THE SOUTHWORTH PLANETARIUM
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Founded January 1970
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THE DAILY ASTRONOMER
Tuesday, May 3, 2016
A May Messiers!
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HAPPY BIRTHDAY, A.A.A.!
You know who you are.
Send that question!
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When perusing a star chart, one quite expects to see stars, which most often appear as black dots imprinted on white paper. A more elaborate chart would also include a grid allowing users to pinpoint a celestial object's precise location. a magnitude key indicating each star's brightness and M-objects. These are Messier objects and are listed with a capital M followed by a number, such as M13, M31 or M42. M-objects are named for French astronomer Charless Messier (1730-1817). Messier was an avid comet hunter who observed many celestial objects that resembled comets when viewed telescopically. Realizing that other comet hunters might be similarly frustrated when finding these imposters, Messier compiled a catalog of prominent celestial bodies that other astronomers might mistake for comets.
This chart features the Messier Objects within the Virgo region. Each Messier object is denoted with a capital M and a number. This number indicates the object's position in the Messier Catalog.
Today,
we look at a beautiful "May Messier," defined as a Messier object that is visible most of the night in May. During the next DA school year (Sept 1, 2016 - Aug 4, 2017),
we will
attempt to examine every single Messier object as a way to commemorate
the 200th anniversary of Charles Messier's passing. For now, we
think a single Messier will suffice
Look at the bottom of the above star chart and notice the object labeled M104: the Sombrero Galaxy. Here, deeply imbedded within the depths of Virgo is a distant galaxy notorious for its furiously energetic core. Its circular disk and bulging center lend it an appearance of Mexican head wear, hence the name.
M104: The Sombrero Galaxy. An unbarred spiral galaxy within the constellation Virgo the Maiden. Astronomers believe that this distant galaxy might conceal a gigantic black hole in its nucleus.
M104 is classified as an "unbarred spiral," meaning that its nucleus is more spherical than bar-shaped. Our Milky Way is a barred spiral galaxy in which spiral arms radiate away and curl around a central bar. The Sombrero is as bar less as Prohibition era Kentucky. Like most galaxies, the Sombrero's nucleus harbors a super massive black hole. Astronomers estimate its mass to be about one billion times greater than the Sun's. They can measure this mass by measuring the velocities of surrounding stars. The faster the stars. the greater the mass of the black hole they're orbiting.