A Star is Doomed -- Earth-type Planet Formation to Benefit?
Cosmiverse;
Jul 25, 2000; Space News: "Bomb
Waits in Space for Study”
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| Type Ia Supernovae 1994D, at lower left, outshines most of NGC 4526 -- its host galaxy. |
Many light-years from our planet, in the star system known as KPD1930+2752, a dense white dwarf star is orbited by a hot companion star in the incredibly short period of 137-minutes. The dynamics of this unusual system is dissipating energy via gravity waves -- drawing the stars closer together. These dynamics have sealed the fate of star system KPD1930+2752 -- it is doomed. University of Southampton astronomers believe the stars will collide within 200-million years from now and cause a Type Ia Supernovae. The explosion, visible across the galaxy, will spew debris that includes heavy metals across space. Fatality for such star systems have are an upshot for Earth-like planets: scientists believe that almost all the iron found on Earth originated in similar explosions. Study of this system and detection of such Type Ia Supernovae in other galaxies will help us understand the past and future of the Universe.
Asteroid Hunters Issue Report: Earth Doomed?
Cornell University; Jun 25, 2000; Press Release: "Map shows 900 asteroids that could threaten Earth"
A new study of the threat posed by Near Earth Asteroids (NEA), funded by NASA and the European Space Agency, indicates the likely orbits of the estimated 900 asteroids, one kilometer or larger, that cross the Earth's orbit. "One kilometer (about .6 of a mile) in size is thought to be a magic number, because it has been estimated that these asteroids are capable of wreaking global devastation if they hit the Earth," states William Bottke ( Cornell University) the lead researcher of the U.S.-French team that did the study. Their report, "Understanding the Distribution of Near-Earth Asteroids," is published in the June 23rd issue of the journal Science. |
| Possible NEA defense. |
According to the Cornell University press release, the " study portrays the paths of asteroids in the inner solar system as a vast Los Angeles-style traffic system crisscrossed with superhighways along which are hurtling huge, rocky projectiles. And in the middle of the highway network, on a possible collision path, is the planet Earth."
Evidence suggests that the NEA originated as a result of collisions between asteroids in the main asteroid "belt" between Mars and Jupiter. Momentum from impact and gravitational effects from the planets can divert some of these objects to cross the Earth's orbit.
Because of the difficulty in searching all areas of the sky for NEA, statistical techniques were applied to the known NEA database to arrive at the 900-count number. The orbits of known Earth-crossers were the basis of theoretical models used to indicate the likely paths that currently undetected asteroids would take to reach Earth orbit. As a result of the study, researches may have an easier time discovering the 60% of NEA that have yet to be observed.
Planet Hunters: Nearby Star Has Planet(s?)
University of Texas McDonald Observatory; Aug 7,2000; Press Release: "Search for Extrasolar Planets Hits Home"
Of the recent spate of planets found orbiting other stars, the discovery of a Jupiter class planet in the Epsilon Eridani system is most exciting. Only 10.5 light-years away, it is the closest system to Earth known to have planets. Dr. William Cochran, a member of the discovery team at the University of Texas McDonald Observatory said: "Detecting a planet orbiting Epsilon Eridani, a star very similar to our own Sun and only 3.22 parsecs from Earth, is like finding a planet in our own backyard -- relatively speaking."The planet has an estimated mass of 0.8 to 1.6 that of Jupiter and orbits at 3.2 AU from Epsilon Eridani. In our solar system that would be the distance from the Sun to the asteroid belt. Similarities with our system stop there because the new plant's seven year orbital path is highly non-circular. Epsilon Eridani itself is a young star -- only 1-billion years old -- that is slightly smaller and cooler than our sun.
The planet was detected by studying nearly 20- years of spectrophotometric data for the star. The slightly varying Doppler-shift in the high-precision measurements indicated a "wobble" in the star's motion. After ruling out other possibilities, the team decided that only a planetary body orbiting the star could be the cause.
Especially exciting is the possibility of direct imaging and measurements of the planet using large telescopes. This is possible because of the relative proximity of the star system, the planet's separation from the star and the large perturbation in the star's motion caused by the planet.
If that wasn't enough, the press release raised the real possibility of more planets in that system. Studies indicate that a dust ring comprised of 1-mm particles extend 60 AU from the system. The asymmetric shape of the ring may be due to a planet orbiting inside the ring at 30 AU. Stay tuned!
Allen Hunts for Aliens -- Nearby Stars Targeted
Reuters Newswire; Aug 1, 2000: "Telescope to Boost Hunt for Alien Life"
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| Where's Bill? |
What a difference $11.5-million makes. That's how much money Microsoft co-founder Paul Allen kicked in toward a $26-million array of radio telescopes that will scan the skies for alien life. Now named after him, the " Allen Telescope Array" will consist of hundreds of radio telescopes aligned in a grid. The project is sponsored by the SETI Institute and will be situated 290-miles north of San Francisco, at the University of California-Berkeley Hat Creek Observatory.
The SETI Institute currently spends $4-million a year to rent time on various radio telescopes. Having its own research facility is a watershed event for the non-profit organization. SETI's Jill Tarter, director of research, said, "We're overjoyed, and we're ready to move ahead.''
The first targets to be examined will be nearby stars that resemble our Sun. Traditional radio telescope research into such topics as interstellar chemistry, the structure of galactic magnetic fields and the physics of rotating neutron stars will also benefit from the telescope array. The project is expected to be completed in 2005.