Tag Archives: KBO

Moon discovered orbiting Kuiper Belt Object Makemake

Worlds without end: Astronomers have discovered a moon orbiting Makemake, the fouth largest object in the Kuiper Belt.

A nearly edge-on orbital configuration helped it evade detection, placing it deep within the glare of the icy dwarf during a substantial fraction of its orbit. Makemake is one of the largest and brightest known Kuiper Belt Objects (KBOs), second only to Pluto. The moon is likely less than 100 miles wide while its parent dwarf planet is about 870 miles across. Discovered in 2005, Makemake is shaped like football and sheathed in frozen methane.

Tracking this moon’s orbit will help astronomers get a better understanding of Makemake itself, whose oblong shape has baffled them since its discovery.

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.

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.

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.

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.

New Horizons — on its way to Pluto — will take a look at a different Kuiper Belt object in January 2015.

New Horizons — on its way to Pluto — will take a look at a different Kuiper Belt object in January 2015.

The encounter will take place at a range of about 75 million km, a distance somewhat subject to change depending on how the probe makes its course correction. At such a great distance, New Horizons will not be able to discern features on the surface of the KBO, nor will it be able to make spectroscopic observations to try to determine the composition of the surface material.

However, New Horizons will be in an excellent position to look for small, close-in moons around the object. It will also be in a position to observe the object’s phase curve, which is a measure of how the reflectivity of the surface changes as a function of viewing angle. This will reveal a great deal about the fluffiness of the surface material (note – fluffiness is a technical term meaning, roughly, “the opposite of dense”). These two observations cannot be made from Earth, even with the most powerful telescopes available.