A pair of Columbia University astronomers using NASA’s Hubble Space Telescope and Kepler Space Telescope have assembled compelling evidence for the existence of a Neptune-size moon orbiting a gas-giant planet 8,000 light-years away. If their findings are correct, it will be the first moon found orbiting a planet beyond our solar system.
The planet, Kepler 1625b, is between 5.9 and 11.67 times the size of Jupiter. It orbits a G-class main sequence star with around 8% more mass than our own in the constellation of Cygnus, every 287.4 days. The planet has been known about for some time, but whilst re-examining the data gathered by the Kepler space observatory that led to its discovery, Alex Teachey and David Kipping from the University of Columbia noticed anomalies in the way the planet dimmed the star’s light as it transited between the star and Kepler – anomalies that in ordinary circumstances should not have been there, but which were enough to get the astronomers 40 hours observing time using the Hubble Space Telescope.
Able to study the star with four times greater precision than Kepler, HST was used to observe Kepler 1625 both before and during one of the planet’s 19.5 hour transits across the star. In doing so, it recorded not only the anticipated dip in the star’s brightness, but also a second dimming along the same orbital path, starting some 3.5 hours after the first had started. The Hubble data also revealed that Kepler 1625b started its transit across the star 1.25 hours earlier than it should have.
When put together, the most likely explanation for both the “premature” transit and the extra dimming of light from Kepler 1625 is that a vary large, somewhat distance moon is orbiting the Jupiter-like Kepler 1625b. The presence of such a body in orbit would set a common barycentre (centre of gravity) between the planet and the moon that would cause the planet to “wobble” from its predicted location in its orbit, leading to variations in the start times for transits. Similarly, the presence of a large moon orbiting it would cause the additional dimming in the star’s brightness during a transit.
Before the exomoon’s existence can be confirmed, further observations by Hubble are required. However, the preliminary data gathered suggests it could be around 1.5 percent the mass of its parent star – which is a very close mass-ratio between the Earth and its moon. However, given both the massive planet and its moon appear to both be gaseous in nature, should the moon’s existence be confirmed, it raises intriguing questions as to how it was formed.
In the case of solid satellites like the Moon, their creation is likely due to a collision between Earth and another planetary body that left debris that coalesced into the Moon. Such a path of formation for a gaseous body, however, is exceptionally unlikely: anything impacting with Kepler 1625b, for example, would likely be absorbed into it, rather than throwing off matter to form a separate orbiting body.
One of the most intriguing theories for the moon’s possible existence is that it may have started life as a separate planet orbiting Kepler 1625, but over time it came under the gravitational influence of the massive Kepler 1625b, and over time was drawn into orbit around it. If this should prove to be the case, it could have interesting implications for future exoplanets and the moons that may be found orbiting them.
NASA Delays Commercial Crew Launches and Tensions with Russia Increase
NASA has confirmed that the first uncrewed test flights of the SpaceX Crew Dragon and Boeing CST 100 Starliner commercial crew transports intended to fly astronauts to the International Space Station (ISS) have been delayed.
Under the original schedule, the uncrewed flight test for Crew Dragon had been scheduled for November 2018 and would have been followed by a 2-week crewed flight with NASA astronauts Bob Behnken and Doug Hurley in April 2019. Under the new schedule, these flights will now occur in January and June 2019 respectively.
Similarly, the first uncrewed flight for the CST-100 Starliner is now planned for March 2019 with the crewed test previously scheduled for mid-2019 now set for August 2019.
If SpaceX and Boeing maintain the new schedule, NASA believe the first operational commercial crew mission could take place in August 2019 – which would suggest a Crew Dragon would be the vehicle used, given the CST-100 would just have completed its crewed test flight, requiring some post-mission analysis. The second operational will then follow in December 2019. Both of these dates straddle the end to the US government’s extended contract to use seats on Russia’s Soyuz vehicle to send US astronauts to and from the ISS.
While unrelated, the news of the delays came as US / Russia tensions concerning the hole found in a Soyuz capsule became strained once more.
As I’ve previously noted (see here and here), at the end of August a slow leak was detected in a Soyuz MS-08 docked at the ISS. Initially, it was thought the hole causing the leak was the result of debris puncturing the Soyuz hull. However, it emerged the hole appears to have been drilled. Core thinking around it was that a mistake had been made during the vehicle’s fabrication or in preparing it for flight at the Baikonur cosmodrome, and then hastily covered up. In either case, it is believed a substance unfit for purpose was used in the repair, which gradually degraded in space prior to failing completely, causing the pressure loss.
However, fuel was poured on the embers of speculation in September when Russian media reported the hole may have been cut in space, possibly by one or more US astronauts – and the initial source for these claims was the director of the Russian space agency Roscosmos, Dmitry Rogozin. The claims resulted in some anger, mission commander Andrew “Drew” Feustel issuing a strongly worded statement from the space station, with NASA and Roscosmos attempting to push back on the rumours.
At the start of October, Feustel returned to Earth with fellow astronaut Ricky Arnold and cosmonaut Oleg Artemyev, Rogozin aboard the second of the two Soyuz vehicles docked at the ISS, and just days afterwards, Rogozin repeated his extraordinary claims, stating that a preliminary report on the leak showed that the hole was not the result of a manufacturing defect, implying it was deliberate and may have been done in space. At the same time, he threw shade on the US Government, claiming unnamed American officials have been “interfering” in the Russian space agency’s cooperation with NASA.
Nor was that all. In his statement, Rogozin accused SpaceX of attempting to squeeze Russia out of the space launch services market, and also pointed a finger at the US Air Force’s secretive X-37 mini-shuttle programme, re-stirring the theories that it is some form of weapons platform.
Americans have this thing, the X-37. We don’t understand its purposes. Rather, we do understand, but we have not received an official explanation. Essentially, this thing can be used as a weapons carrier.
– Roscosmos chief Dmitry Rogozin, Monday, October 1st, 2018
How this all pans out remains to be seen. NASA Administrator James Bridenstine in due to meet Rogozin at Baikonaur later this month, while ISS astronauts are planning a spacewalk in November to gather more information on the hole, as the Soyuz remains docked at the ISS.
New Solar System Dwarf Planet Confirmed
Astronomers led by Scott Sheppard from Carnegie University and using the Subaru Telescope on Mauna Kea, Hawaii, have discovered the latest dwarf planet orbiting the Sun. Catalogued as 2015 TG387, it has been informally nicknamed The Goblin, and it sits within one of the most extreme orbits around the Sun so far discovered, never coming closer to the Sun than 65 AU (65 times the distance from the Earth to the Sun) and extending as far out as 2,300 AU.
Confirmation of its existence has been three years in the coming; as its official name indicates, the tiny world was first located in 2015. However, such is the enormous distance between it and Earth and the speed with which it moves along its orbit – it takes around 40,000 years to go around the Sun -, Sheppard and his team required several years to confirm its existence. The informal name came from The Goblin being discovered at Halloween, and it is one of a group of objects that are also called Inner Oort Cloud Objects (IOCOs), a group that includes 2012 VP113, and Sedna, both of which also have eccentric orbits around the Sun, and are part of a growing group of such bodies astronomers are trying to use to locate the mysterious Planet X (or Planet 9), a large planet approximating to Neptune, thought to be occupying an orbit heavily inclined to the plane of the ecliptic and which carries it around the Sun at an extreme distance.
In particular, this group of objects, which have widely dispersed eccentric orbits, all have more-or-less common points of perihelion (point of closest approach to the Sun, which strongly suggest they have been pulled out of the plane of the ecliptic and into their odd elliptical orbits by the gravitational influence of a large body somewhere far out in the outer solar system – although whether or not that body is indeed a planet is itself the subject of debate. The hope is that by locating more objects like The Goblin and mapping their orbits, astronomers will be able to build a model of the likely orbit for whatever is influencing them, greatly narrowing where they need to look in order to find the object itself.
The Goblin is estimated to be about 300 km (190 mi) in diameter – roughly half the radius of Pluto’s Charon, and one-third that of the radius of Sedna, making it a relatively small object, and at perihelion it is almost twice the distance of Pluto from the Sun. Other than this, not a lot more is currently known about it.
Lockheed Martin Reveal Lunar Lander Concept and Boeing Plans SLS Upper Stage Changes
Lockheed Martin has revealed a concept spacecraft able to land on the lunar surface as a part of US plans to return a human presence to the Moon some time in the 2020s. The vehicle is intended to operate between the proposed Lunar Orbital Platform-Gateway (LOP-G) and the surface of the Moon, and was unveiled at the 69th annual International Astronautical Congress ( ) in Bremen, Germany, on October 4th, 2018.
Looking a little like the oversized offspring of a liaison between the Apollo Lunar Excursion Module (LEM) and R2D2, the vehicle is designed to deliver a crew of four to the surface of the Moon, together with up to one tonne of equipment and supplies, and remain there for up to two weeks at a time as a base of operations for surface studies and exploration. Part of the cargo would be a small, unpressurised rover vehicle, possibly similar in nature to the rover used during Apollo missions 15 through 17.
Meanwhile, Boeing has confirmed plans to change part of the upcoming Space Launch System (SLS). Originally, the SLS was due to fly in June 2020 in what’s called the block 1 configuration, featuring the Interim Cryogenic Propulsion Stage (ICPS), which was to have been used just the once before being swapped to the more powerful Exploration Upper Stage (EUS) in what is called the SLS block 1b configuration.
These plans have now changed due to NASA requesting the performance of the EUS is enhanced so the block 1b variant of SLS will be capable of lifting “co-manifested” payloads into orbit. That is, launching two large payloads such as two elements of the LOP-G on a single vehicle, rather than having to use separate rockets.
Boeing believe the work can be done – but it will take additional time. As a result, the decision has been made to utilise the block 1 / ICPS booster for the first four SLS flights, rather than only the first. These flights will be:
- Exploration Mission 1 (EM-1), an uncrewed flight of the Orion MPCV and service module on an extended 25-day mission around the Moon and back, scheduled for June 2020.
- Exploration Mission 2 (EM-2), a crewed flight of the Orion MPCV and service module on a 9-day mission around the Moon and back with four crew, scheduled for June 2022.
- Exploration Mission 3 (EM-3), a crewed flight of the Orion MPCV and service module on an extended (16-26 day) mission to a lunar halo orbit (the type of orbit the LOP-G will occupy) and back with four crew, scheduled for late 2022.
- Europa Clipper, the launch of NASA’s flyby mission to Jupiter and its icy moon, Europa, currently scheduled for 2023.
However, in order for at least two of these launches to go ahead (EM-2 and EM-3), the ICPS will have to go through additional flight certification so that it can be used with crew launches – something that was not originally a requirement in its ICPS design specifications.
In the meantime, the changes to the flight schedule mean that the first SLS block 1b mission using the uprated EUS will now take place in 2024, delivering the first two elements of the LOP-G to a L2 Southern Near Rectilinear Halo Orbit (NRHO), together with 4 crew in 30-day mission.