Medium sized Kuiper belt object less dense than water

Observations of the 2002 UX25 system with HST/HRC and Keck LGS-AO/NIRC2. 

The northward orientation arrow is 0.25 arcseconds long, for scale. 

In the first column, we show the image of both 2002 UX25 and its satellite. 

Credit: arXiv:1311.0553 

Michael Brown, a planetary scientist with California Institute of Technology, has found a medium sized object in the Kuiper belt (dubbed 2002 UX25) that doesn't appear to conform to theories of how such objects came to exist.

Michael Brown

In his paper to be published in Astrophysical Journal Letters, Brown notes that the mid-sized object appears to be less dense than it should be if it followed conventional thinking that suggests the larger the objects are in the belt, the more dense they should get.

The Kuiper belt, is of course, a group of rock-like objects (comets, dwarf planets, etc.) orbiting the sun that lie farther out than Neptune.

Such Kuiper belt objects (KBOs) are believed to have formed in ways similar to the way planets did, i.e. due to accretion of material over time.

Conventional theory suggests that small KBOs are less dense than water because of their porous nature—large KBOs grew more dense as they grew larger due to gravity causing them to compact.

If the theory is correct medium size KBOs should have medium density. But this new KBO that Brown has found doesn't conform to the theory at all, instead, its density is roughly the same as smaller KBOs, suggesting that it's not size that determines KBO density, but something else. And right now, Brown notes, nobody knows what that something else might be.

12 minute exposure of dwarf planet candidate (55637) 2002 UX25 with a 24" telescope.

2002 UX25 has a diameter of roughly 650 kilometers, putting it squarely in the mid-size KBO category, and it, like other KBOs, is believed to exist in very nearly the same state it's held since the formation of the solar system.

It's in studying such objects that scientists learn more about how everything in our solar system came to be the way it is.

Until now, most scientists agreed that KBOs of a size smaller than 350 kilometers across had a density less than that of water, whereas bigger ones had a greater density.

That theory might have to be changed however as 2002 UX25 is the first medium sized KBO to have its density measured and it clearly doesn't conform.

The discovery of 2002 UX25's density properties has already led to new theories, Brown notes, with some suggesting that scientists have been wrong to assume that KBOs and the planets formed at the same time.

Instead, they suggest, that it's possible that KBOs came first and afterwards as the planets were forming, eddies formed causing KBOs to knock into one another breaking them into different sized pieces.

More information: The density of mid-sized Kuiper belt object 2002 UX25 and the formation of the dwarf planets, arxiv.org/abs/1311.0553

NASA Cassini, Keck and ESO VLT Collaborative Observation of Saturn's Aurora

Composite image of Saturn shows the entire planet, including the rings as seen by NASA's Cassini spacecraft from the south. 

The green glow represents aurora lights.

CREDIT: NASA/JPL/University of Leicester/University of Arizona

Astronomers using an observatory in Hawaii kicked off a month-long campaign to study the northern lights on Saturn study Sunday (April 21) in a live webcast from Hawaii's iconic Keck Observatory.

During a three-hour webcast, scientists discussed everything from the ringed planet's atmosphere to new discoveries made about the gas giant in the last year.

While speaking with the public via social media, the researchers also used the Keck Observatory to observe auroras on Saturn to understand how the mysterious phenomenon works.

The scientists weren't able to show live-video of the observations, but they did review some major Saturn discoveries during the webcast.

Tom Stallard

"Up until now, it's like we have been looking at the aurora in black and white — and now we're trying to look in color," Tom Stallard, an astronomer at the University of Leicester who participated in the observations yesterday, said in a statement.

"We're hoping to get much more depth to the observations we have taken — filling in a far more complete picture of the aurora as a whole, rather than disconnected parts."

The month-long campaign organized by astronomers from the University of Leicester in the U.K. brings together an international group of observers using the Cassini spacecraft in orbit around Saturn, the Hubble space telescope and the European Southern Observatory's (ESO) Very Large Telescope (VLT) in Chile.

Over the course of the next month, scientists will take observations of the ringed beauty to understand its northern lights.

University Astronomers Discover Rare Rectangular Galaxy

An international team of astronomers from the Swinburne University of Technology has discovered a rare rectangular galaxy with a striking resemblance to a cut diamond.

The galaxy is located within a group of 250 galaxies which is about 70 million light years away from earth. This unique galaxy was discovered with the giant Keck Telescope in Hawaii.

Astronomers also found that the galaxy is spinning rapidly. The outermost measured edge of this galactic disc is rotating at a speed in excess of 100,000 kilometres per hour.

"In the universe around us, most galaxies exist in one of three forms: spheroidal, disc-like, or lumpy and irregular in appearance," said Associate Professor Alister Graham from Swinburne University of Technology, in a statement.

Researchers believe that this galaxy could be formed out of the collision of two spiral galaxies.

Astronomers had earlier suspect that this galaxy was short cylinder sized galaxy; now after analysing it very keenly they found the rare rectangular shaped galaxy.

"Curiously, if the orientation was just right, when our own disc-shaped galaxy collides with the disc-shaped Andromeda galaxy about three billion years from now we may find ourselves the inhabitants of a square looking galaxy," said Professor Graham.

Most Distant Dwarf Galaxy Detected

The gravitational lens B1938+666 as seen in the infrared when observed with the 10-meter Keck II telescope with Adaptive Optics on Mauna Kea, Hawaii.

In the center is a massive red galaxy 9.8 billion light-years from Earth that acts like a cosmic magnifying glass, distorting the light from an even more distant galaxy, 17.3 billion light-years away.

The result is a spectacular Einstein ring image of the background galaxy.

The team used distortions within the ring to find evidence for a low-mass dark galaxy, which is a satellite of the foreground lensing galaxy.

Using this gravitational lensing effect the mass of the dark galaxy was found to be 200 million times the mass of the Sun, which is similar to the masses of the satellite galaxies found around our own Milky Way, but is 9.8 billion light-years further away. Credit: D. Lagattuta / W. M. Keck Observatory.

ESA: ESO's Extremely Large Telscope (E-ELT) Funding Approved

Construction of the world's largest telescope, the European Extremely Large Telescope (E-ELT), will finally push through with the approval of the funding for the project, according to the European Southern Observatory (ESO.

A joint collaboration between 15 countries, the telescope which will be built in Chile, will be the world's largest ground-based optical telescope.

ESO officials said preparatory work will soon begin at the planned site of the E-ELT at the Cerro Armazones mountain in the central part of Chile's Atacama Desert.

The ESO chose the location because of the optimal weather conditions, such as clear skies and around 320 nights of the year, in the area.

The E-ELT's primary mirror will be a staggering 138 feet (42 meters) wide, bigger that the Keck Observatory in Hawaii which has a mirror that measures 33 feet (10 meters) wide, and the Subaru telescope, also in Hawaii, that has 27 feet (8.2 m) wide.

The approved 2012 budget includes funding for initial work on the E-ELT project, such as the development of access roads to the telescope site and early construction efforts on one of the telescope's five mirrors which are expected to begin in early 2012, ESO officials said in a statement.

"The E-ELT is starting to become reality," ESO Director General Tim de Zeeuw said. "However, with a project of this size it is expected that approval of the extra expenditure will take time. Council at the same time recognizes that preparatory work must start now in order for the project to be ready for a full start of construction in 2012."

The ESO governing body is expected to make a final approval decision for the entire E-ELT project in mid-2012, with the world's largest telescope finally operational early in the next decade, ESO officials said.

ESO already has three observatories in Chile, including the Paranal Observatory, which houses the Very Large Telescope, and the La Silla Observatory, which hosts the New Technology Telescope.

Hawaii Astronomers Find Planet in the Process of Forming

Artist's conception of the area near the planet LkCa 15 b. Click on picture for larger view. Credit: Karen L. Teramura, UH IfA.

The first direct image of a planet in the process of forming around its star has been captured by University of Hawaii astronomer Adam Kraus.

What astronomers are calling LkCa 15 b, looks like a hot "protoplanet" surrounded by a swath of cooler dust and gas, which is falling into the still-forming planet.

Images have revealed that the forming planet sits inside a wide gap between the young parent star and an outer disk of dust.

Kraus (UH Institute for Astronomy) and colleague Michael Ireland (Macquarie University and the Australian Astronomical Observatory) combined the power of the 10-meter Keck Observatory telescopes with a bit of optical sleight of hand.

"LkCa 15 b is the youngest planet ever found, about 5 times younger than the previous record holder," said Kraus.

"This young gas giant is being built out of the dust and gas. In the past, you couldn't measure this kind of phenomenon because it's happening so close to the star. But, for the first time, we've been able to directly measure the planet itself as well as the dusty matter around it."

Kraus will be presenting the discovery at an Oct. 19 meeting at NASA's Goddard Space Flight Center. The meeting follows the acceptance of a research paper on the discovery by Kraus and Ireland by The Astrophysical Journal.

The optical sleight of hand used by the astronomers is to combine the power of Keck's Adaptive Optics with a technique called aperture mask interferometry. The former is the use of a deformable mirror to rapidly correct for atmospheric distortions of starlight.

The latter involves placing a small mask with several holes in the path of the light collected and concentrated by a giant telescope. With that, the scientists can manipulate the light waves.

"It's like we have an array of small mirrors," said Kraus. "We can manipulate the light and cancel out distortions." The technique allows the astronomers to cancel out the bright light of stars. They can then resolve disks of dust around stars and see gaps in the dusty layers where protoplanets may be hiding.

"Interferometry has actually been around since the 1800s, but through the use of adaptive optics has only been able to reach nearby young suns for about the last 7 years." said Dr. Ireland.

"Since then we've been trying to push the technique to its limits using the biggest telescopes in the world, especially Keck."

The discovery of LkCa 15 b began as a survey of 150 young dusty stars in star-forming regions. That led to the more concentrated study of a dozen stars.

"LkCa 15 was only our second target, and we immediately knew we were seeing something new," said Kraus. "We could see a faint point source near the star, so thinking it might be a Jupiter-like planet we went back a year later to get more data."

NASA Hubble finds Jupiter's hidden Stripe

New Hubble images reveal what happened to one of Jupiter’s main cloud belts: It’s hiding behind ammonia clouds.

“Weather forecast for Jupiter’s Southern Equatorial Belt: cloudy with a chance of ammonia,” planetary scientist Heidi Hammel of the Space Science Institute in Boulder, Colorado said in a press release Wednesday.

The gas giant’s characteristic band of dark clouds started fading late last year and had vanished completely by early May, 2010.

Images taken with Hubble’s Wide Field Camera 3 on June 7 — just over three days after an unknown object smacked into the planet — found a layer of white ammonia ice crystal clouds. The ammonia clouds float at a higher altitude than the missing brown clouds, obscuring them from view.

The images show a preview of what’s to come for the dark stripe, too. A chain of dark spots along the boundary of Jupiter’s south tropical zone peek through the white cloud layer as the ammonia thins and dissipates.

“The Hubble images tell us these spots are holes resulting from localized downdrafts. We often see these types of holes when a change is about to occur,” said planetary scientist Amy Simon-Miller of NASA.

The clouds blocking the famous equatorial stripe should clear out similarly in a couple of months, the team predicts.

“The Southern Equatorial Belt last faded in the early 1970s. We haven’t been able to study this phenomenon at this level of detail before,” Simon-Miller added. “The changes of the last few years are adding to an extraordinary database on dramatic cloud changes on Jupiter.”



The images also provided clues to the identity of the mystery object that hit Jupiter on June 3.

A lack of dark debris at the impact site, which would have been kicked up by the object exploding beneath the clouds, suggests that the object was relatively small and burned up in Jupiter’s atmosphere like a meteor.

“Hubble was only one of several observatories that looked for signs of Jupiter’s impact scar, with more results on their way,” planetary scientist Leigh Fletcher of the University of Oxford noted on Twitter. “Gemini, Keck, VLT and IRTF were all racing to find signs of the impact within hours of the event taking place.”