Mission: Hayabusa 2 Options

[Marcin600]

New interesting article about pebbles flying over the Ryugu surface during touchdowns and more... (open access):

https://www.science.org/doi/10.1126/science...24?utm_campaign
https://www.science.org/doi/epdf/10.1126/science.abj8624
https://www.isas.jaxa.jp/en/topics/002943.html

[Tom Tamlyn]

Good article by Dr. Elizabeth Tasker discussing the last of the three papers linked above by member Marcin600, Tachibana, et al., "Pebbles and sand on asteroid (162173) Ryugu: in situ observation and particles returned to Earth," Science, 10 February 2022.

Hayabusa2 bagged ~5g of grains from asteroid Ryugu. But can 3 playing cards in weight really tell us about the whole asteroid? If not, then our deductions about the Earth’s beginnings will be wrong. My latest @NExSSManyWorlds, research by @ShogoCitrus🔗: https://manyworlds.space/2022/02/13/can-we-...steroid-sample/

https://twitter.com/girlandkat/status/1493085869682479104

Dr. Tasker is an astrophysicist who studies star and planet formation, and also a very good popular science writer. She tweets about her work at the Japan Aerospace Exploration Agency (JAXA), and about her life with a cat. She's worth following. https://twitter.com/girlandkat

[Marcin600]

Reading all these texts convinces me that these small pebbles brought to the Earth by Hayabusa2 are a perfect reflection of the vast majority of rocks, boulders and stones on the surface of Ryugu. They look the same, have the same texture, structure, color, chemical composition, cracks, etc. etc. So, these small grains are for researchers the same as large stones - if, for example, they were brought by astronauts landing on Ryugu!

In fact, it looks as if Ryugu has an almost fractal structure!
[A similar phenomenon was observed by the Rosetta probe and the Philae lander on the nucleus of comet Churyumov-Gerasimenko. It might just be a feature typical of primitive (little modified) Worlds in the Solar System (and maybe not only here!).]

However, I am a bit disappointed with the complete absence of chondrules and CAIs (calcium-aluminum-rich inclusions) in the Ryugu material, and common in chondrites
I was hoping to finally see the natural "chondrite rock" - the mythical „oldest and most primeval rock” and „source of chondrite meteorites”...

[Marcin600]

The ~700-meter near-earth asteroid 2001 CC21 (98943) - target of Hayabusa2 July 2026 flyby - as seen on February 1, 2022 by Bisei Spaceguard Center (BSGC) 1 m telescope (approximate brightness of CC21 is 18.4 mag):
https://www.hayabusa2.jaxa.jp/topics/20220218_2001_CC21/ (with movie)
Crdit: JAXA, Imaging: JSF/JSGA

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[Marcin600]

In this video from yesterday “JAXA Sagamihara Campus Online Special Opening”, day 2, March 26, 2022
https://www.youtube.com/watch?v=zdXrf-4tb6M
from 3:27:20 until 3:42:03
there are some interesting videos of laboratory testing of Ryugu samples in ASRG Extraterrestrial Sample Curation Center clean room (audio in Japanese)

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[pbanholzer]

Ryugu samples closely match primitive CI meteorites like. Ivana and Orgeil.
https://www.science.org/doi/10.1126/science.abn7850

[Dysgraphyk]

Surprisingly (to me) one of the conclusions of this study is that the parent body from Ryugu experienced conditions with liquid water at 37°C:

Abstract : Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37 ± 10°C. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles the Sun’s photosphere than other natural samples do.

https://www.science.org/doi/10.1126/science.abn7850

Was it expected to find such conditions in the early solar system formation?

[nprev]

We've discovered meteorites that show evidence of exposure to liquid water during formation. Some like Murchison even have halite crystals. My understanding is that it's thought that during the accretion phase conditions inside of at least some parent bodies were (briefly) able to sustain layers or small pockets of liquid water but of course they cooled very quickly thereafter and the water was largely driven off during subsequent impacts and fragmentation of the original planetesimals.

[Marcin600]

Abstracts from presentations given at the “Hayabusa symposium 2021” have now been released:
https://curation.isas.jaxa.jp/symposium/abs...t/abs_2021.html

Topics include sampling of asteroids Ryugu and Bennu, but also Itokawa, Moon, meteorites and future ones: Phobos and Mars.
For me, the following abstracts seem particularly interesting:
„JAXA Detailed Description -Variation of surface characteristics of Ryugu returned samples” Nakato A. et al. - https://curation.isas.jaxa.jp/symposium/abs...S2-3_Nakato.pdf
„Surface morphologies and space weathering features of Ryugu samples” Matsumoto T. et al. - https://curation.isas.jaxa.jp/symposium/abs...6_Matsumoto.pdf
„CNHOS contents with their isotopic compositions and preliminary organic profiles from the Hayabusa2 samples” Yoshinori T. et al. - https://curation.isas.jaxa.jp/symposium/abs...S3-7_Takano.pdf
„Color Mapping of Asteroid Bennu” DellaGiustina D.N. et al. - https://curation.isas.jaxa.jp/symposium/abs...llaGiustina.pdf
„Hydrothermal history of (162173) Ryugu’s parent body inferred from remote-sensing data” Tatsumi E. et al. - https://curation.isas.jaxa.jp/symposium/abs...4-3_Tatsumi.pdf
from this abstract - on Phaethon: „...The similarity for both Ryugu and Phaethon, that neither exhibits a strong UV nor 2.7-µm OH-band absorption for the entire rotational phases, might result in similar spectral changes due to space weathering on both asteroids. Thus, the majority of Phaethon’s surface could be explained by freshness due to rejuvenation caused by the recent encounter with the Sun, i.e. fresh cometary activity...”

„The young basalts on the Moon: Pb–Pb isochron dating in Chang’e-5 Basalt CE5C0000YJYX03501GP” Liu D. et al. - https://curation.isas.jaxa.jp/symposium/abs...21/S6-7_Liu.pdf

[Marcin600]

Hayabusa2 press briefing, June 29, 2022 (in English), very informative:
https://www.hayabusa2.jaxa.jp/enjoy/materia...9_ver13_en2.pdf

- Project results
- Sample analysis
- Ryugu history
- Extended Mission
- Current status of spacecraft operation

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[abalone]

Grains of dust from asteroid Ryugu older than our solar system
by Bob Yirka , Phys.org
https://phys.org/news/2022-08-grains-astero...lder-solar.html

...some of which have been dated to 7 billion years ago. The researchers found that the dust sample held grains identical to all of the others that have been seen in meteorites, showing that it too predates the solar system.

[marsbug]

Hey all, I haven't seen this paper by JAXA's Stone Analysis Team mentioned, so I thought I'd share it - it's an interesting summary of their investigation & findings so far: Press release link (free) https://global.jaxa.jp/press/2022/09/20220923-1_e.html

Paper link (pay to view) https://www.science.org/doi/10.1126/science.abn8671

[Marcin600]

Three new articles on the Ryugu samples (and gases) published in October 2022 - free access:

On the two "extra" Ryugu particles found - 1 mm and 0.5 mm:

1. „Ryugu particles found outside the Hayabusa2 sample container”:
https://www.jstage.jst.go.jp/article/geoche...J22017/_article
https://www.jstage.jst.go.jp/article/geoche...7/_pdf/-char/en - pdf

Gas analyzes:

2. „Noble gases and nitrogen in samples of asteroid Ryugu record its volatile sources and recent surface evolution”:
https://global.jaxa.jp/press/2022/10/20221021-1_e.html
https://www.science.org/doi/10.1126/science.abo0431
https://www.science.org/doi/epdf/10.1126/science.abo0431 - pdf

3. „First asteroid gas sample delivered by the Hayabusa2 mission: A treasure box from Ryugu”:
https://global.jaxa.jp/press/2022/10/20221021-2_e.html
https://www.science.org/doi/10.1126/sciadv.abo7239
https://www.science.org/doi/epdf/10.1126/sciadv.abo7239 - pdf

[Marcin600]

New, interesting research results (in English, open access) - avalanches, and the formation of top-shaped asteroids and rubble-pile satellites
Formation of Moons and Equatorial Ridge around Top-shaped Asteroids after Surface Landslide:
https://curation.isas.jaxa.jp/en/topics/22-11-30.html
https://www.isas.jaxa.jp/home/research-port...eway/2022/1125/
https://iopscience.iop.org/article/10.3847/2041-8213/ac922d
https://iopscience.iop.org/article/10.3847/...8213/ac922d/pdf

(the research summary at the second link contains video simulations)

The research concerns not only Ryugu, but also Bennu and Didymos-Dimorphos.

[Bill Harris]

Fascinating.