Dwarf planet Haumea shines with crystalline ice

ScienceDaily (May 13, 2011) — The fifth dwarf planet of the solar system, Haumea, and at least one of its two satellites, are covered in crystalline water-ice due to the tidal forces between them and the heat of radiogenic elements. This is the finding of an international research study using observations from the VLT telescope at the European Southern Observatory in Chile.

The tiny and strange planet Haumea moves beyond the orbit of Neptune. It has the shape of a flattened rugby ball and is around 2,000 km long. It spins completely in less than four hours, at one of the fastest rotation speeds in the solar system. The crystallised water that covers this planet and its two satellites (Hi'iaka and Namaka) makes them shine in the darkness of space.

Now an international research team has confirmed that 75% of Haumea and 100% of Hi'iaka (which is around 400 km in diameter) are covered with crystallised water-ice (with an ordered structure) and not, as would have been expected, with amorphous ice disorganised due to solar radiation. The study suggests that the planet is made up of a frozen outer layer and an internal section made up of between 88% and 97% rock (with a density of 3.5 g/cm3).

"Since solar radiation constantly destroys the crystalline structure of ice on the surface, energy sources are required to keep it organised. The two that we have taken into consideration are that able to generate radiogenic elements (potassium-40, thorium-232 and uranium-238) from the inside, and the tidal forces between Haumea and its satellites (as seen between Earth and the Moon)," Benoit Carry, co-author of the study and a researcher at the ESAC Centre of the European Space Agency (ESA) in Madrid (Spain), said.

The researcher also highlights other peculiarities of Haumea: "Its orbital plane is inclined at 28º with respect to the usual plane of planets in the solar system, the orbits of its satellites are not on the same plane either -- which is very unusual -- and the entire system belongs to a single family within the frozen objects in the Kuiper Belt (at a distance of between 4.5 billion and more than 15 billion kilometres from the Sun)."

According to the scientists, the two satellites could have been created by another object smashing into Haumea, which could also have originated the rapid rotation of the dwarf planet (3.9 hours) and have moulded it into its rugby ball shape. Some numerical models have demonstrated that this could be caused by a fairly tangential impact.

Observations from the SINFONI instrument of the Very Large Telescope (VLT), the enormous telescope of the European Southern Observatory (ESO) in Chile, were used in order to carry out the study, which has been published in the journal Astronomy & Astrophysics. ESO astronomer Christophe Dumas led this study from the observatory.

"SINFONI is an integral field spectrometer that provides 'data cubes' in which two of the dimensions are spatial (like those of any flat image), while the third is spectral, meaning that each layer of the cube is an image taken with a different wave size," explains Carry.

The mystery of Haumea

The scientist acknowledges that the precise orbits and sizes of the dwarf planet are still not known (they are operating with approximate scales of around 2,000 x 1,500 x 1,000 km) nor are those of its satellites. In reality, these are two very distant bright points of light, the data for which are obtained indirectly.

In the case of the tiny Namaka (around 200 km in diameter), the signal at the time it was observed was so weak that it was impossible to obtain information about its surface, although new data on its orbit were gathered. Meanwhile, the models for the tidal forces of this strange system are also improving.

Another of the mysteries of Haumea is the presence of a dark, reddish spot, which contrasts with the whitish colour of the planet. "My interpretation of the infrared photometry is that this area could be a richer source of crystalline water-ice than the rest of the surface," Pedro Lacerda, co-discoverer of the spot and an astronomer at Queen's University in Belfast (United Kingdom), said. The researcher does not rule out the possibility of some kind of irradiated mineral or organic matter having caused this colouration.

Haumea is the fifth dwarf planet in the solar system along with Pluto, Ceres, Eris and Makemake. Its existence was confirmed in 2005, when it was called 2003 EL61 (from the international nomenclature code: year of first observation, half and order number).

Two teams of astronomers contested the discovery. The first group was led by the Spanish researcher José Luis Ortiz Moreno from the Institute of Astrophysics of Andalusia (CSIC), while the other was led by the astrophysicist Michael E. Brown from the California Institute of Technology (Caltech, USA).

In the end, the International Astronomical Union decided to accept the discovery by the Spanish team, but named the strange dwarf planet and its satellites according to names suggested by the American team. In Hawaiian mythology, Haumea is the goddess of fertility and birth, and Hi'iaka and Namaka are two of her daughters.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Plataforma SINC, via AlphaGalileo.

Journal Reference:

C. Dumas, B. Carry, D. Hestroffer, F. Merlin. High-contrast observations of (136108) Haumea. Astronomy & Astrophysics, 2011; 528: A105 DOI: 10.1051/0004-6361/201015011

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Drive test: Super-stable laser shines in minivan experiment

ScienceDaily (May 12, 2011) — In a step toward taking the most advanced atomic clocks on the road, physicists at the National Institute of Standards and Technology (NIST) have designed and demonstrated a super-stable laser operating in a cramped, vibrating location -- a minivan.

The experiment shows how advanced lasers can be made both stable and transportable enough for field use in geodesy, hydrology, improved radar and space-based tests of fundamental physics.

The drive tests, limited to a short excursion of five meters across the grass at the NIST Boulder, Colo., campus, are described in Optics Express. Scientists evaluated the infrared fiber laser's performance with the vehicle stationary, with the motor alternately off and idling, and moving over uneven ground at speeds of less than 1 meter per second (i.e., 3.6 km/hr). The laser frequency remained stable enough with the car parked -- the most likely situation in the field -- to be used in some applications now, says David Leibrandt, a NIST post-doctoral researcher.

"Our group has been building and using ultra-stable lasers for more than 10 years, but they're large and delicate," Leibrandt explains. "The ones we use for our optical atomic clocks occupy a small room and have to be very carefully isolated from seismic and acoustic vibrations. This paper presents a new design that is less sensitive to vibrations and could be made much smaller."

NIST scientists stabilized the test laser's frequency using a common technique -- locking it to the extremely consistent length of an optical glass cavity. This sphere, about the size of a small orange, hangs in a customized mount with just the right stiffness. The scientists also designed a system to correct the laser frequency when the vehicle moves. Six accelerometers surrounding the cavity measure its linear and rotational acceleration. The accelerometers' signals are routed to a programmable computer chip that predicts and corrects the laser frequency in less than 100 microseconds.

The new laser will make it easier to use advanced atomic clocks for geodesy (measurements of Earth), an application envisioned by the same NIST research group. The laser also might be used on moving platforms, perhaps in space-based physics experiments or on Earth generating low-noise signals for radar. Study results indicate the laser is roughly 10 times more resistant to undesirable effects from vibration or acceleration than the best radio frequency crystal oscillators. Improved mechanical design and higher-bandwidth accelerometers could make the laser even more stable in the future, the researchers say.

The research is supported by the Office of Naval Research, Air Force Office of Scientific Research, and Defense Advanced Research Projects Agency.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Institute of Standards and Technology (NIST).

Journal Reference:

David R. Leibrandt, Michael J. Thorpe, James C. Bergquist, Till Rosenband. Field-test of a robust, portable, frequency-stable laser. Optics Express, 2011; 19 (11): 10278 DOI: 10.1364/OE.19.010278

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Dwarf planet Haumea shines with crystalline ice

ScienceDaily (May 13, 2011) — The fifth dwarf planet of the solar system, Haumea, and at least one of its two satellites, are covered in crystalline water-ice due to the tidal forces between them and the heat of radiogenic elements. This is the finding of an international research study using observations from the VLT telescope at the European Southern Observatory in Chile.

The tiny and strange planet Haumea moves beyond the orbit of Neptune. It has the shape of a flattened rugby ball and is around 2,000 km long. It spins completely in less than four hours, at one of the fastest rotation speeds in the solar system. The crystallised water that covers this planet and its two satellites (Hi'iaka and Namaka) makes them shine in the darkness of space.

Now an international research team has confirmed that 75% of Haumea and 100% of Hi'iaka (which is around 400 km in diameter) are covered with crystallised water-ice (with an ordered structure) and not, as would have been expected, with amorphous ice disorganised due to solar radiation. The study suggests that the planet is made up of a frozen outer layer and an internal section made up of between 88% and 97% rock (with a density of 3.5 g/cm3).

"Since solar radiation constantly destroys the crystalline structure of ice on the surface, energy sources are required to keep it organised. The two that we have taken into consideration are that able to generate radiogenic elements (potassium-40, thorium-232 and uranium-238) from the inside, and the tidal forces between Haumea and its satellites (as seen between Earth and the Moon)," Benoit Carry, co-author of the study and a researcher at the ESAC Centre of the European Space Agency (ESA) in Madrid (Spain), said.

The researcher also highlights other peculiarities of Haumea: "Its orbital plane is inclined at 28º with respect to the usual plane of planets in the solar system, the orbits of its satellites are not on the same plane either -- which is very unusual -- and the entire system belongs to a single family within the frozen objects in the Kuiper Belt (at a distance of between 4.5 billion and more than 15 billion kilometres from the Sun)."

According to the scientists, the two satellites could have been created by another object smashing into Haumea, which could also have originated the rapid rotation of the dwarf planet (3.9 hours) and have moulded it into its rugby ball shape. Some numerical models have demonstrated that this could be caused by a fairly tangential impact.

Observations from the SINFONI instrument of the Very Large Telescope (VLT), the enormous telescope of the European Southern Observatory (ESO) in Chile, were used in order to carry out the study, which has been published in the journal Astronomy & Astrophysics. ESO astronomer Christophe Dumas led this study from the observatory.

"SINFONI is an integral field spectrometer that provides 'data cubes' in which two of the dimensions are spatial (like those of any flat image), while the third is spectral, meaning that each layer of the cube is an image taken with a different wave size," explains Carry.

The mystery of Haumea

The scientist acknowledges that the precise orbits and sizes of the dwarf planet are still not known (they are operating with approximate scales of around 2,000 x 1,500 x 1,000 km) nor are those of its satellites. In reality, these are two very distant bright points of light, the data for which are obtained indirectly.

In the case of the tiny Namaka (around 200 km in diameter), the signal at the time it was observed was so weak that it was impossible to obtain information about its surface, although new data on its orbit were gathered. Meanwhile, the models for the tidal forces of this strange system are also improving.

Another of the mysteries of Haumea is the presence of a dark, reddish spot, which contrasts with the whitish colour of the planet. "My interpretation of the infrared photometry is that this area could be a richer source of crystalline water-ice than the rest of the surface," Pedro Lacerda, co-discoverer of the spot and an astronomer at Queen's University in Belfast (United Kingdom), said. The researcher does not rule out the possibility of some kind of irradiated mineral or organic matter having caused this colouration.

Haumea is the fifth dwarf planet in the solar system along with Pluto, Ceres, Eris and Makemake. Its existence was confirmed in 2005, when it was called 2003 EL61 (from the international nomenclature code: year of first observation, half and order number).

Two teams of astronomers contested the discovery. The first group was led by the Spanish researcher José Luis Ortiz Moreno from the Institute of Astrophysics of Andalusia (CSIC), while the other was led by the astrophysicist Michael E. Brown from the California Institute of Technology (Caltech, USA).

In the end, the International Astronomical Union decided to accept the discovery by the Spanish team, but named the strange dwarf planet and its satellites according to names suggested by the American team. In Hawaiian mythology, Haumea is the goddess of fertility and birth, and Hi'iaka and Namaka are two of her daughters.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Plataforma SINC, via AlphaGalileo.

Journal Reference:

C. Dumas, B. Carry, D. Hestroffer, F. Merlin. High-contrast observations of (136108) Haumea. Astronomy & Astrophysics, 2011; 528: A105 DOI: 10.1051/0004-6361/201015011

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Drive test: Super-stable laser shines in minivan experiment

ScienceDaily (May 12, 2011) — In a step toward taking the most advanced atomic clocks on the road, physicists at the National Institute of Standards and Technology (NIST) have designed and demonstrated a super-stable laser operating in a cramped, vibrating location -- a minivan.

The experiment shows how advanced lasers can be made both stable and transportable enough for field use in geodesy, hydrology, improved radar and space-based tests of fundamental physics.

The drive tests, limited to a short excursion of five meters across the grass at the NIST Boulder, Colo., campus, are described in Optics Express. Scientists evaluated the infrared fiber laser's performance with the vehicle stationary, with the motor alternately off and idling, and moving over uneven ground at speeds of less than 1 meter per second (i.e., 3.6 km/hr). The laser frequency remained stable enough with the car parked -- the most likely situation in the field -- to be used in some applications now, says David Leibrandt, a NIST post-doctoral researcher.

"Our group has been building and using ultra-stable lasers for more than 10 years, but they're large and delicate," Leibrandt explains. "The ones we use for our optical atomic clocks occupy a small room and have to be very carefully isolated from seismic and acoustic vibrations. This paper presents a new design that is less sensitive to vibrations and could be made much smaller."

NIST scientists stabilized the test laser's frequency using a common technique -- locking it to the extremely consistent length of an optical glass cavity. This sphere, about the size of a small orange, hangs in a customized mount with just the right stiffness. The scientists also designed a system to correct the laser frequency when the vehicle moves. Six accelerometers surrounding the cavity measure its linear and rotational acceleration. The accelerometers' signals are routed to a programmable computer chip that predicts and corrects the laser frequency in less than 100 microseconds.

The new laser will make it easier to use advanced atomic clocks for geodesy (measurements of Earth), an application envisioned by the same NIST research group. The laser also might be used on moving platforms, perhaps in space-based physics experiments or on Earth generating low-noise signals for radar. Study results indicate the laser is roughly 10 times more resistant to undesirable effects from vibration or acceleration than the best radio frequency crystal oscillators. Improved mechanical design and higher-bandwidth accelerometers could make the laser even more stable in the future, the researchers say.

The research is supported by the Office of Naval Research, Air Force Office of Scientific Research, and Defense Advanced Research Projects Agency.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Institute of Standards and Technology (NIST).

Journal Reference:

David R. Leibrandt, Michael J. Thorpe, James C. Bergquist, Till Rosenband. Field-test of a robust, portable, frequency-stable laser. Optics Express, 2011; 19 (11): 10278 DOI: 10.1364/OE.19.010278

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here