Interview with Dr Miguel Pérez-Torres
We talk to Dr Miguel Pérez-Torres about observing supernovae using radio telescope arrays. He explains how high-resolution radio observations of exploding stars, or supernovae, are very useful in studying their properties in more detail, and discusses some of the observations he is doing with the E-Merlin array He also talks about so-called 'supernova factories': young, dusty galaxies that produce stars at a high rate. He wraps up by discussing the future of radio supernovae observations and hints at some interesting observations of the latest supernova to be discovered, 2014J.
The Night Sky
Ian Morison tells us what we can see in the northern hemisphere night sky during March 2014.
Orion, Taurus, Canis Major and Gemini move into the western sky after sunset. Cancer is further east, and binoculars can be used to find the open cluster M44 - the Beehive Cluster - in this otherwise sparse area of the sky. Leo is rising in the east, and a number of galaxies can be found beneath his belly using a telescope. Virgo and Coma Berenices are lower down, and share a region known as the Realm of the Galaxies, wherein lies the giant Virgo Cluster. Boötes rises a little later, with its bright star Arcturus. Ursa Major, containing the Plough, is up to the north, and the rear two stars of the the Plough, Merak and Dubhe, point towards the North Star.
- Jupiter is still well placed for viewing in the evening, reaching above 60° elevation. It shines at magnitude -2.4 and lies in Gemini, its retrograde (westward) motion reverting to a normal eastward progression on the 6th of the month and leaving it near to the star Mebsuta. A small telescope can pick out the four Galilean moons and, at certain times, the Great Red Spot in the planet's South Equatorial Belt.
- Saturn rises around midnight Universal Time (UT) at the start of the month and 22:30 UT by the end (bearing in mind that the clocks go forward one hour in Europe on the 30th). It is in Libra, and, during March, brightens from magnitude +0.4 to +0.3 and grows in angular diameter from 17.4 to 18.4". The planet begins retrograde motion on the 3rd as the Earth overtakes it in their orbits. Saturn's rings lie at 23° to the line of sight, allowing features such as Cassini's Division to be seen with a small telescope or the Enke Gap with a larger one. However, Saturn does not get very high in the northern hemisphere sky at present.
- Mars is in Virgo, rising at about 22:00 UT at the beginning of the month and two hours earlier by month's end. Its brightens from +0.5 to -1.3 in magnitude during March, and grows from 11.6 to 14.6" in diameter as it approaches opposition (opposite the Sun in the sky) on the 8th of April. Its disc is about 91% illuminated, and surface features such as the north polar cap (tilted at 19° to our line of sight) can be seen with a telescope. Mars spends the month a few degrees from the bright star Spica as it moves retrograde across the sky.
- Mercury reaches western elongation (its greatest separation from the Sun in the sky) on the 14th. It can be seen rising in the east-south-east about half an hour before sunrise, and its disc is 7.5" across and 50% illuminated in the middle of the month. The planet brightens from +0.8 to -0.1 during March, but cannot be seen very high in the sky.
- Venus reaches western elongation on the 22nd, and can be seen about 25° above the south-eastern horizon before sunrise. It dims slightly from magnitude -4.8 to -4.4 this month, and shrinks from 32 to 22" across while its illuminated fraction increases from 36 to 54%.
- It is still a good time to observe Jupiter in the evening this month. Its angular size drops from 42 to 38" during March, but you can still see many features through a small telescope, and the planet reaches its highest point in the sky relatively early in the evening.
- The constellations of Cassiopeia and Perseus are high in the west in the evening this month, allowing the Perseus Double Cluster to be found along the path of the Milky Way that runs between them. The star Algol, in Perseus, can also be seen to 'wink' roughly every 2 days and 21 hours, leading it to be nicknamed 'the Demon Star'. In fact, it is a binary star system in which the two stars occult each other in their orbits, causing the dips in apparent brightness.
- The asteroid Pallas can be located in the first week of March, when it approaches the second-magnitude star Alphard in Hydra. Its magnitude of +7 makes it easily visible in binoculars, and can be observed to move north night by night.
- Mars is only 4° from a nearly-full Moon in the south-eastaround 23:00 UT on the 18th, and the star Spica is only 1° away from the Moon as well.
- Saturn is about 2° from a waning Moon in the south-east around midnight UT at the end of the 20th
- Venus is less than 3° below a waning crescent Moon in the south-east one hour before dawn on the 27th.
Odds and Ends
The MIDAS project has published results from last September of a meteroid impact on the surface of the moon. The meteoroid would probably have measured between 30 cm and 1.4 m, and weighed between 45 kg and 450 kg. It left a crater roughly 45 m in diameter, and the impact produced a glow that lasted 8 seconds. Read an Ars Technica article on the story here. The original MNRAS journal article can be found here.
NASA's Kepler mission has recently announced a haul of 715 new exoplanets, taking the count of confirmed planets to almost 1,700.The 715 orbit just 305 stars, and were confirmed using a technique called verification by multiplicity, which focuses on finding multiple planets around one star. 95 percent of the new planets are smaller than Neptune, and four are less than 2.5 times the size of the Earth and in the habitable zone of their parent star.
Spectacular aurorae were seen over northern Europe late on the 27th of February (Universal Time). The Northern Lights extended much further south than usual, producing displays in much of the United Kingdom and Ireland. Particles ejected by the Sun early on the 25th were responsible, but their effect was unexpectedly strong as they struck molecules in the Earth's atmosphere to produce green and, more unusually, red colours. The Southern Lights were also seen by astronauts on the International Space Station. Alert services, such as Aurora Watch UK, are available to forecast upcoming aurorae.
|Interview:||Dr Miguel Pérez-Torres and Indy Leclercq|
|Night sky:||Ian Morison|
|Presenters:||Fiona Healy, Indy Leclercq and Mark Purver|
|Editors:||Sally Cooper, Indy Leclercq and Mark Purver|
|Segment Voice:||Iain McDonald|
|Website:||Indy Leclercq and Stuart Lowe|
|Cover art:||The peculiar galaxy Arp 299 seen by the Hubble telescope.It is the result of the collision and merger of two spiral galaxies; several supernovae can be found here. CREDIT: NASA/ESA/Hubble Heritage (STScI/AURA)/A. Evans (UVa/NRAO/Stony Brook U.)|