Flipside of the Sun

SpaceScience.com; Feb. 15, 2001; NASA Science News: "The Sun Does a Flip"

X-ray Sun and sunspot numbers -- NASA

Spectrographs at the National Solar Observatory on Kitt Peak have detected a sudden flip in the orientation of the Sun's magnetic field.  Just a few months ago our star's northern hemisphere was home to its north magnetic pole.  Now it hosts the south pole!  Is this a sign of impending doom?  No, but it's a sure sign that solar maximum has arrived.

"This always happens around the time of solar maximum," says solar physicist David Hathaway. "The magnetic poles exchange places at the peak of the sunspot cycle. In fact, it's a good indication that Solar Max is really here."  Like clockwork the magnetic pole flip happens at the peak of every 11-year sunspot cycle; the north magnetic pole is expected to revert back to the northern hemisphere in 2012.  These field changes are felt throughout the solar system because the magnetic field of the Sun forms a bubble called the heliosphere that extends beyond the orbit of Pluto.

This year solar astronomers will have the best seat in the solar system to study the magnetic flip --  courtesy of the Ulysses spacecraft.  A joint venture of the European Space Agency and NASA, Ulysses flies 2.2 AU over the Sun's poles every six years.  In 1994 and 1996 the spacecraft made important discoveries as it swung by the solar poles during the sunspot minimum.  Having just swung by the south pole of the Sun, the craft will observe the north polar region this fall.  With those observations completed the craft will have gathered data over the course of a full solar cycle. 

Donut in the Forest 

NASA-GSFC; Feb. 22, 2001; Press Release: "Dusty Space Donut Caught with Surprise Companion"

LkHa101's donut

The old saying about not being able to see the forest because of the trees holds true in astronomy.  If you could selectively eliminate most of the trees you'd be able to detect objects hidden in the forest.  To this end astronomers have attached an interferometer aperture mask on the 10-m Keck telescope's secondary mirror that blocks 90% of the light collected.  Interference patterns made through the mask are recorded by the Near Infrared Camera and computer processed to construct an image with four times greater resolution, for small fields of view, than the Hubble Space Telescope. 

When this setup was aimed at a massive (5x size of our Sun) young (1-million years old) star called LkHa101 (522 light-years away in Perseus) astronomers saw details in the cloud of material surrounding the star and a companion star orbiting 2.6 billion miles away.  The circular cloud appears about 10 AU in diameter in the computer images, but cooler dust that does not glow in the spectral range of the camera makes the physical cloud larger.  At the center of the cloud the heat from LkHa101 burns off the in-falling material and creates a "donut hole" of radius 316-million miles around the star.  

LkHa101 and companion

Prior to the use of the interferometer aperture mask the companion star and central hole were undetectable.  "We've seen the donut hole for the first time, and it's a lot bigger than people thought," said NASA Goddard's Dr. William Danchi.  Dr. John Monnier of the Harvard-Smithsonian Center for Astrophysics adds: "These images allow us to look back in time to understand better the origins of our Sun and Solar system."  The donut of material around the star would be expected to form planets -- though LkHa101's expected life-span is only 100-million years.  Currently the star burns energy at a rate that would make it 40,000 brighter than our Sun at the same distance. 

Dr. Peter Tuthill of Sydney University in Australia makes it clear that this is only the first step in clearing the forests: "The interferometer technology demonstrated by our aperture mask lets us detect extraordinarily fine detail, and is a first step in projects that will combine light from an array of telescopes to image planets around distant stars." 

Dr. Tuthill is the primary author of a paper published in the February 22 issue of Nature that describes the findings concerning LkHa101.  Drs. Danchi and Monnier are co-authors of the study.

Image Credits: National Science Foundation, NASA and Harvard-Smithsonian Center for Astrophysics

Life Recipe Ingredients Found in France

SpaceDaily.com; Feb. 27, 2001; TerraDaily: "Meteorite Analysis Suggests Comets Delivered Life's Key Ingredients" 

France, with its passion for combining ingredients in pursuit of the perfect recipe, is also the home of a cometary meteorite containing the amino acid ingredients for the recipe of life on Earth.  Though the 1864 Orgueil meteorite, named after the town near the landing site, had previously been studied, Scripps Institute of Oceanography (San Diego) scientists re-examined it using state-of-the-art instruments to search for amino acids -- fundamental protein components required for life. 

"We found that the amino acids in Orgueil are abiotic. They were formed without the help of biology, only chemical reactions." 

-- Oliver Botta of the Scripps Institute

A fresh piece of the interior of the meteorite contained a simple mixture of amino acids.  The carbon isotope ratio in the sample indicated that the chemicals were not the result of contamination on the ground.  "We found that the amino acids in Orgueil are abiotic. They were formed without the help of biology, only chemical reactions," said Oliver Botta of the Scripps Institute. "We think these amino acids were synthesized in space."  

Scientists had previously believed that a large variety of amino acids were required to form life, but recent research indicates only a few different types of these chemicals are required for life to arise.  The amino acids in the meteorite may have been of the type that helped generate life on Earth.  So the question remained: from what type of body did the meteorite originate from?