Now You See It... In the show this time, we talk to Alexandre Lazarian about magnetic fields in astronomy, Michael Wright rounds up the latest news, and we find out what we can see in the January night sky from Ian Morison, Haritina Mogosanu and Samuel Leske.
This month in the news: the launch and testing of the CHEOPS mission and a possibly volcanically active Venus.
First up, in late December the CHEOPS mission launched. This stands for CHaracterising ExOPlanets Satellite, and as the name suggests, is a mission aimed at determining better the properties of exoplanets.
The main goal of the mission will be to look for transiting exoplanets already discovered and make accurate measurements of their size. Combine that with good estimates for their mass, which we have from the transiting work on them, and follow-ups on radial velocity, and we can get an idea of their average density.
On the 8th of January the telescope electronics were turned on, and everything went as planned. Then the CCD was turned on with a picture taken with the telescope cover closed. As we know this should produce a dark picture. This gives a good indication of whether the imaging systems are working. As of now, the satellite is working well with everything as expected. The internal temperature appears to be stable, the electronics working well.
That was not the only satellite in that launch, though. CHEOPS launched as a secondary payload to a satellite of the Italian space energy, a second generation COSMO SkyMed, and 3 cubesats were also in the same rocket.
COSMO SkyMed is a constellation of 4 satellites used by the Italian Space Agency for radar based observation of Earth. The satellites are coming to the end of their expected life so generation 2 was commissioned around 2015, which will be two satellites (this one and another to be launched some time this year) which aim to replace the old constellation, as well as make some improvements in the quality of image they can record - for example improving the spatial resolution.
One of the cubesats in the launch is also quite an interesting idea to discuss. OPS-SAT is a cubesat designed to be a platform to experiment with mission control for satellites with more powerful computers. The satellite is designed solely around this idea of mission control: if there is a new control system software that ESA wants to test, they can test it using this and not have to weigh up whether it is worth risking a satellite which is doing useful studies of the universe. This should help test more advanced control systems before they are used on larger, more expensive projects.
Also in the news recently, a study about volcanism on Venus.
To set this up, we know in the past Venus had volcanism because of infrared and visible thermal images of lava flows from the Venus Express orbiter. The atmosphere will cause oxidation on the surface, which will have an effect on the emissivity of that surface in the wavelengths we are viewing them. Younger lava flows will be less weathered and will have a higher emissivity, we will see a higher amount of infrared from them in a particular time window.
A recent paper measures the near infrared spectra of olivine, a crystal expected to be produced in the lava flows of Venus as its surface is largely basaltic and olivine is produced on Earth in eruptions like those expected to have happened on Venus. The experiment was done using a furnace to create high temperatures, however it is worth noting that it was done under Earth’s atmosphere, which may mean the results differ from the surface of Venus. This weakness is mentioned in the paper.
However despite this the paper throws up something very interesting. The crystals become coated at that temperature within about a month. To quote the paper: "After 1 month of oxidation at 900°C, the VNIR spectra show no features characteristic of olivine (i.e., the broad 1000-nm absorption), even though the bulk sample remained predominantly olivine". They also measured samples at 600°C which is far closer to the surface temperature of Venus, these samples showed reduced effects of olivine.
Now it may be that the different atmosphere on Venus changes the timescale of this oxidation somewhat, but the finding of a timescale of weeks to months for this effect could suggest that the lava flows on Venus could be very recent. And if those flows are from months or years ago rather than millions of years then Venus has volcanic activity.
The paper finishes by pointing out that this would fit in well with the discovery of spikes in the concentration of sulphur in the atmosphere measured by both the Pioneer Venus Orbiter and the Venus Express satellite. Those spikes in concentration could have been the result of some form of eruption.
Interview with Alexandre Lazarian
We speak to Alexandre Lazarian, a professor in the University of Wisconsin-Madison who has done a wealth of theoretical work in astrophysics. In particular, he is a world authority on magnetic fields, interstellar dust and turbulence. We talk about what magnetic fields are, why they are important and how we can produce a 3D map of the magnetic fields in our Galaxy. We also discuss the synergy between theory, simulations and observations in astrophysics; and the race to detect the elusive primordial "B-modes", complicated by light from our own Galaxy.
The Night Sky
Ian Morison tells us what we can see in the Northern Hemisphere night sky during January 2020.
- Jupiter passed behind the Sun on December 27th, 2019 and will be lost in the Sun's glare in the early part of January. But, by the middle of the month, it will become visible, shining at magnitude -1.9 in the pre-dawn sky and, by month's end, will rise about an hour before the Sun. A low eastern horizon will be needed and our views of the giant planet and its Gallilean moons will be hindered by the depth of atmosphere through which it will be observed.
- Saturn passes directly behind the Sun on the 13th of January so could not be seen until the very end of the month. Then, equipped with binoculars and a very low eastern horizon, it might be glimpsed at magnitude 0.6 in the pre-dawn sky as it rises about 40 minutes before the Sun - but please do not use binoculars after the Sun has risen.
- Mercury passes in front of the Sun (superior conjunction) on the 10th of January so will not be visible until the very end of the month. Then, at magnitude -1.0, it will set about 70 minutes after the Sun and will have an elevation, low in the west southwest, of ~9 degrees. Binoculars may well be needed, but please do not use them until after the Sun has set.
- Mars can be seen towards the southeast in the pre-dawn sky at the start of the month. It then rises some three hours before the Sun and will be best seen at around 7am having an elevation of ~11 degrees. It will have a magnitude of +1.6 and a 4.3 arc second, salmon-pink, disk. By month's end it will be seen further round towards the south before dawn and its magnitude will have increased slightly to +1.4.
- Venus rises rapidly in the twilight sky this month. As January begins, it could be best seen, shining at magnitude -4, at about 5 pm having an elevation of ~11 degrees above the south-western horizon. As the month progresses, remaining at magnitude -4, its elevation at sunset increases and will be best seen at about 6 pm having an elevation of ~22 degrees. During the month its angular size increases from 13 to 15 arc seconds but, at the same time, it phase (the percentage of the disk illuminated) decreases from 82% to 74% and so the brightness remains constant.
- January, evening: the Double Cluster and the 'Demon Star', Algol. January is a good time to look high in the south after dark towards the constellations of Cassiopea and Perseus. Perseus contains two interesting objects; the Double Cluster between the two constellations and Algol the 'Demon Star'. Algol in an eclipsing binary system as seen in the diagram below. Normally the pair has a steady magnitude of 2.2 but every 2.86 days this briefly drops to magnitude 3.4.
- January: find M31 - The Andromeda Galaxy - and perhaps M33 in Triangulum. In the evenings when the Moon is not prominent, the galaxy M31 in Andromeda will be visible high in the south. There are two ways of finding it:
1) Find the square of Pegasus. Start at the top left star of the square - Alpha Andromedae - and move two stars to the left and up a bit. Then turn 90 degrees to the right, move up to one reasonably bright star and continue a similar distance in the same direction. You should easily spot M31 with binoculars and, if there is a dark sky, you can even see it with your unaided eye. The photons that are falling on your retina left Andromeda well over two million years ago!
2) You can also find M31 by following the "arrow" made by the three rightmost bright stars of Cassiopeia down to the lower right.Around new Moon (24th January) - 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!
- January 4th - before dawn: Mars lies above Antares in Scorpius. If clear before dawn on the 4th, one will see Mars (magnitide +1.55) just above the first magnitude red giant star Antares.
- January 7th - evening: the Moon lies within the Hyades Cluster. In the evening one could see the waxing Moon, moving towards full, lying above Aldebaran in the Hyades Cluster. Aldeberan is a red giant star far closer to us than the Hyades.
- January 10th - after sunset: Venus lies above Delta Capricornus. After sunset, low in the southwest, Venus will lie above the ~3rd magnitude star Delta Capricornus or Deneb Algedi.
- January 27th - evening: a very thin crescent Moon lies between Venus and Mercury. If clear after sunset, looking towards the southwest one could see a very thin crescent Moon, just 3 days after New, lying below Venus and above Mercury.
- January 7th and 24th: Two Great Lunar Craters These are two great nights to observe two of the greatest craters on the Moon, Tycho and Copernicus, as the terminator is nearby. Tycho is towards the bottom of Moon in a densely cratered area called the Southern Lunar Highlands. It is a relatively young crater which is about 108 million years old. It is interesting in that it is thought to have been formed by the impact of one of the remnents of an asteroid that gave rise to the asteroid Baptistina. Another asteroid originating from the same breakup may well have caused the Chicxulub crater 65 million years ago. It has a diameter of 85 km and is nearly 5 km deep. At full Moon the rays of material that were ejected when it was formed can be see arcing across the surface. Copernicus is about 800 million years old and lies in the eastern Oceanus Procellarum beyond the end of the Apennine Mountains. It is 93 km wide and nearly 4 km deep and is a classic "terraced" crater. Both can be seen with binoculars.
Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during January 2020.
Welcome to a new decade of astronomy, discovery and fun!
Haritina Mogosanu and Samuel Leske from New Zealand have recorded a live observing session of the New Zealand's night sky.
This month we look up into the night sky of January and February.
We are actually at Stonehenge Aotearoa (New Zealand) in the middle of the night. To the south is the Southern Cross with the famous globular cluster Omega Centauri almost about to peer behind the tree, and then we can follow the Milky Way up past the asterisms of the Diamond Cross, the False Cross, Canis Major, Orion, then we have Taurus, the Pleiaides, or Matariki as we are calling these stars here, Aries, and that's the end of the Milky Way.
This time of the year we can see only one spiral arm of our galaxy, the one we actually live in, the Orion Spur. Everytime we look towards Orion we look toward the edge of the galaxy. Every time we look towards Scorpius (which is now well beyond the horizon) we look towards the centre of our galaxy.
This time of the year is also when we see very bright stars, not as many clusters and objects that are at the centre of the galaxy but still plenty in Carina Vela and Crux region here, all these objects are oldies but goldies and we still have the Magellanic Clouds to admire, they are very beautiful, especially under a dark sky like the one from Wairarapa.
Stonehenge Aotearoa is located in the North Island of New Zealand in Wairarapa, which is one of the darkest locations in New Zealand.
We decided to do something different this month and record live on this location from where we usually do our deep sky stargazing away from the light pollution of the big cities.
With us we have the giant 16 inch telescope and we have been galaxy hunting all evening. The field of galaxies hunting is pretty amazing at the moment. In Grus, there is the Grus quartet, with four really bright galaxies; in Cetus there is Cetus A - we find about 5 galaxies around that one; in Fornax, if you follow the great Eridanus river around the sky, which goes from Orion's Rigel, all the way to Achernar here in New Zealand and is now at zenith, well up there are about 10 galaxies, at one point we had 6 galaxies simultaneously in the eyepiece. In terms of starhopping you will find these half way through between Rigel and Achernar, as you look towards Achernar from Rige, there are 4 stars looking like a parallelogram, to the left of those stars is a tiny little triangle and that's where you see these galaxies.
We also decided to try out our narrow band OIII filter on the telescope and had a great look at Eta Carinae nebula and Tarantula nebula and browsed the Large Magellanic Cloud to see nebula after nebula. The filter makes a great difference to viewing.
We are now going to move the large Leviathan telescope and look at the 47 Tucanae globular cluster, which is one of the greatest globular clusters in the southern hemisphere, here in New Zealand is located on the south circumpolar region; the nucleus of this globular cluster is very well defined. You can resolve the stars to the centre in the core and it almost looks tri dimensional.
Now we look at Sculptor galaxy, which is a famous and easy-to-look-at galaxy here in the southern hemisphere. We can see the galaxy spanning across the entire eyepiece and fits in a very pointy triangle that also spans the length of the eyepiece almost perpendicular to the galaxy. Through the middle of Sculptor are four stars, another parallelogram.
We will now try and find M1, the Crab nebula in Taurus, which also looks great with the OIII filter on. M1 is a wispy cloud remnant from a supernova explosion that occurred in 1054. Taurus is really high, and we can also see the Pleiades, Hyades and Aries on the northern horizon.
In New Zealand, the stars of the zodiacal constellations shift slowly through the northern part of the sky and they move on the sky counter clockwise looking north, completely the other way around like in Europe. We can also see Orion that is upside down in the sky and from it we can observe the galactic arm stretching all the way to the Southern Cross where we can see with the naked eye the Flounder - or the Coalsack as we know it in Europe, the Flounder (Te Patiki) is the Maori name of this region of space where dust obscures the light that comes from the stars. Inside it, is the Jewel Box.
The Magellanic clouds are very bright right now. Canopus is almost at Zenith, and we can make a line from Sirius, the brightest star in the sky to Canopus, the second brightest star in the sky, if you extend that line it will point towards the Large and Small Magellanic Clouds - the four objects are aligned.
Back to the Crab Nebula it looked fluffy and beautiful. Hard to believe this was visible in the daytime for three weeks when the star went supernova in 1054. Close to it, we also observed Orion's nebula, a place where stars are born. In this telescope, M42 is very bright with the four stars of the trapesium being very clearly visible. We are also observing M78 that Sam believes is the forgotten cousin of M42 on which everyone focuses usually, but seeing this beautiful reflection nebula in M78 lit up by the brightest stars, you realise it's a great object on its own, and you can notice a dust line that stands out quite well.
Next we look at Eta Carinae, just because it's so beautiful. We always visit this one. The dust lines are spectacular and there is a really crisp boundary between the nebula and the lines of dust. With the OIII filter, the nebula is very sharp. Close to it, the Wishing Well cluster (NGC 3532) is a massive collection of stars that fills the eyepiece, with almost equidistant stars, one of them is really bright, the cluster is almost resembling a snowflake. On the other side of the Carina Nebula, sitting almost straight on the Galactic Equator is Gem Nebula (NGC 3293). Both Gem and Wishing Well are objects located between the Southern Cross and the False Cross.
The Gem Nebula is small and you can clearly see one red giant star, that stands out. It is a very beautiful cluster, that is similar to the Jewel Box but often overlooked because it's close to Eta Carinae.
Same sky we look at now in January at midnight will be visible earlier and earlier throughout the month.
We are now shifting to NGC 2546 in the Milky Way, just a bit away from the False Cross, a bit to the left of it, in Puppis.
For the grand finale we looked at the really hard to see globular clusters in Musca, which now is almost at 2 o'clock from the Southern Cross. The sky is so clear that we can see Omega Centauri very easily with the naked eye. NGC 4833 is a lovely globular cluster about 6.9 magnitude where we can resolve stars to the centre, it has a tiny star at the side. Then we look at another fainter glob mag 7.2 NGC 3472, quite big and we can see the diffuse cloud-like smudgy pattern, but on top there are many stars we can resolve, a faint glob - compared to everything else we've been looking at.
Next we go to another galaxy near Sculptor close to the star Deneb Kaitos. This one is a faint galaxy, elongated, pretty faint, and a few stars in front of it. NGC 247, a 9.1 spiral galaxy.
Now we look for another glob, NGC 288, a magnitude 8.1 globular cluster visually just beyond sculptor galaxy. Very faint, surrounding it is a group of stars similar to Corona Borealis but the telescope version.
Grus is now closing to the horizon, 10 degrees , with all its visually double stars, looking like a necklace.
Tonight we have seen beautiful things in the sky and shared them and this amazing New Zealand night sky, where the milky way is so bright, it's been a great night, with more galaxies than you can poke a stick at, a really great night.
Thank you to Stonehenge Aotearoa for letting us plant our telescopes in their field and to Rhian Sheenhan for the use of his amazing music - which we always listen to when we do observing.
We wish you clear skies from New Zealand.
Hari and Sam
Odds and Ends
Betelgeuse, normally one of the brightest stars in the night sky, has been gradually dimming since October 2019 to the extent that it's now dimmer than neighbouring Aldebaran. This has caused some interest in the astronomy community, as Betelgeuse is a red supergiant near the end of its lifespan, and it's believed that its eventual supernova explosion might be heralded by dimming like this. With that said, Betelgeuse is naturally variable, and it's believed that the current historic low may be due to two separate dimming processes reaching minima simultaneously rather than necessarily being a sign of an upcoming supernova, as while Betelgeuse is expected to explode soon in astronomy terms, it might live for another 100,000 years before doing so.
Referenced in the audio was an xkcd What If? discussion on supernova brightness, which can be found here.
Emma talks about Jodrell Bank's connection over the years to Doctor Who, prompted by a recent mention of the observatory by the show. Very mild spoilers for if you haven't seen the first two episodes of Series 12! The connection goes back many years, with the most notable being Tom Baker's Doctor falling from a model of the Lovell telescope (and subsequent regeneration). But was it the Lovell Telescope, or was it the mysterious Pharos Project…?
Fast radio bursts (FRBs) are one of the big mysteries in radio astronomy, and we need all the info about them we can get! This episode, we talk about a recent result (Nature and ArXiv) where astronomers pin-point the origin of an FRB (only the fourth ever FRB localised to its host galaxy) to a spiral galaxy like the Milky Way.
|Interview:||Alexandre Lazarian, Roke Cepeda-Arroita and Mariam Rashid|
|Night sky:||Ian Morison and Haritina Mogosanu|
|Presenters:||Fiona Porter, Emma Alexander, and Laura Driessen|
|Editors:||Adam Avison, George Bendo, Tiaan Bezuidenhout, Hongming Tang, and Joseph Winnicki|
|Segment Voice:||Tess Jaffe|
|Website:||Fiona Porter and Stuart Lowe|
|Cover art:||A plume on Betelgeuse (artist's impression) CREDIT: ESO/L. Calcada|