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Triangulum Galaxy. Alex Roberson. Location. 3 million light years from earth Located in Triangulum constellation. Name. Catalogued as Messier 33 or NGC 598 Sometimes called the Pinwheel Galaxy; a nickname shared with Messier 101. Visibility.
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Triangulum Galaxy Alex Roberson
Location • 3 million light years from earth • Located in Triangulum constellation
Name • Catalogued as Messier 33 or NGC 598 • Sometimes called the Pinwheel Galaxy; a nickname shared with Messier 101
Visibility • Under good conditions, it can be seen with the naked eye. • It is one of the farthest galaxies that can be seen with the naked eye.
Discovery • Most likely discovered by Giovanni Battista Hodierna before 1654 • In his work De systemateorbiscometici; dequeadmirandiscoelicaracteribus he described it as a cloud-like nebula or obsuration and gave the description, "near the Triangle hincinde".
Second discovery • It was discovered again by Charles Messier. • He listed it in his book Catalog of Nebulae and Star Clusters as number 33.
Properties • It has a diameter of about 50,000 lightyears • It is the third largest member of the Local Group • It may be gravitationally bound to the Andromeda galaxy
Local Group • The local group consists of around 30 galaxies. • Its gravitational center is somewhere near the Milky Way and the Andromeda Galaxy.
Stars • It contains about 40 billion stars • The Milky Way contains around 400 billion • The Andromeda Galaxy has over 1 trillion
The Disk • The disk of Triangulum has an estimated (3-6) × 10^9 solar masses • Its gas is around 3.2 x 10^9 • Combined mass of everything in the galaxy is 10^9
Distance • Three techniques have been used to measure distances to M 33. • Using the Cepheid variable method, an estimate of 2,770 ± 130 kly (850 ± 40 kpc) was reached. • The Tip of the Red Giant Branch (TRGB) method was used to derive a distance estimate of 2,590 ± 80 kilolight-years (790 ± 25 kpc).
Structure • In astronomer Gérard de Vaucouleurs' revised Hubble Sandage system of galaxy morphological classification, the Triangulum galaxy is classified as type SA(s)cd. • The S basically means it is a spiral galaxy • The A means “ the galactic nucleus lacks a bar-shaped structure”. • Astronomer Allan Sandage's "(s)" is used when the spiral arms emerge directly from the nucleus or central bar. • The cd means it has loosely wound arms.
Inclination • It has an inclination of 54° when viewed from the Earth. • This allows it to be viewed without much obstruction from gas and dust.
Star formation • It has a higher rate of star formation than the Andromeda Galaxy. • The rate of star formation is about 3.4 Gyr^−1 pc^−2 • This is about 0.45 ± 0.1 solar masses per year
Star Formation History • Due to differing gradients, there is a different star formation history between the inner and outer disks. • This occurs when gas is accumulated at large radii later in a galaxy's life span, while the gas at the core becomes depleted. The result is a decrease in the average age of stars with increasing radius from the galaxy core
Discrete Features • A total of 515 discrete candidate sources of 24 μm emissions have been discovered as of 2007. • The brightest of them lie within the central region of the galaxy. • Many of these are associated with HII regions. • The four brightest are NGC 588, NGC 592, NGC 595 and NGC 604.
Sources • Wikipedia