In the show this time, we talk to Richard Bower about simulating the Universe with the EAGLE project, Shruti Badole rounds up the latest news, and we find out what we can see in the November night sky from Ian Morison and Haritina Mogosanu.
This month in the news: the slowest-spinning pulsar ever discovered, elusive dust clouds around the Earth finally detected and the Hubble Space Telescope returns.
First up in the news: An international team of astronomers led by Chia Min Tan, a doctoral student at our very own Jodrell Bank Centre for Astrophysics, has discovered the slowest-spinning pulsar ever. The team also comprised of astronomers at the Netherlands Institute for Radio Astronomy, also known as ASTRON and the University of Amsterdam.
Pulsars are rapidly spinning neutron stars, which are basically the collapsed cores of massive stars that have undergone supernova explosion. They are extremely dense and are also highly magnetised, as a result of which, the spinning of the neutron star leads to generation of electromagnetic radiation. This radiation manifests itself in the form of beams emanating from the magnetic poles of the pulsars. Similar to a lighthouse, the beams from a pulsar flash consistently and can only be observed if the radio emission from the beam is facing the Earth. While the fastest spinning pulsar ever discovered rotates once every 1.4 milliseconds, meaning 716 times per second, the slowest pulsar known until this discovery rotates every 8.5 seconds. This record has now been broken by the recently discovered radio pulsar PSR J0250+5854, whose rotation period has been found to be 23.5 seconds. The pulsar is approximately 14 million years old and is located in the constellation Cassiopeia, around 5,200 light years away from the Earth. It was discovered as part of the LOFAR Tied-Array All-Sky Survey that is searching for pulsars in the Northern sky.
Generally, pulsars are said to have reached their "death line" after about 10 to 100 million years, when the magnetic mechanism responsible for the pulsar jets shuts down. The newly discovered pulsar is considered to be very unusual because it goes beyond the conventional pulsar death line, where the radio emission is expected to cease. A co-author of the study, Dr Jason Hessels from ASTRON and the University of Amsterdam, says: "This discovery was completely unexpected. We're still a bit shocked that a pulsar can spin so slowly and still create radio pulses. Apparently radio pulsars can be slower than we expected. This challenges and informs our theories for how pulsars shine."
The team plans to further study the pulsar with the European Space Agency's XMM-Newton space telescope. Chia Min Tan says, "This telescope is designed to detect X-rays. If the super-slow pulsar is detected as a source of X-rays, then this will give important insights into its history and origin". Meanwhile, the team is looking forward to discovering more pulsars with the LOFAR survey. The study can be found in the Astrophysical Journal.
In other news: A team of astronomers from Hungary have confirmed the existence of two clouds of dust at gravitationally semi-stable points about 400,000 kilometers from the Earth. The possibility of the existence of these clouds, known as Kordylewski dust clouds (or KDCs), was first discussed by the Polish astronomer Kordylewski in 1961. However, due to their extreme faintness, KDCs remained elusive objects and their existence was doubted by a lot of astronomers all these years. In the new study, the team of astronomers modeled KDCs to understand their formation and detection. The results obtained are consistent with the earliest observations of KDCs made over six decades ago and also match with predictions made by an earlier research by the team. Team member Dr. Judit Sliz-Balogh of the Eotvos Lorand University commented on the discovery, saying: "KDCs are two of the toughest objects to find, and though they are as close to Earth as the Moon are largely overlooked by researchers in astronomy. It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbor". Two research papers related to the study can be found in the Monthly Notices of the Royal Astronomical Society.
And finally: The Hubble Space Telescope is back in action! The HST, that has 6 gyroscopes that help maintain its orientation during observations, faced a glitch early October after failure of one of the gyroscopes. There was further trouble with the backup gyroscope as well, which was spotted after the rotation rates it measured were found to be higher than the actual ones. This sent the HST into a protective safe mode, putting all science observations on hold. Thankfully, after a series of engineering tests undertaken by the Hubble operating team, the telescope has now returned to normal science operations.
Interview with Richard Bower
Professor Richard Bower (University of Durham) talks to us about theoretical and observational aspects of studying galaxies and galaxy clusters. As part of the EAGLE project he has simulated the Universe, and tells us how they went about such a monumental task plus what they've learnt from it. He also updates us on the Ordered Universe project, a conjunction of science, history, and language in the study of Medieval scientific literature.
The Night Sky
Ian Morison tells us what we can see in the Northern Hemisphere night sky during November 2018.
- Jupiter - Jupiter is now moving towards its superior conjunction behind the Sun on November 26th and will not be visible this month.
- Saturn - Saturn will be visible in the southwest at an elevation of ~11 degrees after sunset at the beginning of November but disappears into the Sun's glare by the end of the month. Its disk has an angular size of 15.7 arc seconds falling to 15.2 during the month whilst its brightness increases slightly from +0.5 to +0.6 magnitudes as the month progresses. The rings were at their widest last year but are still, at 24 degrees to the line of sight, well open and spanning ~2.5 times the size of Saturn's globe. Saturn is now moving westwards over the 'teapot' of Sagittarius to the left of M8, the Lagoon Nebula, and M20, the Trifid Nebula. Sadly, atmospheric dispersion will greatly hinder our view.
- Mercury - Mercury reaches its greatest elongation east from the Sun on November 6th but, as the angle of the ecliptic to the horizon in the evening is shallow at this time of the year, it will be lost in the Sun's glare as it moves towards inferior conjunction (between us and the Sun) on the 27th of the month.
- Mars.Though fading from magnitude -0.6 to -0.1, Mars actually becomes more prominent in the southern sky after sunset as it climbs higher in elevation from ~17 degrees at the start of the month to ~27 degrees by month's end. Its angular size is 11.9 arc seconds at the start of the month falling to 9.3 arc seconds by its end. Moving from Capricornus into Aquarius on November 11th, it should still just be possible with a small to medium sized telescope to spot details, such as Syrtis Major, on its salmon-pink surface.
- Venus - Venus passed between us and the Sun (inferior conjunction) on October 26th and can be seen from around the 8th of this month in the east before sunrise. As, at this time of the year, the ecliptic at dawn has a steep angle to the horizon it rapidly increases in elevation as November progresses and will have an elevation of ~20 degrees before sunrise by month's end. The planet brightens from -4.6 to a dazzling -4.9 magnitudes during November making it dominate the pre-dawn eastern sky. Its angular size reduces from 60.6 to 41.4 arc seconds during the month as it moves away from the Earth but at the same time the percentage illuminated disk (its phase) increases from 1% to 25% - which is why the brightness actually increases.
- November - still a good month to observe Neptune and Uranus with a small telescope. Neptune came into opposition - when it is nearest the Earth - on the 7th of September, so will still be well placed to spot this month. Its magnitude is +7.9 so Neptune, with a disk just 2.3 arc seconds across, is easily spotted in binoculars lying in the constellation Aquarius as shown on the charts. It rises to an elevation of ~27 degrees when due south. Given a telescope of 8 inches or greater aperture and a dark (around the 7th) transparent night it should even be possible to spot its moon Triton.
- Around the 7th of November (with no Moon in the sky): find M31 - The Andromeda Galaxy - and perhaps M33 in Triangulum. In the evening, the galaxy M31 in Andromeda is visible in the south. The chart provides two ways of finding it:
- November early mornings: November Meteors. In the hours before dawn, November gives us a chance to observe meteors from two showers. The first that it is thought might produce some bright events is the Northern Taurids shower which has a broad peak of around 10 days but normally gives relatively few meteors per hour. The peak is around the 10th of November, just after new Moon, so its light will not intrude. The meteors arise from comet 2P/Encke. Its tail is especially rich in large particles and, this year, we may pass through a relatively rich band so it is possible that a number of fireballs might be observed!
- November - evening: find the 'Coathanger'. Looking upwards after dark high in the south-west you should spot the three stars making up the 'Summer Triangle'. The lowest is Altair in Aquilla, up to its right is Vega in Lyra and over to its left is Deneb in Cygnus. With binoculars sweep upwards about one third of the way from Altair towards Vega. You should spot a nice asterism, formally 'Brocchi's Cluster' but usually called the Coathanger. It is formed of a straight line of six stars below which is a 'hook' of four stars. A pretty object!
- November - late evening: Find the asteroid Juno in Eridanus. Asteroid 3, Juno, makes its closest approach to Earth on November 16th/17th moving southwards in the constellation Eridanus as shown on the chart. On the first of November, looking southeast at ~11 pm it will have an elevation of 27 degrees and a magnitude of 7.58 and lie just above the 5.2 magnitude star 35 Eridani - so helping one to find it with binoculars. On the 17th, with a magnitude of 7.46, it will lie just down to the right of the 4.7th magnitude star 32 Eridani - so, again, helping one to find it with binoculars. Continuing its southwards motion, it will lie just above 22 Eridani (magnitude 5.5) on the last day of the month having a magnitude again of 7.58.
- November 4th - 1 hour after sunset: Mars close to Delta Capricornus. Looking South Southeast after sunset one should, if clear, be able to spot Mars less than 1 degree up and to the right of the 3rd magnitude eclipsing binary star system Deneb Algedi (Delta Capricornus - 49 Capricornus).
- November 11th - after sunset: Saturn below a thin crescent Moon. Given a low horizon towards the Southwest, and if clear, a very nice photo opportunity will arise with Saturn lying just a little to the lower right of a thin crescent Moon, four days after new.
- November 16th - after sunset: Mars close to the Moon. After sunset on the 16th, Mars will be seen over to the right of the Moon, just after first quarter.
- November 17th - before dawn: Venus and Spica. If clear, and given a low eastern horizon, Venus (magnitude -4.56) will be seen just one and a half degrees to the lower left of Spica (magnitude 0.95) in Virgo.
- Hyginus Crater and Rille. For some time a debate raged as to whether the craters on the Moon were caused by impacts or volcanic activity. We now know that virtually all were caused by impact, but it is thought that the Hyginus crater that lies at the centre of the Hyginus Rille may well be volcanic in origin. It is an 11 km wide rimless pit - in contrast to impact craters which have raised rims - and its close association with the rille of the same name associates it with internal lunar events. It can quite easily be seen to be surrounded by dark material. It is thought that an explosive release of dust and gas created a vacant space below so that the overlying surface collapsed into it so forming the crater.
2) You can also find M31 by following the 'arrow' made by the three rightmost bright stars of Cassiopeia down to the lower right as shown on the chart.
Around new Moon (7th November) - and away from towns and cities - you may also be able to spot M33, the third largest galaxy after M31 and our own galaxy in our Local Group of galaxies. It is a face on spiral and its surface brightness is pretty low so a dark, transparent sky will be needed to spot it using binoculars (8x40 or, preferably, 10x50). Follow the two stars back from M31 and continue in the same direction sweeping slowly as you go. It looks like a piece of tissue paper stuck on the sky just a bit brighter than the sky background. Good Hunting!
Haritina Mogosanu from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during November 2018.
- Introduction. My name is Haritina Mogosanu and I am your starryteller from Space Place at Carter Observatory in Wellington New Zealand. November is my favourite month of the year. The name November comes from Latin, meaning the ninth. In ancient times, it was the ninth month from the beginning of the year, in March.
- Stars and Constellations. Looking towards the southern horizon you should be able to see these asterisms on:
- Eastern Sky. Back to the Eastern Sky, this time of the year, the Pleiades are visible again on the horizon. Harbingers for Halloween in the northern hemisphere where now skies are grey and ravens await for the first snows, for Maori, the Pleiades are now harbingers of summer. Together with the Hyades they make the wake and feathers from the Great Canoe (Waka) of Tama Rereti.
- Magellanic Clouds. With the Milky Way laying across the horizon, there aren't so many deep sky objects handy to observe. However, we are in the Southern Hemisphere and the spectacular Magellanic Clouds (or Nubeculae Magellani) are high in the sky at this time of the year. Remember they were the sail of the waka o Tama Rereti and this sail is now set. In my first night here in New Zealand, I printed a map of them and started looking onto the southern sky annoyed by a cirrus cloud I thought, only to discover to my delight that it was the Large Magellanic Cloud I was looking at. It is that spectacular and substantial. The large Magellanic Cloud is about 160,000 light years from us and the Small Magellanic Cloud is about 200,000 light years away. To find them, draw a line from the Southern Cross to Achernar. Two thirds from the Southern Cross on each side of the line are the two galaxies. Now far apart, it seems that they collided in a the past, as a paper just published in October 2018 in the Astrophysical Journal Letters supports that idea with data from the Gaia satellite.
- Pegasus. To the North, the great horse of Pegasus is flying through the sky. Andromeda is in the sky too and if we could only see it from Wellington... but even if we did it would be like a smidgen, since is very close to the horizon.
- On the planetary realm. At the beginning of the month Jupiter and Mercury will be low in the west at dusk, setting toward the southwest 1.5 hours after the sun. Orange Mars is in Capricornus north of overhead at dusk. Midway between Mars and Jupiter is Saturn in Sagittarius. Jupiter sets earlier each night as we move to the far side of the sun from it. By mid-month it is lost in the twilight. Mercury holds its position in the west before disappearing late in November when it passes between us and the sun. A thin crescent moon will be near Mercury and Jupiter on the 9th. At the end of the month Saturn and Mars are the only naked-eye planets in the evening sky. The moon will be near Saturn on the 11th and 12th and close to Mars on the 16th. Venus rises a little south of east 50 minutes before the sun at the beginning of the month; more than 1.5 hours before sunrise at the end. It is a long thin crescent in a telescope and big binoculars.
- Phases of the Moon. The month starts with the Moon at Last Quarter, then New Moon is on the 8th, followed by First Quarter on 16 November and full Moon on the 23rd.
- And with this, I wish you a great November, good night and clear skies from Space Place at Carter Observatory in Wellington New Zealand.
November 15 at 9:30 PM NZDT
December 1st at 8:30 PM NZDT
Three Royal Stars hang across the evening sky of November: Aldebaran in Taurus, Fomalhaut in Piscis Austrinus and Antares in Scorpius. According to French astronomer Camille Flammarion, the royal stars were the ancient guardians of the sky in ancient Persia. It is believed that the sky was divided into four districts each guarded by one of the four Royal Stars.
My favourite of them has always been Fomalhaut (Haftorang/Hastorang) the Watcher of the South. Back in the Northern Hemisphere, Fomalhaut was the southernmost significant star that I could see and we would always look at it as the secret pointer to the South. The rumours were not far off as Fomalhaut, Achernar and Canopus are almost in a straight line and if you can find Achernar you can always find the South easily.
The home-constellation of Fomalhaut is Piscis Austrinus, south of Capricornus and Aquarius, which is maybe why one of its names was Piscis Capricorni (Goat's horn fish). Another name is Piscis Solitarius - the lonely fish. Though here in New Zealand we do have The Chocolate Fish that also comes wrapped individually, I wish we could just rename the constellation to that, for obvious reasons. And just saying, if you never had chocolate fish from New Zealand you never lived!
The lonely fish drinks all the water from Aquarius's stream, says Richard Allen quoting the poets Virgilius and Ovidius who wrote that in their verses a few thousand years ago. Allen also mentions a translation inscribed in a 1340 manuscript almanac naming the constellation 'Os Piscis Meridiani', where meridional means southern of course, so just another synonym of Austrinus. According to Ian Ridpath, Eratosthenes called this the Great Fish and said that it was the parent of the two smaller fish of the zodiacal constellation Pisces (also known as "The Fish").
Today, Fomalhaut is the eye of the southern (chocolate) fish although, adding to the confusion, its original Arabic name "Fum al Hut" was translated as the mouth of the fish. However, just to clarify things, it seems that the Arabs' called it "the first frog" which last time I checked was not a fish.
Because it's the brightest star in a part of the sky that contains mostly faint stars it was used in navigation just like Achernar. A triple system, Fomalhaut is about 25 light-years from Earth and In 2008, it became the first star with an extrasolar planet candidate (Fomalhaut b) imaged at visible wavelengths.
Scorpius is Tauihu, the prow, floating low on the western horizon. Due south sits Te Punga, the anchor (the Southern Cross), with its rope, Te Taura, which is represented by the Pointers (Beta and Alpha Centauri). The latter is actually a multiple star system that holds our closest solar neighbour, the red dwarf Proxima Centauri, at 4.25 light years from Earth.
The sails of Tama Rereti's canoe are Achernar and the beautiful southern dwarf galaxies the Small and Large Magellanic Clouds (SMC and LMC). Canopus/Atutahi is the paramount chief of the skies at vigil in the waka. A source of X-rays and the most luminous close star at 310 light years from the Sun, Canopus is used for navigation by all spacecraft that employ star tracker devices, which determine the orientation (or attitude) of the spacecraft with respect to that star. Te Taurapa, or the stern of the waka is in the Eastern Sky, formed by Orion.
Here in New Zealand we can see both Scorpius and Orion in the sky in the same time and this is the time of the year to do it.
The Large Magellanic Cloud is home of Tarantula Nebula that gets its name from its resemblance to a huge spider. Tarantula Nebula is very luminous, so great that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast visible shadows. In fact it is the most active starburst region known in the Local Group of galaxies.
The Small Magellanic Cloud is on the other side of the imaginary line that goes from Achernar to the Southern cross. Recent research suggest a giant piece broke off the Small Magellanic Cloud in South-Eastern part of the galaxy, which goes toward the Large Magellanic Cloud at a speed of 64 kilometers per second and that the Small Magellanic Cloud may in fact be split in two, with a smaller section of this galaxy being behind the main part of the SMC (as seen from Earth's perspective), and separated by about 30,000 light years. The reason for this might be due to a past interaction with the LMC splitting the SMC, and it is believed now that the two sections are still moving apart. The smaller remnant of the Small Magellanic Cloud is now called the Mini Magellanic Cloud, a MiniMe of a galaxy.
About 15 times closer than the Small Magellanic Cloud but on the same line of sight is my favourite star cluster 47 Tucanae, the most beautiful globular cluster, rival of Omega Centauri.
Odds and Ends
Recently published ALMA observations of Europa at millimetre wavelengths include maps of Europa that show details as small as 200 km. While this is a technically impressive imaging achievement, the results can also be used to understand the composition of the surface of Europa as well as the thermal characteristics of the moon. Pictures and more information are available from the press release.
The Opportunity Rover on Mars, which has been sending data back to Earth for fourteen years, has fallen silent since 10th June 2018, when a severe dust storm made it unable to use its solar panels to generate power. On 11th September, NASA announced that they would undergo a 45-day "active listening" period, where they'd both attempt to send commands to Opportunity and listen for any signals arriving from it. The initial 45-day deadline has now passed, but NASA has decided to extend their attempts to contact Opportunity until January 2019, as over the next few months the area Opportunity was in will see strong winds. It's hoped that if Opportunity's silence is because its solar panels are covered in dust, these winds might clear it off and allow us to communicate again. If you're interested in updates on this, Twitter hashtags #WakeUpOppy and #SaveOppy will let you follow any news.
Are you feeling lucky? The authors of a new study on O-type stars are, having extended the technique of lucky imaging to work with a spectrograph, pioneering "lucky spectroscopy". Taking many spectra with very short exposure times, the effects of atmospheric turbulence are mitigated, which has allowed the blended components of five O-star systems to be resolved, some for the first time.
|Interview:||Richard Bower and Emma Alexander|
|Night sky:||Ian Morison and Haritina Mogosanu|
|Presenters:||George Bendo, Fiona Porter and Jake Staberg Morgan|
|Editors:||George Bendo, Beth Jones, Tom Scragg, Hongming Tang and Bin Yu|
|Segment Voice:||Tess Jaffe|
|Website:||Jake Staberg Morgan and Stuart Lowe|
|Producer:||Jake Staberg Morgan|
|Cover art:||A new ALMA image of the Galilean moon Europa. CREDIT: ALMA (ESO/NAOJ/NRAO), S. Trumbo et al|