A Twinkle of Stardust - Globular Star Clusters

Messier 13 - NGC 6205 - The Great Globular Cluster in the constellation Hercules
Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"Messier 13 is one of the show piece astronomical sights visible from the Northern Hemisphere. It may be seen as a small fuzzy patch of stardust through 10x50 binoculars and is easily resolved to show stars in small amateur telescopes. M 13 is estimated to be 22,000 light years distant, to have a diameter of 145 light years and a mass of 600,000 solar masses. It  is mainly composed of ancient stars but because of the stellar density at its core, collisions between stars occur to produce new stars. These relatively new stars are called 'Blue Stragglers'. The age of Messier 13 is estimated as 11.66 billion years". - Kurt Thrust-acting CEO and current Director of the Jodrell Plank Observatory.

 "Globular Star Clusters are spherical collections of stars held together by mutual gravitational attraction that orbit our galactic core in the galactic halo as satellite star systems. We know of some 150 globular star clusters associated with the Milky Way and it is thought that many remain to be discovered. Other galaxies with sufficient mass have attendant globular star satellite systems and some large and ancient elliptical galaxies like Messier 87 have as many as thirteen thousand globular star clusters. There is evidence that globular star clusters may be lost and gained by tidally interacting galaxies.  Towards the cores of globular star clusters star densities increase -100 to 1000 stars per cubic parsec (1 cubic parsec = approx 35 cubic light years) - By and large globular star clusters are composed of  'metal poor' (comprised of hydrogen and helium) and old stars. Intermediate sized black holes and millisecond pulsars have been discovered within globular star clusters." -  Archie Mendes - visiting theoretical astronomer at the Jodrell Plank Observatory
 

Messier 92 - NGC6431 - Globular Star Cluster in the constellation Hercules - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"Messier 92 is a personal favourite and looks quite beautiful through the eyepiece when viewed with the observatory 127 mm. refracting telescope. It is a very old globular cluster with an age roughly the same as the Universe (13.8 billion years). It is composed of low metal stars and is estimated to be 26,700 light years distant. M 92 has a mass equivalent to 330,000 solar masses and a diameter of 110 light years". - Kurt Thrust-acting CEO and current Director of the Jodrell Plank Observatory.

Messier 4 -NGC 6121 - Globular Star Cluster in the constellation Scorpius -Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert 

"The constellation Scorpius is only observable from the Jodrell Plank Observatory during summer months and never rises high above our southern horizon. It is however very easy to locate from the southern hemisphere as it lies close to the bright red star Antares. It is a loosely concentrated cluster containing more than 100,000 stars with a mass  equivalent to 67,000 solar masses. It features a characteristic bar across its core which was first noted by William Herschel in 1783. It has a diameter of 70 light years and an estimated age of 12.2 billion years. The results of investigation into the metal content of the stars in M 4 indicate the presence of two stellar populations". - Adelaide Darwin- post-grad research assistant at the Jodrell Plank Observatory.

Messier 3 - NGC 5272- Globular Star Cluster in the constellation Canes Venatici - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"Messier 3 is easily visible in binoculars from a dark site if you look about midway between the bright stars Arcturus and Cor Caroli. M3 contains approximately 500,000 stars with an equivalent mass to 450,000 suns.  M 3 contains an unusually high proportion of variable stars - 274 known to exist. It has a diameter of 180 light years and is estimated to be 33,900 light years distant. It is younger than both M 13 and M 92 with an age estimated as 8 billion years. M 3 is also relatively 'metal rich". - George Hammer - Jodrell Plank Observatory resident Geologist

Messier 80 - NGC 6093 - Globular Star Cluster in the constellation Scorpius - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"Messier 80 has a diameter of 95 light years and contains at least two thousand stars with a combined mass equivalent to 502,000 solar masses. It has an estimated age of 12.54  billion years and is some 32,600 light years distant. M 80 is one of the most dense of the 147 known globular star clusters orbiting the Milky Way and contains a high number of 'Blue Stragglers'. - Adelaide Darwin- post-grad research assistant at the Jodrell Plank Observatory.

Messier 5 - NGC 5904 - Globular Star Cluster in the constellation Serpens -Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert 

"Readily seen in binoculars this globular star cluster may be seen with the naked eye from particularly dark sites. It is 165 light years in diameter, contains between 100,000 and 500,000 stars with a mass equivalent of 857,000 suns and is at a distance of 24,500 light years. The cluster is 13 billion years old, has many red giant,variable and white dwarf stars and a number of 'Blue Stragglers." - Kurt Thrust-acting CEO and current Director of the Jodrell Plank Observatory.

Messier 9 - NGC 6333 - Globular Star Cluster in the constellation Ophiuchus -Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert 

"Messier 9 is one of the nearer globular star clusters to our galactic core. It is 5,500 light years from the centre of the Milky Way but some 25,000 light years distant from Earth. It contains more than 250,000 stars with low metal content. The cluster is 90 light years in diameter, has a mass equivalent to 422,000 solar masses and is 12 billion years old. No 'Blue Stragglers' have been discovered in this cluster" - Kurt Thrust-acting CEO and current Director of the Jodrell Plank Observatory.

Messier 28 - NGC 6626 - Globular Star Cluster in the constellation Sagittarius - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

" Sagittarius rarely rises above the southern horizon from Lowestoft so imaging this particular globular cluster from the Jodrell Plank Observatory is not practicable. M 28 is 17,900 light years distant, contains more than 50,000 stars, has a mass equivalent to 551,000 suns and a diameter of 60 light years. A number of variable stars and 12 millisecond pulsars have been detected in this globular cluster". - Adelaide Darwin- post-grad research assistant at the Jodrell Plank Observatory.

Messier 53 - NGC 5024 - Globular Star Cluster in the constellation Coma Berenices - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"Messier 53 is one of the more distant of the Milky Way globular clusters lying more or less equidistant from the galactic core and Earth at approximately 60,000 light years. This is a metal poor cluster comprised, unlike many other of the globular star clusters, from many red giant 'first generation' stars. The majority of globular star clusters are dominated by 'second generation' stars. 'First generation' stars are stars which did not form from gas and dust recycled from previous generations of stars. M 53  contains at least 500,000 stars and has a mass equivalent to 826,000 solar masses. It is the most northern globular star cluster found to date. M 53 has an estimated age of 12.67 billion years and a diameter of 220 light years (approximately one fifth of the diameter of the Milky Way)" -  Archie Mendes - visiting theoretical astronomer at the Jodrell Plank Observatory

Palomar 4 - Globular Star Cluster in the constellation Ursa Major - Credit: COAST Robotic Telescope - telescope.org - Open University - Pip Stakkert

"This cluster is further out from our galactic core than the Magellanic Clouds  and at least 65,000 light years. It was first discovered on the photographic plates taken at the Mount Palomar Observatory by Edwin Hubble in 1949. It was rediscovered independently in 1955 by A G Wilson. It was first thought to be a dwarf galaxy but was later recognised to be a giant globular star cluster in the outer reaches of the galactic halo. A number of the stars in this cluster have been observed to be variable" - Kurt Thrust-acting CEO and current Director of the Jodrell Plank Observatory.

Credits: Wikipedia, Messier Objects

'Star-man' - In memory of  Martin Richard Johns - 1950-2019