Please ensure Javascript is enabled for purposes of website accessibility Potential Contact Binary in Trans-Neptunian Belt Discovered

Discovery Channel Telescope Confirms Potential Contact Binary in Trans-Neptunian Belt

[vc_row][vc_column][vc_cta h2=”Feb 20, 2020 Update:”]As of February 2020, The Discovery Channel Telescope (DCT) is now known as the Lowell Discovery Telescope (LDT).[/vc_cta][/vc_column][/vc_row]

The Lowell’s Discovery Channel Telescope helps discover a potential contact binary at the edge of our Solar System.

Among the strangest small bodies in our Solar System are the contact binaries. A contact binary is made up of two objects that are touching or in contact with each other, resulting in a peanut-like shaped object. These systems have been found in the Near-Earth Object population, the main belt of asteroids, the Jupiter Trojans, the comet population and even at the edge of our Solar System.

The Trans-Neptunian Objects (or Kuiper belt Objects) orbiting the Sun beyond Neptune appear to have a large fraction or widely separated binary systems (i.e. natural satellites). Separated Trans-Neptunian binaries have a large variety of properties, from tiny satellites around large primaries to near equal-sized systems with primaries and secondaries having comparable sizes. The discovery of binary systems in the Trans-Neptunian belt is subject to observational limitations. Only widely separated and nearly equal-sized binaries are easily detected from the ground.

“The only efficient way to detect a contact binary in the distant solar system is from its lightcurve,” explains lead investigator Audrey Thirouin, a Postdoctoral Associate at Lowell Observatory. “The lightcurve of a contact binary has a very characteristic morphology with a deep V shaped pattern between the minimum and maximum of the lightcurve from shadowing effects between the two components, which presents a large change in the objects brightness while it rotates on its axis.”

“The Hubble Space Telescope is the most prolific telescope to find wide binary systems in the Trans-Neptunian belt,” said Keith S. Noll of the NASA Goddard Space Flight Center. “But, in the case of contact binaries, the Hubble Space Telescope is unable to resolve the components because of the small separation between the objects.”

“The first contact binary found in the Trans-Neptunian belt is 2001 QG298, found in 2004 by the Hawaii Kuiper Belt Variability project. Until now, only one other possible contact binary is known in the outer solar system.” said Scott S. Sheppard of the Carnegie Institution for Science-Department of Terrestrial Magnetism. Thus, this new find will help further shed light on how these mysterious objects formed. With the low number of expected objects in the current Trans-Neptunian belt of objects, of which Pluto is one of them, these contact binaries are unlikely to form. The population of objects had to be some 100 times or more populous in the past to create contact binaries from two objects passing near each other. The other possibility is that the contact binaries are a natural outcome planetesimal formation. A bunch of pebble sized particles could coalescing directly into a bigger object and with the right angular momentum, the pebbles can separate into two components, creating the contact binary at formation.

The team collected data of the Trans-Neptunian Object known as 2004 TT357 over the course of 2 years at the Lowell Observatory’s Discovery Channel Telescope (DCT) with the Large Monolithic Imager (LMI), which has some 37 million pixels forming its digital camera.

2004 TT357 is the faintest Trans-Neptunian Object observed for a lightcurve study with DCT. The team finds that the lightcurve of this object is best explained by a contact binary. Several lightcurves in future years will be needed to fully model the system and understand the characteristics of the components. The most likely option is that the two objects are in contact with a moderate density of 2 gcc and a mass ratio of about 0.4.

The full research paper has been accepted for publication in the Astrophysical Journal, with lead author Audrey Thirouin (Lowell Observatory) and co-authors Scott S. Sheppard (Carnegie Institution for Science) and Keith S. Noll (NASA Goddard Space Flight Center).