide a multi-wavelength capability and facilitate long term monitoring. 

The team conclude that future enhancements in measurement sensitivity and data analysis techniques in ngEHT will substantially advance our understanding of black holes and the immediate environments surrounding them with particular focus on the photon ring, mass and spin analysis, binary supermassive black holes and more besides.

Source : Fundamental Physics Opportunities with the Next-Generation Event Horizon Telescope

The post What Could a Next Generation Event Horizon Telescope Do? appeared first on Universe Today.

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