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Shrinking Planets May Explain Why Hot Super-earths Exist

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vanishing gas giant

This artist’s concept shows giant clouds of hydrogen (blue) evaporating from the Neptune-sized exoplanet GJ 3470b as energetic charged particles from its host star beat down on the planet. The hydrogen is escaping the planet about 100 times faster than seen for any other similar alien world. (Credit: NASA/ESA/D. Player (STScI))

Astronomers have discovered a bizarre, Neptune-sized exoplanet located less than 100 light-years from Earth that’s shedding its atmosphere so quickly it may help researchers finally answer the long-standing question: Where did all the hot Neptunes go?

According to the new research, published December 13 in the journal Astronomy and Astrophysics, the shrinking world, named GJ 3470b, is rapidly losing its atmosphere as it’s bombarded by a steady stream of energetic charged particles from its red dwarf host.

The discovery — made with the help of NASA’s indefatigable Hubble Space Telescope — suggests that although Neptune-sized exoplanets can exist temporarily very near their host stars, they may not last very long. Instead, these planets could lose a significant fraction of their mass through evaporation driven by intense stellar winds. In the case of GJ 3470b, the researchers think strong winds from its active host star have stripped the planet of up to about 35 percent of its original mass over the course of its life.

“This is the first time a planet has been observed to lose its atmosphere so quickly that it can impact its evolution,” said lead author Vincent Bourrier, an astronomer from the University of Geneva (UNIGE), in a press release.

An Oasis in the Desert

Based on our own solar system, astronomers typically break down planets into three broad categories: rocky terrestrial planets (like Earth and Mars), massive gas giants (like Jupiter and Saturn), and freezing ice giants (like Uranus and Neptune). But over the years, researchers have discovered a multitude of exoplanets around other stars that seem to break these familiar molds.

In particular, since the first confirmed exoplanet was discovered just a few decades ago, researchers have uncovered a surprising number of giant planets, dubbed hot Jupiters, located extremely close to their host stars. On the other end of the spectrum, astronomers have discovered a plethora of hot super-Earths, which are a few times the mass of the Earth, that sit very near their stars. However, astronomers very rarely find medium-sized planets (or hot Neptunes) in similar close-in orbits.

But why does this void of hot, mid-sized planets — the so-called “hot Neptune desert” — exist?

hot neptune desert

This graphic plots known exoplanets based on both their size and their distance from their host stars. Hot Jupiters are in the upper left, while super-Earths are in the lower left. As shown, very few mid-size planets, or hot Neptunes, have been found orbiting very near their host stars. (For reference, the solar system’s innermost planet, Mercury, orbits the sun at an average distance of about 36 million miles.) (Credit: NASA/ESA/A. Feild (STScI))

“Until now, we were not sure of the role played by the evaporation of atmospheres in the formation of the desert,” said Bourrier. But based on this new finding, hot Neptunes may have withered away into mini-Neptunes (an alternative term for hefty super-Earths), or even eroded straight down to their rocky cores. “This could explain the abundance of hot super-Earths that have been discovered,” said co-author David Ehrenreich, an astronomer at UNIGE.

By showing that an active star can strip loads of mass from a mid-sized planet near the edge of the hot Neptune desert, the researchers think they’ve finally figured out why so few hot Neptunes have been discovered, while heaps of smaller planets, called super-Earths, have been found in the same boiling neighborhood.

“This is the smoking gun that planets can lose a significant fraction of their entire mass,” said co-author David Sing, a professor at Johns Hopkins University, in a statement. “GJ 3470b is losing more of its mass than any other planet we [have] seen so far; in only a few billion years from now, half of the planet may be gone.” And if GJ 3470b loses half its mass (it’s currently about 14 Earth masses), it will make the transition from hot Neptune to super-Earth.

Exploring the Desert

GJ 3470b, which sits about 10 times closer to its host star than Mercury is to the sun, is not the first evaporating Neptune-sized planet ever found. In fact, just a few years ago, astronomers found a similar planet named GJ 436b that is losing its atmosphere just like GJ3470b, albeit at a much slower rate (about 100 times slower). To analyze the mass loss of both these planets, the researchers tracked the hydrogen that was escaping from their atmospheres.

However, astronomers cannot easily detect hydrogen from more than about 150 light-years away. This is because the hydrogen signals they are looking for fall in a wavelength range that is blocked by interstellar gas, which permeates the space between stars. But fortunately, the researchers have a plan to seek out more distant shrinking hot Neptunes in the future.

“Helium will expand the range of our surveys,” said Bourrier, “the high sensitivity of the James Webb Space Telescope should allow us to detect helium escaping small planets, such as mini-Neptunes, and complete our observations of the edge of the desert.”

So, for now, we’ll have to be satisfied with just a few known examples of shrinking hot Neptunes. But keep in mind, many more may lurk just beyond the horizon.

 

[This article originally appeared on Astronomy.com]

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Ecology

Yukon and Northern BC First Nations tackle climate change using Indigenous knowledge and science

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YUKON, June 18, 2021 /CNW/ – The Government of Canada is working together in partnership with Indigenous and Northern communities in finding solutions to adapt to the impacts of climate change in the North.

Today, Minister of Northern Affairs, Daniel Vandal, along with Parliamentary Secretary to the Minister of Economic Development and Official Languages (Canadian Northern Economic Development Agency), Larry Bagnell, highlighted progress on three unique, Indigenous-led projects that are helping communities in Yukon and Northern British Columbia adapt to the challenges posed by climate change.

The Minister and Parliamentary Secretary met virtually with Carcross/Tagish First Nation (C/TFN) to learn about their community-led climate change monitoring program. C/TFN has partnered with Tsay Keh Dene Nation (TKDN) and Chu Cho Environmental of Prince George, British Columbia, to build a community-led monitoring project that examines environmental data and Indigenous knowledge to create a holistic picture of how the climate is changing across C/TFN and TKDN traditional territories. The project combines tracking of current and historical climate trends with knowledge shared by Elders while also providing opportunities for youth mentorship and climate change awareness.

The Taku River Tlingit First Nation (TRTFN) is also leading a unique project to assess the impacts of climate change within their traditional territory. Climate change is causing many of the culturally significant ice patches to melt, exposing organic artifacts to oxygen and leading to rapid deterioration. The TRTFN ice patch mapping project will involve performing archaeological assessments to prevent the degradation of artifacts. Research will be guided by traditional knowledge, Elders and oral histories, when available, and heavily involve community, Elders, youth and Knowledge Keepers.

The Pelly Crossing Selkirk Development Corporation is leading the Selkirk Wind Resource Assessment project through the installation of a Sonic Detection and Ranging (SODAR) system. The initiative includes a feasibility study leading up to the construction of a renewable energy facility, including wind, solar and battery energy storage. Expanding clean energy within the region will have direct benefits for communities, including reduced reliance on diesel, job creation and revenue generation for Selkirk First Nation. 

These projects are delivering important environmental, social and economic benefits that lead to healthier, more sustainable and resilient communities across Yukon and Northern British Columbia. They also build community clean energy capacity and help to avoid the impacts of climate change.

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Ecology

Atlantic Provinces Ready For Aquaculture Growth

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Aquaculture is an important economic driver for rural, coastal and Indigenous communities, and Atlantic Canada is well positioned to increase aquaculture production as global demand for sustainably sourced seafood grows.

That is why the ministers responsible for aquaculture in the Atlantic provinces have agreed to the ongoing development and management of their industries based on common principles. A new memorandum of understanding has been signed by the four ministers, which extends the previous agreement signed in 2008.

“In a time when food security is especially important, it is good to see our aquaculture industry has grown steadily and is poised for continued growth in 2021 based on environmentally responsible, science-based policies and practices,” said Keith Colwell, Minister of Fisheries and Aquaculture for Nova Scotia. “Our Atlantic partnership continues to help the industry grow sustainably.”

Cooperation between the provinces and the aquaculture industry has led to improvements in pest management, environmentally sustainable aquaculture methods, aquatic animal health and policies to support the shared use of marine and freshwater resources. It also aims to align regulation and policy between the provinces to make the regulatory requirements easier to understand by industry and the public.

Each province has a comprehensive and robust legislative and regulatory framework to ensure environmental sustainability, economic prosperity and public accountability. The provinces update their legislation and regulations regularly. Nova Scotia revamped its regulatory framework in 2015; New Brunswick received Royal Assent for a new Aquaculture Act in 2019 and is working on the supporting regulations; Newfoundland and Labrador completely revised its aquaculture policy in 2019; and Prince Edward Island has recently drafted a new Aquaculture Act.

The ministers have agreed to continue to use science-based evidence for management decisions, thereby increasing public and investor confidence in the Atlantic Canadian aquaculture industry.

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Ecology

COMING SOON: A Healthy Environment and a Healthy Economy 2.0

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We all want the same thing: a clean and responsible energy future for our children and future generations while continuing to enjoy a high standard of living.

On December 11, 2020, the Prime Minister announced a new climate plan which he claimed will help achieve Canada’s economic and environmental goals.

The proposed plan by Environment and Climate Change Canada (ECCC) entitled “A Healthy Environment and a Healthy Economy” will have an initial investment of $15 billion of taxpayer’s money. It is built on 5 pillars of action:

  1) Making the Places Canadians Live and Gather More Affordable by Cutting Energy Waste

2) Making Clean, Affordable Transportation and Power Available in Every Community

3) Continuing to Ensure Pollution isn’t Free and Households Get More Money Back

4) Building Canada’s Clean Industrial Advantage

5) Embracing the Power of Nature to Support Healthier Families and More Resilient Communities  

In my paper, “A Healthy Environment and a Healthy Economy 2.0” I will objectively critique each pillar in the government’s new climate plan and provide alternative solutions to the same issues.

  This is an alternative plan that supports workers, protects lower income earners and creates economic growth while respecting the environment and focusing on the dignity of work.

  This plan abandons virtue-signaling projects and relies on Canadian ingenuity to build our economy and restore Canada’s role of responsible leadership in the world.

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