New Horizons team spots stellar eclipse by 2014 MU69

In an effort to learn as much as possible about New Horizons’ next target, Kuiper belt object 2014 MU69, the science team has successfully observed on July 17 a 0.2-second-long eclipse of a star by that object.

This was the third occultation by 2014 MU69 that the science team attempted to catch. With the first, on the ground, they saw nothing. The second, using the flying observatory SOFIA, was more successful, as was the third attempt last week.

Though they haven’t yet released their findings, they say the data from the last two observations has allowed them to determine the rough shape and size of 2014 MU69. This is crucial information needed for planning the observations of it during New Horizons January 1, 2019 fly-by.

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.

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.