Pic of the Week: The Rings of Neptune

Image (Credit): JWST image of Nepture showing its rings and moons. (NASA, ESA, CSA, STScI)

This week’s image is from the James Webb Space Telescope (JWST). It clearly shows the rings of Neptune as well as a number of its moons (the image below is a broader shot labeling those moons). It is an impressive shot by the JWST within our solar system, similar to the space telescope’s recent image of Jupiter.

Here is more about the image from NASA:

In this Webb image, Neptune resembles a pearl with rings that look like ethereal concentric ovals around it. There are 2 thinner, crisper rings and 2 broader, fainter rings. A few extremely bright patches on the lower half of Neptune represent methane ice clouds. Six tiny white dots, which are six of Neptune’s 14 moons, are scattered among the rings. The background of the image is black.

The Neptune image was uploaded to the NASA website on September 21, just a few days shy of the actual date in the calendar when Neptune was observed for the first time ever – September 23. The year was 1846 and the observer was German astronomer Johann Galle.

Image (Credit): JWST labeled image of Nepture showing its rings and moons. (NASA, ESA, CSA, STScI)

More JWST Priorities

Image (Credit): This diagram shows Lucy’s orbital path in green after her October 2021 launch to visit the Trojan asteroids. (Southwest Research Institute)

Last week I noted some of the mission priorities in the James Webb Space Telescope’s (JWST) first year. Those priorities were listed under “Exoplanets and Disks.” I thought I would highlight a few more, this time from the “Solar System Astronomy” list. Here are five more priorities:

  • Pluto’s Climate System with JWST;
  • The Moons of Uranus: A NIRSpec Investigation of Their Origins, Organic Constituents, and Possible Ocean World Activity;
  • A Pure Parallel Survey of Water in the Asteroid Belt;
  • DiSCo-TNOs: Discovering the Composition of the Trans-Neptunian Objects, Icy Embryos for Planet Formation; and
  • JWST Observations of Lucy Mission Targets.

Each of these priorities come with an explanation of the mission. For example, here is a little more about NASA’s Lucy mission from the JWST proposal:

The Lucy spacecraft – to be launched at approximately the same time as JWST – will perform the first ever in situ exploration of the Jupiter Trojan asteroids. Trojans are the largest population of solar system bodies currently unvisited by spacecraft, and revealing their composition and formation history is the key to untangling disparate hypothesis for the early dynamical evolution of the entire solar system.

Understanding these enigmatic bodies requires not just the high spatial resolution imagery and spectroscopy that will be afforded by Lucy, but also the superb near- and mid-infrared spectroscopy of which JWST is uniquely capable. The high signal-to-noise, high spectral resolution, and extended wavelength coverage beyond the capabilities of Lucy will allow JWST to sensitively probe the organic, carbonate, and silicate components of the surfaces of the Trojans. Meanwhile, the Lucy spectra and images will place these observations into their geological and historical context, greatly extending the scientific utility of both the JWST observations and the Lucy visit. Together these observations will paint a rich picture of this population, allowing us to trace connections with other bodies studied remotely and in situ across the solar system.

Lucy was launched last October and is expected to encounter its first Trojan asteroid until August 2027. You can find the full mission timeline here.

Television: More Space Stories This Summer

Image (Credit): The eight plants of our solar system. (NOVA)

If you are looking for space series beyond the Moon, PBS has a few more shows for you. With the James Webb Space Telescope releasing the first photos next week, now is the time to brush up on the mission with a NOVA special. And check out the earlier NOVA piece on the planets as well. Dates and times may vary by region.

NOVA: Ultimate Space Telescope, July 13 at 9pm (28 minutes):

How did NASA engineers build and launch the most ambitious telescope of all time? Follow the dramatic story of the James Webb Space Telescope—the most complex machine ever launched into space. If it works, scientists believe that this new eye on the universe will peer deeper back in time and space than ever before to the birth of galaxies, and may even be able to “sniff” the atmospheres of exoplanets as we search for signs of life beyond Earth. But getting it to work is no easy task. The telescope is far bigger than its predecessor, the famous Hubble Space Telescope, and it needs to make its observations a million miles away from Earth—so there will be no chance to go out and fix it. That means there’s no room for error; the most ambitious telescope ever built needs to work perfectly. Meet the engineers making it happen and join them on their high stakes journey to uncover new secrets of the universe.

NOVA: The Planets, July 7 & 14 at 8pm (5 episodes)

Among the stars in the night sky wander the eight-plus worlds of our own solar system—each home to truly awe-inspiring sights. Volcanoes three times higher than Everest, geysers erupting with icy plumes, cyclones larger than Earth lasting hundreds of years. Each of our celestial neighbors has a distinct personality and a unique story. In this five-part series, NOVA will explore the awesome beauty of “The Planets,” including Saturn’s 175,000-mile-wide rings, Mars’ ancient waterfalls four times the size of any found on Earth, and Neptune’s winds—12 times stronger than any hurricane felt on our planet. Using unique special effects and extraordinary footage captured by orbiters, landers and rovers, we’ll treat viewers to an up-close look at these faraway worlds. We’ll stand on the dark side of Pluto, lit only by the reflected light of its moons, watch the sun set over an ancient Martian waterfall, and witness a storm twice the size of Earth from high above Saturn. And, we’ll reveal how each of them has affected our own planet: Earth. 

Where Should NASA Travel To In The Years to Come?

Source/Credit: Voyager 2 image of Neptune and Triton from NASA/JPL-Caltech/Björn Jónsson.

In a recent posting, the non-profit Planetary Society is recommending NASA consider a return to Neptune and its moon Triton, noting that such a mission was part of the plan in the last Decadal Survey in 2010 along with trips to Mars and Europa (both of which are underway). NASA was aiming for Uranus or Neptune, but the Planetary Society stated a preference for Neptune.

The last and only visit to Neptune back in 1989 with NASA’s Voyager 2 spacecraft providing our first close view of the planet. The Voyager 2 mission also led to the discovery of six new moons as well as four rings around the planet. Moreover, the mission detected what may be underground oceans on the moon Triton.

The Planetary Society believes Triton, most likely a captured object from the Kuiper Belt, should be the deciding factor for visiting Neptune rather than Uranus. A 2019 paper, “The NASA Roadmap to Ocean Worlds,” highlights the value of visiting Triton to learn more about its potential oceans:

Triton is deemed the highest priority target to address as part of an Ocean Worlds Program. This priority is given based on the extraordinary hints of activity shown by the Voyager spacecraft (e.g., plume activity; smooth, walled plains units; the cantaloupe terrain suggestive of convection)…and the potential for ocean-driven activity given by Cassini results at Enceladus. Although the source of energy for Triton’s activity remains unclear, all active bodies in the Solar System are driven by endogenic heat sources, and Triton’s activity coupled with the young surface age makes investigation of an endogenic source important. Further, many Triton mission architectures would simultaneously address Ice Giant goals on which high priority was placed in the Visions and Voyages Decadal Survey. Finally, as Triton likely represents a captured Kuiper Belt object (KBO), some types of comparative planetology with KBOs could also be addressed in a Triton mission. Before the next Decadal Survey, a mission study should be performed that would address Triton as a potential ocean world; such a study could be part of a larger Neptune orbiter mission. The Decadal Survey should place high priority on Triton as a target in the Ocean Worlds Program.

The next Decadal Survey is being prepared now and among the papers submitted for consideration is this one highlighted by the Planetary Society – “Neptune and Triton: A Flagship for Everyone.” This paper states that a large strategic mission, called a “Flagship Mission,” to Neptune and Triton would have may benefits:

A Flagship Mission to Neptune and Triton would provide many firsts, an orbiter and atmospheric probe would not only be feasible on a Flagship budget, but achievable given the current state of the technology required by such a venture. This bold mission of exploration would be the first to orbit an ice giant to study the planet, its rings, small satellites, space environment, and the planetsized moon, Triton, itself a captured dwarf planet from the Kuiper Belt and a geophysically reactivated twin of Pluto. Broadly, the mission would address the following questions: How do the interiors and atmospheres of ice giant (exo)planets form and evolve? What causes Neptune’s strange magnetic field, and how do its magnetosphere and aurora work? What are the origins of and connections between Neptune’s rings, arcs, and small moons? Is Triton an ocean world? What causes its plumes? What is the nature of its atmosphere? and how can Triton’s geophysics and composition expand our knowledge of dwarf planets like Pluto?

It sounds like a strong argument to me. I imagine the other 500 or so papers submitted as part of the upcoming Decadal Survey have some other great scientific missions in mind as well. I look forward to seeing the final recommendations to NASA.