On May 17th the automated Lick Supernova Search discovered the SN 2012cg supernova in galaxy NGC 4424 in the constellation Virgo. From 18th magnitude it has now brightened to 12.0 and rivals the core of the galaxy for brightness. This exploding star was originally a White Dwarf star equivalent in mass to our own Sun and locked in a binary orbit with a much larger star. It steadily drew matter from this companion star up to a point where it became unstable, collapsed in on itself and exploded, producing what is known as a Type Ia supernova. This spectacular event should be visible in telescopes of 6″ diameter and above.
Image taken Sunday June 11th 00.59 am from Nerpio, Spain with iTelescope T7 Planewave 17″ CDK, SBIG STL-11000M. 300 sec Bin 2. RA: 12h 27m 11.9s DEC: 09° 25′ 01″ (J2000)
Its after midnight over here in the UK and there will be cloud 5-6 am so no chance of seeing the transit for me. I popped over to the NASA Live stream here http://sunearthday.nasa.gov/webcasts/nasaedge/ for a view and was surprised to see that the images are actually being broadcast via views from readily available amateur solar telescopes. Andy Lunt of Lunt Solar Systems http://www.luntsolarsystems.com/ was explaining the different wavelengths of light that we can view the transit in including Hydrogen Alpha (red), Calcium K (purple blue) and White Light (how we would see it in natural light if it wasn’t so bright – NOTE do not look at the sun directly ! ). I took a set of screenshots from the live feed so that you can see what is going on. It gives you a great impression of the size of the planet Venus relative to the size of the Sun. Earth would typically fit into one of those larger sunspots you can see to the left.
Views courtesy of NASA Live view from Mauna Kea, Hawaii
White Light view 00.21 UT
Calcium K view 00.34 UT
Hydrogen Alpha view 1.45 UT
Above: NASA images of the transit of Venus in 2004
As many of you will know the planet Venus traverses across the face of the sun for 7 hours during the evening of June 5th and very early morning of June 6th 2012 (in the northern hemisphere). This event will not happen again for another 105 years so it truly is a once in a lifetime event. I’m not optimistic of a view from my location as it will only be visible between 5.00 and 5.54 am at less than 10 degrees elevation on the horizon, so it needs a perfectly cloud free view from an elevated site to have the best opportunity and we normally have 78% cloud in early June ! Nevertheless, i’ll be out there with the solar telescopes if it looks at all favorable
If anyone is trying to find out whether the transit will be visible from their location in the northern hemisphere I can recommend the following website http://transitofvenus.nl/wp/where-when/local-transit-times/ which has a handy graphical visibility calculator that is very easy to use. Just pop your postcode into the search box or drag the map to your location.
If the timezones and cloud conspire against you then I can recommend the NASA live broadcast page where you can follow the event in real-time http://venustransit.nasa.gov/transitofvenus/ Another good broadcast site which will be using multiple locations across the globe and telescopes viewing the sun in various wavelengths of light is the Columbus State University site here http://www.ccssc.org/transit2012.html
Hope you all get a view of this rare event. Please remember not to look directly at the sun and do take appropriate safety measures before viewing with the correct equipment. Do get in touch if you have some images and i’ll post them up on the blog – good luck !
Above: Berkeley 20 Open Cluster in Orion. Imaged with iTelescope T3 7/10/11 4:06:04 am New Mexico time (UTC -7) RA: 05h 32m 36.0s DEC: 00° 11′ 11″ (J2000) TAK TOA 150, SBIG ST2000 SMC 2x 600 sec Bin 1
Yes I know this isn’t one of the most exciting photographs visually, but that little knot of stars just to the right of centre is one of the top 20 in terms of the oldest star clusters in our galaxy (6 billion years old) and one of the most distant (15.8 kiloparsecs or 51,000 light years). Along with Berkeley 29, which currently holds the record for the most distant open cluster in our galaxy at 22.6 kpc or 73,000 light years, these veteran star communities are providing exciting new evidence for the formation of the outer disk of the Milky Way and perhaps even suggest that our galaxy may be a cannibal !
Current research using photometry and spectroscopy of the stellar makeup of these and a number of other distant clusters (Berkeley 31, NGC 2141, NGC 2808, NGC 5286) suggests that something odd is going on. While they typically have low iron metal content this content should decrease the further you get from the galactic centre, but recent papers have suggested that beyond 40,000 light years the iron content bottoms out and actually remains constant out to the edge of the galaxy at about 30% of the Sun’s iron content. On top of that the clusters have stars with a high Oxygen/Magnesium to Iron ratio which is a signature derived from short-lived massive stars that have gone supernova, so what is going on ? An intriguing possibility is that these distant open clusters may be aliens in our midst, derived by our galaxy either swallowing up the stars from another galaxy in a merger event, or stars accreting to the outer disk of the Milky Way in a collision event with a passing gas cloud that triggered new star formation.
Evidence is also gathering that these older clusters lie in a dispersed arc-like structure in the outer disk known as the Galactic Anti-center Stellar Structure (GASS), sometimes called the Monoceros Ring. It is thought that this structure could be the remnant of a merger with a dwarf galaxy about 5 billion years ago, similar to the Canis Major dwarf spherical galaxy that was discovered to be merging with our galaxy back in 2003.
Above: Berkeley 29 Open Cluster in Gemini – the most distant open cluster in the Milky Way. Imaged with iTelescope T3 7/10/11 5:01 am New Mexico time (UTC -7) RA: 06h 53m 04.0s DEC: 16° 55′ 39″ (J2000). TAK TOA 150, SBIG ST2000 SMC 2x 600 sec Bin 1
With the advent of the 4.1 metre VISTA infrared telescope coming online at the European Southern Observatory last year we may soon discover older and more distant open clusters that will fill out this picture of early galactic evolution. Up to September 2011 VISTA had discovered 96 new clusters previously hidden by thick dust clouds and it is estimated that there may be as many as 30,000 open clusters still waiting to be found in our galaxy – exciting times ahead !!
If anything I reckon the planetary conjunction of the Moon, Venus and Jupiter in the west looks even better tonight with Venus close to the Moon. I couldn’t resist another photo, but this time in full darkness. Although I didn’t realise it at the time I managed to catch the Pleiades star cluster right at the top of the image, which really enhances the overall alignment.
Image taken 26/3/12 at 9.48pm Canon 350D, F5, ISO 400, 10 seconds @ 42mm
Supernova SN 2012aw is a Type IIP and clearly visible in galaxy M95 in the constellation Leo at magnitude 12.7. It was discovered by The Italian Supernovae Search Project on 16/3/2012 and has rapidly brightened from its discovery magnitude of 15. The original star is thought to have been a red supergiant about 8 times more massive than the sun. This star used up all of its nuclear fuel then collapsed in on itself under intense gravitational forces and at speeds approaching 45,00 miles per second. When the outer layers smashed into the core they crushed it and this sent a massive shock wave back out towards the surface, tearing the star apart in the process and creating the bright supernova that we see. The supernova appears to have reached its maximum brightness now and will probably fade over the coming weeks. It can easily be seen in telescopes of 4″ and greater diameters from good observing locations. Image taken 25/3/12 8.55 local time via iTelescope.net T07 in Nerpio, Spain. Planewave 17″ CDK, SBIG STL-11000M, 3 x 300 sec Bin 1. RA: 10h 43m 59.9s DEC: 11° 42′ 00″ (J2000)
There are some great views in the west right now (yes now, get out there !) of a close planetary alignment between the Moon, Jupiter to the left and Venus above the Moon. The Moon is in a thin crescent phase too so you get the added benefit of that slightly blue-grey ghostly disk on the dark side of the Moon resulting from the earthshine effect ie. the reflection of sunlight from the Earth’s surface to the Moon. The alignment is particularly good tonight and tomorrow so do have a look. Image taken 25/3/12 8:30pm. Canon 350D, ISO 400, 18mm, 0.6 sec exposure.
Huge active region AR1429 is looking rather benign now as it nears the western limb of the sun’s disk, but just five days ago it produced the largest solar flare of the current solar cycle, an X5 class eruption at 00:28 UT on the 7th March. On the 9th and 10th March it continued to flare at M class levels and large Coronal Mass Ejections (CME’s) were hurled our way on each occasion which will soon be providing plenty of aurora activity in the northern polar regions. Fortunately the cloud parted this afternoon to give me a clear view of this impressively active sunspot group so I took the opportunity to capture it in the CaK and Ha light wavelengths. The hydrogen alpha views show a huge curving filament snaking across the eastern limb. Images taken 12.32- 13.09 UT using Coronado Ha PST/Lunt CaK wedge at 100mm/DMK 41 camera
CAK views of AR 1429:
Hydrogen Alpha Views:
The Type II supernova 2012A was first recognised by Bob Moore, Jack Newton, and Tim Puckett during an automated search on January 7th using a 16″ reflector when its magnitude was estimated at 14.6. This is the first supernova of 2012 and it is located in the irregular galaxy NGC 3239 (Arp 263) in the constellation Leo. The galaxy has an apparently chaotic shape which is the result of two galaxies colliding and merging. By January 27th the supernova had increased in brightness to 13.4 mag and has now faded back to around mag 14.4 in the above image. The light from this supernova has taken 25 million years to reach us !
The AAVSO light curve for SN 2012A is shown below……
Image taken 9.24 pm 28/2/12 at Nerpio, Spain (UTC+1) on T7 (Planewave 17″ CDK Dall-Kirkham Astrograph,SBIG STL-11000M) RA: 10h 25m 05.9s DEC: 17° 10′ 01″ (J2000) 25 minutes exposure. Bin 1 @ 2 x 600 and 1 x 300 seconds.
The blue arrow marks the asteroid 97 Klotho passing through the constellation Virgo on 26/2/12 at 4.46am New Mexico time (UTC -7). First discovered by E.W. Tempel in Marseille on 17th February 1868 Klotho is a main-belt asteroid with a diameter of 82.83 km. It rotates 35 times per hour and has an absolute magnitude of 7.63. In this image Klotho has just passed the large red star HIP 61658 and to the top right you can see the spiral galaxy NGC 4536 with the much fainter NGC 4533 galaxy above it. The asteroid was named after one of the three Fates (Moirae to the Greeks, Parcae to the Romans), Klotho, who carried a spindle and a globe and spun the thread of life. The other Fates were Lachesis and Atropos. T20 1 x 600 sec. RA 12:37:49 DEC 1:44:20
The image below shows the orbital track of this asteroid through the solar system marked in blue….