Barnard’s Mirror

If you look at the patch of sky between the Belt of Orion and Sirius there is bright 1st Magnitude star.  Just there on the right edge of the constellation Monoceros.  Down from Betelguese before you reach 53 Ori.  It’s apparent magnitude is 1.15 so you can’t miss it.  Absolute magnitude is 4.85 so it’s close, 1.82 parsecs or 5.9 light years.  See it?

The Sun from Barnard's Star

Hello neighbour! So what does this star hide? Via http://www.astronexus.com

It is a G class main sequence star, G2V to be more precise, a bright white star compressing 600 million Tons of Hydrogen into Helium every second.  It has a mass of about  2×1030 kilograms, a surface temperature about 5500 °C and spectroscopy says it also contains a small but significant amount of oxygen, carbon, neon and Iron in it’s make up.

This star gets more interesting for two important observations.  The first is from a process known as Doppler Spectroscopy, a method used to detect exoplanets by looking for the tell-tale blue-red shift wobble in a star caused by an orbiting planet.  The most sensitive instruments suggest that this star is orbited by more than one planet and certainly Transit observations over a long period have hinted at two giants and potentially some smaller terrestrial planets.  The wobble is slight and the transits small but the evidence is there.

The second observation comes from radio astronomy, regular pulses of radio noise that have a regular variation of intensity.

Earth's radio signature seen from Barnard's Star

Radio Flux density orignating from Star in Monoceros. Via http://zebu.uoregon.edu/1996/ph123/l16c.html

It’s origin shifts slightly around the star over a period of several months and there appears to be a daily, repeated variation in transmission power.  A rotating planet with some sort of radio source? Undocumented natural phenomenon? A broadcasting civilisation? Its indecipherable and after a journey of 36 trillion miles is pretty weak, but does appear to be full of repeating patterns and occurs on a range of closely related frequencies.

But that is as far as observation will take us for now.  No ship or probe we send could reach there in less than several thousand years, the next generation of telescopes might reveal more about potential planets, perhaps even the chemical signatures in atmospheres that may provide further evidence of life.

But in the mean time it will have to remain an interesting Mag 1 star in Monoceros, just to the left of Orion.

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About astronomersden

Daddy, Hubby, Teacher and when ever I get the chance Astronomer.
This entry was posted in Astronomy, Exoplanets, Orion, Sun, The Astronomer's Den and tagged , , , , , , , . Bookmark the permalink.

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