[Congressional Record (Bound Edition), Volume 147 (2001), Part 2]
[Senate]
[Pages 2770-2771]
[From the U.S. Government Publishing Office, www.gpo.gov]



                     ENERGY FROM A BROWN DWARF STAR

  Mr. DOMENICI. Mr. President, I rise today to congratulate scientists 
working with the Very Large Array, VLA, astronomical radio observatory 
near Socorro, New Mexico on detecting energy from a brown dwarf star. 
For over twenty years, the VLA has provided significant scientific 
knowledge to astronomers.
  Working on a student project, scientists, graduate, and undergraduate 
students discovered the first sustained radio emission from a brown 
dwarf star, an object similar to a small star without enough mass to 
sustain nuclear fusion of hydrogen. Discovered only 5 years ago, brown 
dwarf stars were considered unable to emit persistent radio emissions. 
This finding helps astronomers study the link between large, gaseous 
planets and small stars.
  I am proud to support the VLA and the contributions being made to our 
understanding of the cosmos. I also applaud the work and efforts of the 
scientists and students involved in making this noteworthy discovery.
  I ask that the February 21, 2001, New York Times article entitled, 
``Surprise in the Heavens as Energy Is Detected in a Brown Dwarf'' be 
printed in the Record.
  The article follows:

             [From The New York Times Wed., Feb. 21, 2001]

     Surprise in the Heavens as Energy Is Detected in a Brown Dwarf

                            (By James Glanz)

       A dim, fading object wandering alone through space, 
     something between a large planet and a tiny star, turns out 
     to be roiled by storms several times more powerful than the 
     most energetic flares on the Sun, a team of radio astronomers 
     has found.
       The existence of such powerful, stormy radio emissions in 
     this kind of celestial object, a brown dwarf, is highly 
     unexpected and could shed light on the dividing line between 
     stars and planets.
       The research had been considered so unpromising that the 
     discovery was made not as part of any large-scale 
     astronomical search but an accidental find in a student 
     project at the Very Large Array a set of raido-telescopes at 
     the National Radio Astronomy Observatory near Socorro, NM.
       The students happened to have the array trained on the 
     brown dwarf when it flared. Two senior radio astronomers, Dr. 
     Dale A. Frail of the National Radio Astronomy Observatory and 
     Dr. Shrinivas Kulkarni of the California Institute of 
     Technology, then became involved in follow-up observations, 
     which were led by Edo Berger, a graduate student at Caltech.
       The follow-up observations showed that the object's 
     magnetic fields were extremely weak, another surprise, since 
     flares are normally powered by the energy in magnetic fields.
       A paper on the study has been accepted at the journal 
     Nature and was posted Monday and a Web site at the Los Alamos 
     National Laboratory where most astronomers place their new 
     work.
       The existence of brown dwarfs, which are cool, dim and 
     difficult to observe, was confirmed only five years ago by a 
     team led by Dr. Kulkarni. Thought to have masses less than 8 
     percent that of the Sun, their cores never become hot enough 
     to ignite the fusion process that allows ordinary stars to 
     shine for billions of years.
       Instead, brown dwarfs gradually cool and fade after they 
     form. Because brown dwarfs have an identity somewhere between 
     that of large, gaseous planets like Jupiter and that of the 
     smallest ordinary stars, astronomers said the new discovery 
     should illuminate the structure of a crucial link between the 
     two better-known classes of astronomical objects.
       Dr. Adam Burrows, an astrophysicist at the University of 
     Arizona, said energetic particles and waves in the magnetic 
     fields around Jupiter split out radio emissions that could be 
     detected on Earth. But Dr. Burrows said that at the distance 
     of the brown dwarf, more than a dozen light-years into deep 
     space, those emissions could never be picked up.
       ``That they do see emission from a sister object at such a 
     distance is quite amazing,'' he said.
       Ordinary stars with relatively low masses do show energetic 
     flaring, Dr. Burrows said,

[[Page 2771]]

     but their magnetic fields are also much stronger. Flares on 
     the Sun often occur when magnetic fields ``reconnect,'' or 
     suddenly snap like rubber bands after they break and then 
     splice together in new configurations. So a weak magnetic 
     field would not be expected to create strong flaring.
       Another astrophysicist, Dr. Jeffrey Linsky of the 
     University of Colorado, said those apparent mysteries might 
     carry a message about the difference between true stars and 
     brown dwarfs. The cooler cores of brown dwarfs, like a pot of 
     soup on a low flame, might create less turbulence inside the 
     dwarfs, Dr. Linsky said. That relative quiescence might 
     generate weaker magnetic fields--but possibly with 
     conformations, or geometries, that make them more likely to 
     reconnect.
       If that is the case, Dr. Linsky said, then perhaps ``the 
     geometry is very different in such a way that it produces a 
     few very large flares.''
       Dr. Lars Bildsten, an astrophysicist at the Institute for 
     Theoretical Physics at the University of California at Santa 
     Barbara, cautioned that because brown dwarfs were so 
     different from the Sun, it was hard to know what to expect 
     from them. The radio observations were at least consistent 
     with sketchy observations in other bands of the spectrum, Dr. 
     Bildsten said.
       Other scientists said they were at a loss to explain the 
     puzzling findings, whose authors include Mr. Berger, Dr. 
     Kulkarni and Dr. Frail as well as about a dozen graduate and 
     undergraduate students from places like Oberlin College in 
     Ohio, Agnes Scott College in Decatur, Ga., and New Mexico 
     State University in Las Cruces.
       ``This is a pretty amazing result,'' said Dr. Jill Knapp, a 
     Princeton astronomer. ``There seem to be some quite 
     unexpected things going on with these very cool, low-mass 
     objects.''

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