March 14, 2012


Evidence for Planets Around the Star Vega

Before we discuss the possibilities of any planet or planets existing around the star system Vega, let’s take a look at the star itself.  The following bullets will give some perspective as to position, size, mass, temperature, luminosity, etc relative to this celestial body.

  • Vega is also know as Alpha Lyrae and is the brightest star in the Constellation Lyra.  The name itself is derived from “Wega” and is Arabic for “Swooping Eagle” (Al Nasr al Waki).  It is the lower right member of the Summer Triangle and is actually visible with the naked eye from the Northern Hemisphere.  The photograph below will show the position relative to other constellation
  • Vega is the fifth (5th) brightest star visible from Earth and the third (3rd) brightest visible from mid-northern latitudes, after Sirius and Arcturus.
  • It is 25.3 light-years from Earth and is the sixth (6th) closest of the bright start if you exclude Alpha Centauri, which is not easily visible from most of the Northern Hemispheres.
  • It has a very distinct blue color with an estimated surface temperature of 17,000 degrees F, making it about 7,000 degrees F hotter than our own Sun.
  • Vega has a diameter roughly 2.5 times greater than our Sun and is slightly less in mass.  The internal pressures and temperature make it burn much faster, thus producing thirty-five to forty times the energy of the Sun.
  • Around 500 million years old, it is already middle-age and will run out of fuel in another one-half billion years. 
  • Vega radiates between thirty-seven (37 %) and fifty-eight (58 %) percent more ultraviolet light than our Sun, demonstrating a sixty-three (63%) greater abundance of elements heavier than hydrogen.

On January 10, 2005, astronomers using the infrared Spitzer Space Telescope announced that the dust ring around Vega was much larger than previously estimated.  The disk appears to be mostly composed of very fine dust particles that were probably created from collisions of protoplanetary bodies around 90 AUs (astronomical units) from the star but blown away by its intense radiation.  On the other hand, the mass and short lifetime of these small particles indicate the disk detected was created by a large and relatively recent collision that may have involved objects as big as the planet Pluto.   The irregular shape of the disk is the clue that it likely contains planets, maybe habitable planets.  Modeling suggests that a Neptune-like planet actually formed much closer to the star than its current position.  As it moved out to its current wide orbit over 56 million years, many comets were swept out with it, causing the dust ring to become “clumpy”.  This is exactly the same process that occurred during the formation of our own solar system.  The model estimates that the “clumps” in the disk will rotate around Vega once every three hundred years.  A rendition of this ring is given as follows:

It is very conceivable that this Neptune-like planet harbors some form of life.  Intelligent life, probably not as we define the term here on Earth, but life.   The irregular shape of the disk is the clue that it is likely to contain planets explains astronomer Mark Wyatt.   Although we can’t directly observe the planets, they have created clumps in the disk of dust around the star.  Another rendition of those “bumps” may be seen below.   This is an infrared photograph of the system with the position of the suggested planet being very prominent. 

Let us now take another look.  In March 2009, NASA launched the Kepler space telescope and as a result, astronomers have spotted two small, Earth-like planets orbiting, one called Kepler-20e and the other Kepler-20f.  Kepler 20-e is 1,000 light years away and in the constellation Lyra.  The very same constellation as Vega.   A graphic of the Kepler telescope is given below:

   Planet Kepler-20e is 1.03 times the diameter of Earth and three (3%) percent larger.   Researchers believe Kepler 20e orbits its sun every six days and is a blend of silicates and iron.  Kepler 20f, which orbits its sun every 20 days, is bigger and very well could have developed an atmosphere of water vapor.     Could it be possible that the star-system Vega is rightly positioned to support some form of life—intelligent or otherwise?   It would be a significant history-making event if life could be found on another planet.  The thought that we are really not alone in the universe would be shattering to some people—maybe most people.  I do think it is imperative that we continue looking with marvelous instruments like Hubble, Kepler and deep-space probes.  I also think SETI offers some aid although the Cosmos is expansive and one has to wonder where to look.  The age-old question of “why are we here”—“where did we come from” has yet to be answered.  Maybe Dr. Sagan was correct when he stated, “We are all made from star-stuff”. 


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