Tuesday, June 08, 2004

Sibling of the Sun

Sibling of the Sun
by Dave Adalian

The Sun once had a big sister.

Sol’s sibling is long dead, but as it went it may have given Earth the gift of life.

According to evidence presented at Arizona State, the Sun and its satellites were born in a shock wave caused by radiation from a huge star.

When that giant sun sparked to life 4.6 billion years or so ago, intense ultraviolet light poured into the nebula surrounding it, compressing and ionizing its gas until smaller stars formed.

Radiation from the Sun’s giant relative blasted away anything that couldn’t withstand its force, leaving just the Sun and the proto-planetary disk from which our world and the rest of the Solar System eventually formed.

Huge stars burn bright and live short lives. Sol’s older and much bigger sister’s life came to a relatively quick end in a supernova, scouring surrounding star systems with heavy elements formed by the pressure of the explosion.

Some of these elements were necessary for life. Others were radioactive, and the ASU researchers think the heat could have been responsible for the amount of water on Earth today. Also, the way Sol’s sibling exploded and its distance effected the type of planets that eventually formed.

The stars born in the stellar nursery with Sol drifted apart until today our closest neighbor is 4.2 light years away; and it may not be related at all.

This amazing and beautiful process of star formation is pictured in the famous Hubble Space Telescope image of the “Pillars of God” in the Eagle Nebula.

You don’t need to rely on the Hubble to see these magnificent deep space stellar nurseries. A host of them, including the Eagle, are visible in the area in and around Sagittarius.

In late spring and early summer, Sagittarius rises in the southeast an hour or two after sunset, following the familiar hooking shape of Scorpius.

A few of the stars of Sagittarius form the Teapot, and the only easy naked-eye nebula, the Lagoon, sits directly above it. It can be found from a dark spot amid the star clouds of the Milky Way.

Binoculars will reveal several others, including the Eagle, the Trifid and the Omega nebulas, along with a host of star clusters and fields. The area is one of the most beautiful in the sky for small optics.

Telescopes best show these delicate star-forming regions, revealing detail not otherwise available.


This column originally appeared in the Visalia (Calif.) Times-Delta on June 8, 2004.