Wednesday, May 24, 2023

4021 - STARS HAVE NAMES ?

 

-    4021  -  STARS  HAVE  NAMES?  -    This is a quiz.  Can you name these 10 stars and their constellations?


----------------------------   4021  -  STARS  HAVE  NAMES ?  Sagittarius black hole?

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----------  (1)  Most popular star?

----------  (2)  Most powerful star?

----------  (3)  The brightest star?

----------  (4)  The biggest star?

----------  (5)  The smallest star still burning hydrogen?

----------  (6)  The closest star?

----------  (7)  The smallest star possible?

----------  (8)  The star most likely to go supernova next?

----------  (9)  The fastest star?.

----------  (10)  The first star found to have a planet?

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--------------  Here are the answers:

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-----------  (1)  Most popular star is Polaris the North Star, Constellation Ursa Minor

----------  (2)  Most powerful star is Eta Carina, Constellation Carina

----------  (3)  The brightest star is Sirius the Dog Star in Constellation Canis Majoris

----------  (4)  The biggest star is VY Canis Majoris

----------  (5)  The smallest star still burning hydrogen  is a Red Dwarf

----------  (6)  The closest star is Proxima Centauri in Constellation Centauris

----------  (7)  The smallest star possible is a White Dwarf

----------  (8)  The star most likely to go supernova next  Betelgeuse in the Constellation Orion

----------  (9)  The fastest star in the Constellation Hydra

----------  (10)  The first star found to have a planet is 51 Pegasus in the Constellation Pegasus

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----------  (1)  Most popular star is Polaris the North Star, Constellation Ursa Minor.( The Bear Cub).  Polaris is the North Star and the star most often found in all our literature.  It is a stationary star in the northern sky because the Earth’s rotational pole points nearly directly at it.  Polaris is in the “Little Dipper” called the Constellation Ursa Minor.  It is 430 lightyears away.  Magnitude 1.97.  It is actually a system of 3 stars.  A Supergiant of 6 Solar Mass and at 2,400 AU away there is another star and a third a t 18.5 AU.

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-  All the circumpolar stars rotate around Polaris as the world turns.  the rotation axis of a spinning Earth wobbles like a spinning top.  the wobble is called precession.   In 12,000 B.C. Vega was the North Star and will again be our pole star in another 12,000 years.

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----------  (2)  Most powerful star is Eta Carina, Constellation Carina ( The Keel of Argo Navis)..  Take the time to see the Hubble picture of Eta Carinae if you have never seen it.  It is spectacular.  Eta Carinae  is 8,000 lightyears away. Magnitude 6.21, so visible with the naked eye.  It is a 2 star system with an enormous nebula created by a supernova that did not quite go all the way.  Its total luminosity is 4,000,000 times that of our Sun.  Mass is 100 Solar Mass.  It should explode into a real supernova any day now.  Of course, if it exploded 7,999 years ago we would not see it until next year.  Its last eruption that created the spectacular nebula reached us in 1843.  Eta Carinae is classified as a Luminous Blue Variable Binary Star.

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----------  (3)  The brightest star is Sirius the Dog Star in Constellation Canis Majoris. (The Greater Dog).    Sirius is Magnitude -1.48.  It is twice as bright as the next brightest star Canopus.  Sirius is a Red Giant star , a binary with a White Dwarf companion star.  It is 8l6 lightyears away and so bright because it is so close.  It is 300,000,000 years old.

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-  The rising of Sirius in the Southern sky marked the flooding of the nile River fo the Ancient Egyptians.  Sirius was the 1st star to have its velocity measured with the Doppler Redshift  Sirius, Procyon and Betelgeuse are the vertices of the Winter triangle.  Sirius, the 5th closest star, can even be seen in the daylight under the right conditions.  25 times luminosity of the Sun, abbreviated Ls.     Solar Mass 2.1.  20 AU away is White Dwarf 0.6 Solar Mass orbiting every 49.9 years.

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----------  (4)  The biggest star is VY Canis Major a hyper giant star with a radius of 2,600 times our Sun’s.  It is 4,900 lightyears away.  A single star of Magnitude 8.  It radius would extend all the way out to the orbit of Saturn.  It would tale light 8 hours to travel around the star’s circumference.  (It would take light 14.5 seconds to travel around our Sun.)   It would take 7,000,000,000,000,000 Earth’s to fill the volume of Canis Major.(The Greater Dog).    It is 450,000 times the Sun’s luminosity.

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----------  (5)  The smallest star still burning hydrogen  is a Red Dwarf.   The name is MOA-2007-BLG-192L in the Constellation Sagittarius.  9% Solar Mass.  If it were 6% Solar Mass it would stop nuclear fusion and be a “ Brown Dwarf”.  The Red Dwarf is 100 times brighter than a Brown Dwarf, but, 1,000 times fainter than the Sun.   It would be about 100 Jupiter mass with 1.2 times the radius of Jupiter.  It would be very dim and dimmer still if it evolved to a Brown Dwarf.

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----------  (6)  The closest star is Proxima Centauri in Constellation Centauris.( The Centaur).    A Red Dwarf star 4.2 lightyears away.  1/8 Solar Mass.  40 times the density of the Sun.  Magnitude 5.5.  17% Solar Luminosity.  85% of its radiation in is infrared.  1/7 diameter of the Sun and 1.5 times the diameter of Jupiter.  129 times the mass of Jupiter.

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----------  (7)  The smallest star possible is a White Dwarf, which is a neutron star.  17% the mass of our Sun but so small because it is so dense.  Its gravity has collapsed the electrons of hydrogen into the protons forming neutrons, called electron degenerate matter.  It is the mass of the Sun but the diameter of the Earth.  6% of all known stars in our neighborhood are White Dwarfs.  They represent probably 97% of all the stars in our Galaxy.  When stars die, they burn all their fuel, no radiation exists to push back from the force of gravity.  The star collapses into the densest form of matter.  If it gets any denser it turns into a Blackhole.

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----------  (8)  The star most likely to go supernova next.  Betelgeuse in the Constellation Orion. (The Hunter).  It is the second brightest star in the Constellation of Orion, the 9th brightest in the sky.  It is a Red Supergiant only 8,500,000 years old.  But, because it is so massive it could go supernova any day now. 1,000 times Sun’s diameter.  20 times Solar Mass. And, only 640 lightyears away when it goes supernova its Gamma Ray Bursts could damage our planet.

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----------  (9)  The fastest star in the Constellation Hydra ( The Water Snake).  SDSS is traveling 1,500,000 miles per hour, which is twice the escape velocity of the Milky Way Galaxy.  It will someday fly right out of our galaxy.  Discovered in 2005 it is traveling 0.002 times the speed of light.

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----------  (10)  The first star found to have a planet is 51 Pegasus in the Constellation Pegasus. (The Winged Horse).    It is a sun like star 50.1 lightyears away.  Discovered in 1995 the planet in orbit is 5.49 Solar Mass.  The star is a yellow Dwarf star visible with binoculars.  It has planet 1/2 the size of Jupiter but orbiting only 0.052 AU with a period of 37 days.

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May 24, 2023                STARS  HAVE  NAMES             1082        4021

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--------------------- ---  Wednesday, May 24, 2023  ---------------------------------

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