Tag: Kuiper Belt

New Horizons looks back at Pluto

10:38 pm

One year after New Horizons’ breath-taking fly-by of Pluto, the science team has written a review of what they have learned.

They list what they consider the mission’s top ten discoveries, which I think can be summed up in one phrase: the uncertainty of science. Pluto was more active geologically and atmospherically than predicted by all models. It was also more complex. Other surprises: Both Pluto and Charon show evidence of sub-surface liquid oceans of water. Charon’s dark red polar baffles them. They unexpectedly found no additional moons, and also discovered that as far as they can tell by the available data, the moons were all formed when Pluto formed, something they also did not expect.

The one thing that I expected that did happen? We got close, and discovered things we had not expected. Be prepared for further surprises when New Horizons flies past Kuiper Belt object 2014 MU69 on January 1, 2019.

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A Kuiper belt object turns out to be large

5:44 pm

New observations of Kuiper Belt object 2007 OR10 have found it to be the largest unnamed object in the solar system, 955 miles across and about two-thirds the diameter of Pluto.

It also appears to rotate slowly, with each day about 45 hours long.

These results are decidedly uncertain, so don’t put much money on them. Nonetheless, the data continues to suggest that there are a lot of objects out there beyond Pluto.

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Hubble discovers moon circling Kuiper belt object

10:10 am

Worlds without end: Hubble has spotted a small moon orbiting the distant Kuiper Belt object Makemake.

The moon — provisionally designated S/2015 (136472) 1 and nicknamed MK 2 — is more than 1,300 times fainter than Makemake. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diameter is estimated to be 100 miles across. Makemake is 870 miles wide. The dwarf planet, discovered in 2005, is named for a creation deity of the Rapa Nui people of Easter Island.

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New Horizons’ future research goals

9:15 am

On Monday at a planetary science conference Alan Stern, the project scientist for New Horizons, outlined the science goals in studying the Kuiper Belt should the spacecraft’s mission be extened through 2021.

The main goal will be the January 1, 2019 fly-by of Kuiper Belt object 2014 MU69, estimated to be between 12 to 24 miles across. However, the proposal also includes the following:

“In addition to making a close flyby of MU69, we’re also going to be close enough in range to study quite a number of other small KBOs, and some large ones that are on the Pluto scale,” Stern said. New Horizons will be able to study them in ways that could never be accomplished from Earth. The closeness of the spacecraft will enable high resolution observations, and the ability to look for satellites that cannot be seen from Earth observatories or with the Hubble Telescope.

“Because we are looking back on the rest of the solar system, at the Kuiper Belt and the Centaur Population,” Stern said, “we’re going to be able to study another 18 or 20 small bodies to determine whether or not the recently discovered rings around the centaur Chariklo are a common occurrence, or something anomalous. And I don’t know of any other way over the next several years, except through New Horizons, that we can develop a data set like that.”

What I find amazing is that it appears from Stern’s remarks that NASA has not yet approved this proposal. Before the team discovered 2014 MU69, I would have been more skeptical about extending the mission, but since they will be able to do a close fly-by of a type of object never before seen, and considering the time and cost it takes to get to the Kuiper Belt, it seems foolish now to not approve this mission extension.

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Astronomers propose Neptune-sized planet in Kuiper Belt

9:13 am

The uncertainty of science: Using the orbital data of many recently discovered Kuiper Belt objects [KBOs], two astronomers have proposed the existence of a planet ten times the mass of the Earth and orbiting the sun every 20,000 years.

Trujillo and Sheppard had noted that Sedna, VP113, and several other KBOs all shared a peculiar property: their closest approach to the Sun lay in the plane of the Solar System, and they all moved from south to north when crossing that plane. Batygin and Brown analyzed the orbits further and discovered that their long axes were physically aligned, too, as if something had nudged them to occupy the same region of space around the Sun. The team concluded that a massive object must be shepherding the objects. “We have a gravitational signature of a giant planet in the outer Solar System,” Batygin says.

Planet Nine — informally known as Phattie — is probably smaller than Neptune and icy with a gassy outer layer. The gravitational effect of Uranus and Neptune would have flung it outward in the first 3 million years of the Solar System’s existence, Batygin says.

Be warned! The existence of this as-yet unseen giant planet is quite uncertain. The orbits of the KBOs they are using to postulate its existence have only been observed for a very short period and have not been completely mapped. Thus, those orbits themselves are very uncertain. Moreover, we so far have a very incomplete census of the Kuiper Belt. The orbital behavior used as evidence of another planet could also be caused by many other known factors that have not yet been observed.

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New Horizons team picks its next Kuiper Belt target

3:07 pm

The New Horizons science team has picked its next Kuiper Belt fly-by target beyond Pluto.

New Horizons will perform a series of four maneuvers in late October and early November to set its course toward 2014 MU69 – nicknamed “PT1” (for “Potential Target 1”) – which it expects to reach on January 1, 2019. Any delays from those dates would cost precious fuel and add mission risk. “2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”

The press release includes some silly gobbly-gook about how the science team can’t announce this as its official target because they still have to write up a proposal to submit to NASA, which then must ponder their decision and decree it valid. We all know this is ridiculous. Will NASA sit and ponder and make them miss their target? I doubt it.

The fly-by itself will be really exciting, because this object will truly be the most unusual we will have ever gotten a close look at, as it has spent its entire existence far out in the dim reaches of the solar system.

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The size of Pluto pinned down

12:59 pm

Data from New Horizons has allowed scientists to more firmly determine, for the first time, Pluto’s precise size.

Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were used to make this determination. This result confirms what was already suspected: Pluto is larger than all other known solar system objects beyond the orbit of Neptune. “The size of Pluto has been debated since its discovery in 1930. We are excited to finally lay this question to rest,” said mission scientist Bill McKinnon, Washington University, St. Louis.

Pluto’s newly estimated size means that its density is slightly lower than previously thought, and the fraction of ice in its interior is slightly higher. Also, the lowest layer of Pluto’s atmosphere, called the troposphere, is shallower than previously believed.

This means that Pluto is at this moment the largest Kuiper Belt object so far known, bigger than Eris, the Kuiper Belt planet discovered in 2005 that had been thought to be bigger than Pluto and whose existence was used by some to demote Pluto’s status as a planet.

I say, they are both planets, because they are both heavy enough for gravity to have forced them to become spherical.

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A solar system like our own, but when it was a baby

9:28 am

Astronomers have discovered a very young 15 million year old star only 360 light years away that has a debris disk about the size of our solar system’s Kuiper Belt.

The ring is about the same distance from its parent star as the Kuiper belt is from the Sun, and receives roughly the same amount of light. Its blue-grey colour hints that it could consist of ices and rocky silicates such as those found in the Kuiper belt, says lead author Thayne Currie, an astronomer at the Subaru Telescope in Hawaii, which is run by the National Astronomical Observatory of Japan. “This is absolutely the closest example we have of a young Kuiper belt,” he says.

The best part of this discovery however might be how it was made, by using a new instrument on the ground-based Gemini telescope on Mauna Kea in Hawaii.

The instrument, which is part of the Gemini South telescope in Chile, uses a disk called a coronagraph to blot out the glare of bright stars. That allows it to take multi-wavelength pictures of faint, orbiting planets and debris disks around stars, by recording near-infrared light from the parent star as it scatters off the debris. The researchers discovered the disk around HD 115600 fewer than 6 months after the GPI began operation. A similar instrument, known as SPHERE, began operating in May 2014 on the European Southern Observatory’s Very Large Telescope in Chile and has also begun to make discoveries.

Assuming protesters don’t force Gemini to close, we should be getting a lot more exoplanetary discoveries from it in the coming years.

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Three potential post-Pluto targets for New Horizons

9:01 am

After completing a deep search using the Hubble Space Telescope, scientists have identified three Kuiper Belt Objects (KBO) that New Horizons can actually reach after it flies past Pluto next year.

The KBOs Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the size of Pluto. Unlike asteroids, KBOs have not been heated by the sun and are thought to represent a pristine, well preserved deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago. The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto.

I think it remarkable that in the vastness beyond Pluto they were able to find any objects that also happen to be within the narrow path that New Horizons must fly after it passes Pluto in July.

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Nothing for New Horizons after Pluto

8:57 am

As New Horizons begins its final shake-down in advance of its July 2015 flyby of Pluto, scientists have so far failed to find any Kuiper Belt objects in the right place for it to fly past after Pluto.

They haven’t given up hope, however. The search continues. As for the Pluto flyby,

The hibernating spacecraft will send weekly status beacons back to Earth, with wakeup scheduled for Dec. 7 to begin the final phase of its approach to Pluto. New Horizons will stay awake for two years to prepare for the encounter, fly by Pluto, and downlink science data. The craft’s appointment with Pluto is set for July 14, 2015, when it will zoom about 6,200 miles from the icy world’s unmapped surface for a one-shot chance to explore Pluto’s geology and atmosphere.

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Hubble to search for Kuiper Belt targets for New Horizons

12:12 pm

After completing a preliminary search for potential Kuiper Belt objects which the Pluto probe New Horizons might visit, scientists have decided to use the space telescope for a deeper more complete search.

As a first step, Hubble found two KBOs drifting against the starry background. They may or may not be the ideal target for New Horizons. Nevertheless, the observation is proof of concept that Hubble can go forward with an approved deeper KBO search, covering an area of sky roughly the angular size of the full Moon. The exceedingly challenging observation amounted to finding something no bigger than Manhattan Island, and charcoal black, located 4 billion miles away.

More here.

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The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

5:52 pm

The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

This allocation is still contingent upon a test observation to see if Hubble will be able to spot enough objects to make the long observations worthwhile.

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Designed and funded on the premise that it would fly past a Kuiper belt asteroid after it flew past Pluto, the New Horizons team has so far failed to find such an asteroid and is running out of time.

9:29 am

Designed and funded on the premise that it would fly past a Kuiper belt object (KBO) after it flew past Pluto, the New Horizons team has so far failed to find such an asteroid and is running out of time.

In theory, project scientists should have identified a suitable KBO long ago. But they postponed their main search until 2011, waiting for all the possible KBO targets to begin converging on a narrow cone of space that New Horizons should be able to reach after its Pluto encounter. Starting to look for them before 2011 would have been impossible, says Grundy, because they would have been spread over too much of the sky.

Now that the hunt for KBOs is on, the New Horizons researchers have mainly been using the 8.2-metre Subaru Telescope in Hawaii and the 6.5-metre Magellan Telescopes in Chile. They have found about 50 new KBOs; none is close enough for New Horizons to reach.

I always thought it unlikely that they would be able to, on the fly, find a suitable candidate that New Horizons could reach in the very empty vastness beyond Pluto. In fact, it seemed absurd and to me seemed instead a transparent public relations ploy to get the funding for the fly-by mission to Pluto. Sadly, my cynical perspective here appears to be turning out to be true.

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Astronomers have discovered a new dwarf planet about 300 miles wide at the very edge of the solar system.

1:23 pm

Astronomers have discovered a new dwarf planet about 300 miles wide at the outer edge of the solar system.

The closest it gets to the Sun is 80 AU, or about 7.4 billion miles. More tantalizing, however,

… the findings also suggest the presence of another large planet in the outer reaches of the solar system. When the authors plotted the motion of Sedna, 2012 VP113, and distant Kuiper belt objects, they noticed some odd behaviors which they couldn’t explain — but which a massive, “super-Earth” planet about 250 AU away could. They note that such a dimly lit planet “would be fainter than current all-sky survey detection limits, as would larger and more distant perturbers” (i.e., planets), so it’s certainly possible… but right now it’s little more than a guess. A weird, intriguing guess.

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