Andrew Yee[_1_]
March 12th 08, 06:48 PM
Wesleyan University
Middletown, Connecticut
For more information contact:
William Herbst, Wesleyan University
860-685-3672
EMBARGOED UNTIL MARCH 12, 2008, 14:00 EST
First Observation of Earth-Like Planet Formation
For the first time, astronomers have observed the initial phase in the
formation of an earth-like planet.
The discovery, highlighted in the March 13th issue of Nature, was documented
by a team of astronomers led by William Herbst, the Van Vleck Professor of
Astronomy professor at Wesleyan, and Catrina Hamilton PhD '03, professor of
physics and astronomy at Dickenson College.
What Herbst and other astronomers on his team observed was that a
protoplanitary disk, or ring, around the binary star known as KH 15D, is
composed of solid particles larger than what is usually observed in space.
"For hundreds of years, scientists have been theorizing that Earth-like
planets form when gas and dust around a star get compressed into these disks
and the material begins to coalesce into planets. But until now we never had
the ability to study this process in detail," Herbst said. "The unique
geometry presented by KH 15D and the way the light was being reflected off
the disk allowed us to get a good look at the structure of the disk We were
amazed at what we saw."
The disk orbiting KH 15D is at least the size of Jupiter's orbit and
composed of sand-sized grains that have grown from microscopic-sized
particles to form the larger grains. These grains are now approximately 1 mm
in diameter, much larger than the tiny particles typically seen in space.
This is also the characteristic size of "chondrules," small glassy spherules
that are found in the most primitive solar system, the so-called
carbonaceous chondrite meteorites.
A Flash animation of what the team observed this can be seen here:
http://www.wesleyan.edu/newsrel/kh15d_animation.html
The observations of the disk were made over several years using some of the
largest telescopes in the world, including the 10-meter telescope of the
W.M. Keck Observatory in Hawaii. More modest telescopes, including the one
at Wesleyan University's Van Vleck observatory and the Maidanak Observatory
in Uzbekistan, were also used in the study.
Located approximately 2,400 light years from earth and also known within the
astronomical community as the "winking star," KH 15D was first documented in
1995 by Herbst and his then-graduate student Kristin Kearns. An ensuing
Ph.D. thesis by Herbst student Catrina Hamilton, now on the faculty of
Dickenson College, further solidified the importance of this star and
brought it to the attention of the astronomical community. In 2004, two
groups of astronomers on opposite coasts showed that KH 15D's winking was a
result binary star with an orbiting period of 48.36 days within a large
disk. The winking effect was generated as one of the stars alternately rose
above and set below the disk.
What Herbst, Hamilton and the rest of the team observed recently is that the
disk is slowly hiding the stars from view and putting them in a permanent
state of faintness, though still visible by the reflection off the disk.
"Because of how the light is being reflected there are opportunities to make
observations about the chemical composition of these sand-like particles,"
Herbst said. "That's very exciting because it opens up so many doors for new
type of research on this disk."
Herbst is the Chair and Van Vleck Professor of Astronomy at Wesleyan
University. The members of Herbst's team documenting the observations
include Catrina Hamilton, who received her Ph.D. degree in Physics from
Wesleyan University in 2003 with Herbst as her advisor and is now on the
faculty of Dickinson College; Katherine LeDuc, M.A.'07; Joshua N. Winn of
M.I.T.; Christopher M. Johns-Krull of Rice University; Reinhard Mundt of the
Max-Planck-Institute for Astronomy in Heidelberg, Germany; and Mansur
Ibrahimov of the Ulugh Bek Astronomical Institute in Tashkent, Uzbekistan.
Support for the work has come over the years from NASA's Origins of Solar
Systems program and from the W. M. Keck Observatory Principal Investigator's
Fund.
For additional information, go to:
https://wesfiles.wesleyan.edu/home/wherbst/web/KH15D
Middletown, Connecticut
For more information contact:
William Herbst, Wesleyan University
860-685-3672
EMBARGOED UNTIL MARCH 12, 2008, 14:00 EST
First Observation of Earth-Like Planet Formation
For the first time, astronomers have observed the initial phase in the
formation of an earth-like planet.
The discovery, highlighted in the March 13th issue of Nature, was documented
by a team of astronomers led by William Herbst, the Van Vleck Professor of
Astronomy professor at Wesleyan, and Catrina Hamilton PhD '03, professor of
physics and astronomy at Dickenson College.
What Herbst and other astronomers on his team observed was that a
protoplanitary disk, or ring, around the binary star known as KH 15D, is
composed of solid particles larger than what is usually observed in space.
"For hundreds of years, scientists have been theorizing that Earth-like
planets form when gas and dust around a star get compressed into these disks
and the material begins to coalesce into planets. But until now we never had
the ability to study this process in detail," Herbst said. "The unique
geometry presented by KH 15D and the way the light was being reflected off
the disk allowed us to get a good look at the structure of the disk We were
amazed at what we saw."
The disk orbiting KH 15D is at least the size of Jupiter's orbit and
composed of sand-sized grains that have grown from microscopic-sized
particles to form the larger grains. These grains are now approximately 1 mm
in diameter, much larger than the tiny particles typically seen in space.
This is also the characteristic size of "chondrules," small glassy spherules
that are found in the most primitive solar system, the so-called
carbonaceous chondrite meteorites.
A Flash animation of what the team observed this can be seen here:
http://www.wesleyan.edu/newsrel/kh15d_animation.html
The observations of the disk were made over several years using some of the
largest telescopes in the world, including the 10-meter telescope of the
W.M. Keck Observatory in Hawaii. More modest telescopes, including the one
at Wesleyan University's Van Vleck observatory and the Maidanak Observatory
in Uzbekistan, were also used in the study.
Located approximately 2,400 light years from earth and also known within the
astronomical community as the "winking star," KH 15D was first documented in
1995 by Herbst and his then-graduate student Kristin Kearns. An ensuing
Ph.D. thesis by Herbst student Catrina Hamilton, now on the faculty of
Dickenson College, further solidified the importance of this star and
brought it to the attention of the astronomical community. In 2004, two
groups of astronomers on opposite coasts showed that KH 15D's winking was a
result binary star with an orbiting period of 48.36 days within a large
disk. The winking effect was generated as one of the stars alternately rose
above and set below the disk.
What Herbst, Hamilton and the rest of the team observed recently is that the
disk is slowly hiding the stars from view and putting them in a permanent
state of faintness, though still visible by the reflection off the disk.
"Because of how the light is being reflected there are opportunities to make
observations about the chemical composition of these sand-like particles,"
Herbst said. "That's very exciting because it opens up so many doors for new
type of research on this disk."
Herbst is the Chair and Van Vleck Professor of Astronomy at Wesleyan
University. The members of Herbst's team documenting the observations
include Catrina Hamilton, who received her Ph.D. degree in Physics from
Wesleyan University in 2003 with Herbst as her advisor and is now on the
faculty of Dickinson College; Katherine LeDuc, M.A.'07; Joshua N. Winn of
M.I.T.; Christopher M. Johns-Krull of Rice University; Reinhard Mundt of the
Max-Planck-Institute for Astronomy in Heidelberg, Germany; and Mansur
Ibrahimov of the Ulugh Bek Astronomical Institute in Tashkent, Uzbekistan.
Support for the work has come over the years from NASA's Origins of Solar
Systems program and from the W. M. Keck Observatory Principal Investigator's
Fund.
For additional information, go to:
https://wesfiles.wesleyan.edu/home/wherbst/web/KH15D