Search results
Results from the WOW.Com Content Network
The first known globular cluster, now called M 22, was discovered in 1665 by Abraham Ihle, a German amateur astronomer. [4] [5] [6] The cluster Omega Centauri, easily visible in the southern sky with the naked eye, was known to ancient astronomers like Ptolemy as a star, but was reclassified as a nebula by Edmond Halley in 1677, [7] then finally as a globular cluster in the early 19th century ...
It contains 274 known variable stars, by far the most found in any globular cluster. These include 133 RR Lyrae variables , of which about a third display the Blazhko effect of long-period modulation.
Home to over 100,000 stars,the cluster is notable for containing a large number of variable stars (112) and pulsars (8), including one double neutron star system, M15-C. It also contains Pease 1, the first planetary nebula discovered within a globular cluster in 1928. [12] [13] Just three others have been found in globular clusters since then. [14]
Based on the method of comparing the luminosities of globular clusters (located in galactic halos) from distant galaxies to that of the Virgo Cluster, the globular cluster luminosity function carries an uncertainty of distance of about 20% (or 0.4 magnitudes).
The brightest star in the cluster is a red giant, the variable star V11, also known as V1554 Herculis, [16] with an apparent visual magnitude of 11.95. M13 is 22,200 to 25,000 light-years away from Earth , [ 9 ] and the globular cluster is one of over one hundred that orbit the center of the Milky Way.
Messier 4 or M4 (also known as NGC 6121 or the Spider Globular Cluster) is a globular cluster in the constellation of Scorpius. It was discovered by Philippe Loys de Chéseaux in 1745 and catalogued by Charles Messier in 1764. [9] It was the first globular cluster in which individual stars were resolved. [9]
These new-found star clusters contain hundreds of thousands of stars, a similar number to globular clusters. The clusters also share other characteristics with globular clusters, e.g. the stellar populations and metallicity. What distinguishes them from the globular clusters is that they are much larger – several hundred light-years across ...
Messier 70 or M70, also known as NGC 6681, is a globular cluster of stars to be found in the south of Sagittarius. [a] It was discovered by Charles Messier in 1780. [b] [6] The famous comet Hale–Bopp was discovered near this cluster in 1995. [10] [c] It is about 29,400 [4] light years away from Earth and around 6,500 light-years [11] from the ...