GW Orionis is a triple star system roughly 1,300 light years from Earth sitting within an extended protoplanetary disc that surrounds all three. This disc has been intriguing astronomers for the last decade, and now a team believe they have evident that the disc is home to at least one planet.
Systems of multiple stars bound by gravity are believed to be at least as common within our galaxy as single-star systems (like the Sun), and as such have oft been depicted as the home of worlds with exotic skies (think Star Wars and Tatooine’s iconic binary sunsets). But if correct, this will be the first time we have discovered a planet occupying a circumtriple orbit.
Using observations from the powerful Atacama Large Millimetre/sub-millimetre Array (ALMA) telescope in Chile, a team of astronomers set out to analyse the extended dust ring surrounding the three stars and they orbit their common centre, only to discover that rather than being fairly uniform, the dust ring has a substantial and persistent gap within it.
After running through a wide range of simulations to explain the gap, including trying to find some bizarre form of “gravitational torque” imposed on the disc by the three stars, the team resorted to Occam’s Razor: the simplest explanation is likely the most correct. In this case, and as several of their models demonstrated, the most consistent means to create such a gap in the disc is to plonk at least one large planet, around the size of Jupiter, into it.
It’s really exciting because it makes the theory of planet formation really robust. It could mean that planet formation is much more active than we thought which is pretty cool.
– Jeremy Smallwood, study lead author
In fact, such is the size of the gap, it is conceivable that it might be home to several planets – all of which are far too faint and too distant to be directly observed, but some of which might be Earth-sized solid bodies. This doesn’t mean they might harbour life, but they would make for a fascinating study.
Further work is to be conducted in an attempt to confirm the team’s findings and possibly refine their model of this complex system.
NASA Round-Up
SLS Launch “Likely” to Slip to 2022
As I’ve noted in a number of Space Sunday updates recently, the first flight of NASA’s Space Launch System (SLS) rocket has increasingly looked like it will slip back into 2022, the result of a number of programmatic slippages that, together with restricted working practices introduced by NASA during a good part of 2020 to deal with the SARS-CoV-2 situation, have resulted in most / all of the “spare” time built into the programme to handle unanticipated delays being been eaten up.
Speaking on September 30th, 2021, NASA Associate Administrator Bob Cabana noted that while the agency was not committed to a specific launch date other than “late 2021” for the mission – called “Artemis 1” and intended to fly an uncrewed Orion capsule around the Moon and back in an extended flight – it will now “more than likely” see it slip into early 2022.
The vehicle stack of core stage, upper stage and solid rocket boosters have just completed a series of “modal tests” within the Vehicle Assembly Building (VAB) at the Kennedy Space Centre, Florida. These involved subjecting the stack to a range of vibrations and shaking it to determine the full range of frequencies and vibrations it will experience during launch and ascent in order to programme the flight software and navigation systems so they can be correctly responded to, and an deviance from the “norms” identified and dealt with.
These tests should have been completed in August 2021, paving the way for the Orion capsule and its service module to be mated with, and integrated into, the rocket. This work is now scheduled to commence on October 13th. After that, the entire stack will be rolled out to Launch Complex 39B for a wet dress rehearsal in which the core stage is loaded with propellants in a practice countdown that stops just before ignition of the four main RS-25 engines. Following the test, the rocket will roll back to the VAB for final reviews and pre-launch preparations, before taking a final ride to the pad ready for launch.
Space Telescopes Update
NASA’s James Webb Space Telescope (JWST), the next great space-based telescope, remains on course for a December 18th, 2021 launch. However, the observatory continues to be a source of controversy.
JWST is named for James E. Webb, the second NASA Administrator to be appointed, and the man who saw the agency through the Mercury and Gemini programmes – the latter critical to the Apollo lunar landings – between 1961 and 1968. However, prior to that, he served as Undersecretary of State from 1949–1952, a period which saw the “Lavender Scare”, when many LGBTQ people were driven from roles in government service – a fact that recently (and somewhat belatedly, given the life-time of the programme) has given rise to calls for the telescope to be re-named.
NASA had said it would look into the matter, but this week – without formal announcement or indication of precisely how it did so – leaked word via National Public Radio in the United States that it has conducted “an investigation” and found “no cause” for the telescope to be renamed. The decision and the manner in which NASA has handled it have heaped scorn upon the agency by those who launched the campaign and who signed a petition on the matter forwarded to NASA – many of whom are from the science and astronomy communities.
Elsewhere, the next space-based telescope NASA will launch after JWST – the Nancy Grace Roman Space Telescope (formerly WFIRST) – has received both good and bad news.
The good news is, the telescope successfully passed its critical design review, signalling that all developmental engineering work is now complete, and it can move on to the assembly and testing of the telescope itself.
A next-generation observatory, the NGRST will peer across vast stretches of space and time to survey the infrared universe. Thanks to the mission’s enormous field of view and fast survey speeds, astronomers will be able to observe planets by the thousands, galaxies by the millions, and stars by the billions. As such, it is very much an heir to the Hubble Space Telescope (HST) on which parts of it are based, and entirely complimentary to the work of JWST.
The bad news is that the telescope – which the Trump Administration repeatedly tried to cancel despite its real-time low cost thanks to its use of “spare” HST elements – has now genuinely started to incur cost overruns. These are the direct result of the SARS-CoV-2 pandemic in 2020 as a result of the restrictive working practices NASA had to implement to protect their employees, together with disruption of critical supply chains also as a result of the pandemic. These have already caused a US $400 million increase in the telescope’s estimate US $3.9 billion cost, and further increases are now expected – although there is sufficient leeway in the NASA 2021-2022 budget to meet the added costs and the estimated 7-month delay so far incurred in the telescope’s development.
Continue reading “Space Sunday: strange worlds, telescopes and rockets”
Inara Pey: Living in a Modemworld 