Top Astronomy Stories in 2023

Posted on by onespaceman2000
Image (Credit): Chart showing the planned travel of the JUICE spacecraft. (ESA, work performed by ATG under contract to ESA)

I wanted to start out the new year by first remembering all of the great missions from 2023. I also decided to group this work rather than focus on single missions.

Here is what I came up with:

NASA’s Moon Mission: We saw more progress towards the next steps in the Artemis program to put humans on the Moon, including NASA’s announcement of the four astronauts to lead the Artemis II mission, SpaceX’s tests of the Starship rocket, and the design of new spacesuits for the Artemis astronauts.

Other Attempts to Land on the Moon: We saw other nations also reaching for the Moon. While India had great success landing a rover on the lunar South Pole, both Russia and a commercial venture from Japan did not have similar luck. We also saw Japan trying it again late last year.

NASA Asteroid Missions: Asteroids were the big news this year, with Lucy encountering a surprise pair of asteroids, OSIRIS-REx bringing back a sample from the asteroid Bennu, and NASA launching the Psyche mission.

JWST Discoveries: This year we celebrated the anniversary of the James Webb Space Telescope (JWST), which has been better than ever imaged. It is helping to change our understanding of the origin of the universe while poking and prodding at exoplanets to review their secrets.

ESA Missions: The European Space Agency (ESA) has also been very busy in 2023. For instance, the launch of the Euclid mission to study dark matter and dark energy, as well as the JUICE mission to study Jupiter and its moons, will assist with our understanding of the big picture as well as our own neighborhood.

That’s an impressive record, and I look forward to even more great news in 2024.

Study Findings: Atmospheric Carbon Depletion as a Tracer of Water Oceans and Biomass on Temperate Terrestrial Exoplanets

Posted on by onespaceman2000
Credit: NASA/JPL-Caltech

Nature Astronomy abstract of the study findings:

The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O2, will be challenging to detect with present or upcoming observatories. Here we suggest a new signature. A low carbon abundance in the atmosphere of a temperate rock`y planet, relative to other planets of the same system, traces the presence of a substantial amount of liquid water, plate tectonics and/or biomass. Here we show that JWST can already perform such a search in some selected systems such as TRAPPIST-1 via the CO2 band at 4.3 μm, which falls in a spectral sweet spot where the overall noise budget and the effect of cloud and/or hazes are optimal. We propose a three-step strategy for transiting exoplanets: detection of an atmosphere around temperate terrestrial planets in about 10 transits for the most favourable systems; assessment of atmospheric carbon depletion in about 40 transits; and measurements of O3 abundance to disentangle between a water- versus biomass-supported carbon depletion in about 100 transits. The concept of carbon depletion as a signature for habitability is also applicable for next-generation direct-imaging telescopes.

Citation: Triaud, A.H.M.J., de Wit, J., Klein, F. et al. Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets. Nat Astron (2023).
https://doi.org/10.1038/s41550-023-02157-9

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NASA Had a Busy Year

Posted on by onespaceman2000
Image (Credit): The introduction of the Artemis II crew, just one of many items highlighted in NASA’s new video summarizing 2023. (NASA)

This is the time of year for lists, so I wanted to highlight one of the more important lists, at least in the opinion of this writer. That’s right, we need to remember the important space milestones from this year.

Fortunately, NASA recently summed up its successes in 2023 with a new video titled NASA 2023: Nothing is Beyond Our Reach. The video highlights many of the Agency’s accomplishments this year, including the launch of the Psyche mission, the announcement of a crew for the Artemis II mission, and the OSIRIS-REx capsule retrieval.

It is quite a list. Luckily, NASA provided a list of links so you can read more about the various efforts:

Time to read up on 2023 before we dive into more activities in 2024.

Note: You can read a more detailed list of accomplishments at this NASA site.

Pic of the Week: Supernova Remnant Cassiopeia A

Posted on by onespaceman2000
Image (Credit): Supernova Remnant Cassiopeia A. (NASA, ESA, CSA, STScI; D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent))

This week’s image captured by the James Webb Space Telescope is both violent yet beautiful. It is also NASA’s Astronomy Picture of the Day for today.

Here are some details about the image from NASA:

Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in planet Earth’s sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of the expanding blast wave is about 20 light-years across. Light echoes from the massive star’s cataclysmic explosion are also identified in Webb’s detailed image of supernova remnant Cassiopeia A.

Study Findings: A Resonant Sextuplet of Sub-Neptunes Transiting the Bright Star HD 110067

Posted on by onespaceman2000
Image (Credit): Neptune as captured by the James Webb Space Telescope’s near-infrared camera. (NASA, ESA, CSA, and STScI)

Nature abstract of the study findings:

Planets with radii between that of the Earth and Neptune (hereafter referred to as ‘sub-Neptunes’) are found in close-in orbits around more than half of all Sun-like stars. However, their composition, formation and evolution remain poorly understood. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕ to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

Citation: Luque, R., Osborn, H.P., Leleu, A. et al. A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067. Nature 623, 932–937 (2023).
https://doi.org/10.1038/s41586-023-06692-3

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