New Observations Show Planet-forming Disc Torn Apart by its Three Central Stars
A team of astronomers have identified the first direct evidence that groups of stars can tear apart their planet-forming disc, leaving it warped and with tilted rings.
This new research suggests exotic planets, not unlike Tatooine in Star Wars, may form in inclined rings in bent discs around multiple stars.
The results were made possible thanks to observations with the European Southern Observatory’s Very Large Telescope (ESO’s VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA).
Our Solar System is remarkably flat, with the planets all orbiting in the same plane. But this is not always the case, especially for planet-forming discs around multiple stars, like the object of the new study: GW Orionis. This system, located just over 1300 light-years away in the constellation of Orion, has three stars and a deformed, broken-apart disc surrounding them.
“Our images reveal an extreme case where the disc is not flat at all, but is warped and has a misaligned ring that has broken away from the disc,” says Stefan Kraus, a professor of astrophysics at the University of Exeter in the UK who led the research published today in the journal Science.
The misaligned ring is located in the inner part of the disc, close to the three stars.
The new research also reveals that this inner ring contains 30 Earth-masses of dust, which could be enough to form planets.
“Any planets formed within the misaligned ring will orbit the star on highly oblique orbits and we predict that many planets on oblique, wide-separation orbits will be discovered in future planet imaging campaigns, for instance with the ELT,” says team member Alexander Kreplin of the University of Exeter, referring to ESO’s Extremely Large Telescope, which is planned to start operating later this decade.
Since more than half the stars in the sky are born with one or more companions, this raises an exciting prospect: there could be an unknown population of exoplanets that orbit their stars on very inclined and distant orbits.
To reach these conclusions, the team observed GW Orionis for over 11 years. Starting in 2008, they used the AMBER and later the GRAVITY instruments on ESO’s VLT Interferometer in Chile, which combines the light from different VLT telescopes, to study the gravitational dance of the three stars in the system and map their orbits. “We found that the three stars do not orbit in the same plane, but their orbits are misaligned with respect to each other and with respect to the disc,” says Alison Young of the Universities of Exeter and Leicester and a member of the team.
They also observed the system with the SPHERE instrument on ESO’s VLT and with ALMA, in which ESO is a partner, and were able to image the inner ring and confirm its misalignment.
ESO’s SPHERE also allowed them to see, for the first time, the shadow that this ring casts on the rest of the disc. This helped them figure out the 3D shape of the ring and the overall disc.
The international team, which includes researchers from the UK, Belgium, Chile, France and the US, then combined their exhaustive observations with computer simulations to understand what had happened to the system.
For the first time, they were able to clearly link the observed misalignments to the theoretical “disc-tearing effect”, which suggests that the conflicting gravitational pull of stars in different planes can warp and break their discs.
Their simulations showed that the misalignment in the orbits of the three stars could cause the disc around them to break into distinct rings, which is exactly what they see in their observations. The observed shape of the inner ring also matches predictions from numerical simulations on how the disc would tear.
Interestingly, another team who studied the same system using ALMA believe another ingredient is needed to understand the system. “We think that the presence of a planet between these rings is needed to explain why the disc tore apart,” says Jiaqing Bi of the University of Victoria in Canada who led a study of GW Orionis published in The Astrophysical Journal Letters in May this year.
His team identified three dust rings in the ALMA observations, with the outermost ring being the largest ever observed in planet-forming discs.
Future observations with ESO’s ELT and other telescopes may help astronomers fully unravel the nature of GW Orionis and reveal young planets forming around its three stars.
Source: European Southern ObservatoryDate: Sep 3, 2020
Warnings for Phoenix (PSR) - National Weather Service
Be especially cautious with outdoor recreation on Labor Day Weekend as intense ... Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check ... Flagstaff AZ 244 AM MST Fri Sep 4 2020 AZZ018-037-051545- /O.CON. ... HIGH POLLUTION ADVISORY FOR MARICOPA COUNTY INCLUDING THE ...
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DataIsBeautiful is for visualizations that effectively convey information. Aesthetics are an important part of information visualization, but pretty pictures are not the sole aim of this subreddit.
"Phoenix has something called the “Brown Cloud,” where a nightly temperature inversion traps air in the valley where Phoenix sits, and that air picks up both pollution and already-existing dust from all over the area.
In the late 90s and early 2000s, Maricopa County was notoriously bad (at least among EPA officials) at regulation particulate pollution, and they were given until 2007 to solve the problem.
You can see it kept getting worse right up until the deadline, in no small part due to
the housing boom (massive increase in construction
transportation through the massive suburb that is Phoenix).
Unfortunately, this means Phoenix is quickly losing its status as a place to go for people with respiratory diseases, as the air here is consistently bad."
The health organization released its “State of the Air" report, now in its 20th year, Wednesday which included a ranking of the most polluted and cleanest U.S. cities according to air quality.
|Two new apartment communities are aiming to fill the void between affordable and luxury apartments in Phoenix. (Together they will add 478 units)
The first project, the $32 million, 226-unit Cabana on Washington, will welcome its first residents in April. The 252-unit Cabana on 12this also scheduled to open the same month. They will be the first new construction projects in the Cabana brand by Scottsdale, Ariz.-based Greenlight Communities.
According to Donna Kimura's article, "The firm aims to serve teachers, first responders, health-care workers, and others struggling with rising rents. These households earn too much for many affordable housing properties but not enough for the luxury communities being built in the booming Phoenix market, where “rent growth is expected to remain strong this year, bringing the average effective rent up to $1,280 per month after a 9.7% advance was registered last year,” according to a 2020 Marcus & Millichap forecast. . . Rents at the Cabana properties will be $300 to $500 per unit below market rates, In Greenlight’s model, all the communities are designed with individual buildings centered around large common courtyards that feature either pools, Zen gardens, outdoor fitness areas, and other amenities designed to encourage community interaction. Just as Cabana on Washington and Cabana on 12th are wrapping up construction, the firm plans to begin construction on two projects in Scottsdale and Mesa, Ariz., in the next several months. . . LINK > Housing Finance ________________________________________________________________________ THIS IS #3 MultiHouising News June 10, 2020 Greenlight Communities just received a $22.9 million construction loan to develop Cabana on 99th, a 286-unit community in Glendale
JLL secured the funds for the developer and facilitated a joint venture equity partnership with Bridge Investment Group.
Greenlight Communities has received a $22.9 million construction loan for the development of Cabana on 99th, a 286-unit community project in Glendale, Ariz. Western Alliance Bank provided the mortgage, according to public records. JLL Capital Markets assisted the borrower and secured a joint venture equity partnership with Bridge Investment Group. Located on 10 acres at 10000 W. Missouri Ave., the property has a projected completion date in 2021. The amenity package will feature a pool, a common area serving as co-working space, and outdoor barbecue stations. The property is close to a wide variety of shopping and dining options along West Camelback Road and some 17 miles from downtown Phoenix. In January, the developer acquired the site for $3.5 million from a private investor in an all-cash transaction, Maricopa County records show. The new development will provide one- and two-bedroom apartments of attainable workforce housing. Last month, Greenlight delivered two other Cabana-branded communities, providing 478 units of attainable housing in Phoenix. The JLL brokerage team that secured the funds included Senior Director Brad Miner, Managing Director Bryan Clark and Analyst Daniel Pinkus.
Scottsdale-based Greenlight Communities broke ground on Cabana on Power, a 244-unit multifamily development in Mesa. The site is located at 6151 S Power Rd. and the “attainable” housing project is expected to fill the void between affordable and luxury apartments.
The land was acquired last October, and construction is set for completion in the summer of 2021. The project will include 102 studio, 96 one-bedroom, and 46 two-bedroom apartments.
Greenlight Communities’ Patricia Watts says, “At Greenlight Communities we have remained steadfast in our pursuit to build over $300 million of attainable housing apartments in the Phoenix metro area.
Mesa will be our fourth community to be completed in the Valley and we are excited to be providing residents in the Southeast Valley the same affordable options that we are now currently leasing in Phoenix.”
AZ Fire Officials Consider Launching Ambulance Service Jim Walsh East Valley Tribune (Mesa, Ariz.) 08.31.2020
Mesa's city council is expected to approve the purchase of six ambulances, doubling the city's fleet and laying a foundation for the Mesa Fire and Medical Department to start its own service.
"With a long-term contract with industry giant American Medical Response, or AMR, about to expire at the end of November, Mesa is exploring its options.
While no final decision has been made, the Mesa City Council is expected to authorize the purchase of six new ambulances on Monday at a cost of $1.6 million, doubling the city’s fleet to 12.
The move comes almost a week after Gilbert Town Council did the same thing, voting to purchase six ambulances and replace AMR – a move that company officials called unwarranted.
Candace Cannistraro, Mesa’s management and budget director, said the funding comes from the Ambulance Transport Fund that comprises revenue generated from patients using the service.
"
