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- Geem, Jooyeon, et al.
(author)
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Spectral type and geometric albedo of (98943) 2001 CC21, the Hayabusa2# mission target
- 2023
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In: Monthly Notices of the Royal Astronomical Society: Letters. - : Oxford University Press. - 1745-3925 .- 1745-3933. ; 525:1, s. L17-L21
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Journal article (peer-reviewed)abstract
- We conducted optical polarimetry and near-infrared spectroscopy of Japan Aerospace Exploration Agency (JAXA)'s Hayabusa2# mission target, (98943) 2001 CC21, in early 2023. Our new observations indicate that this asteroid has a polarimetric inversion angle of ∼20°, absorption bands around 0.9 and 1.9 μm, and a geometric albedo of 0.23 ± 0.04. All these features are consistent with those of S types but inconsistent with L types. Based on this evidence, we conclude that JAXA's Hayabusa2# spacecraft will explore an S-type asteroid (more specifically, an L or LL chondrite-like object) with albedo and size (0.44-0.53 km when we assume the absolute magnitude of 18.8) similar to (25143) Itokawa.
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| 2. |
- Ishiguro, Masateru, et al.
(author)
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Polarimetric properties of the near-Sun asteroid (155140) 2005 UD in comparison with other asteroids and meteoritic samples
- 2022
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 509:3, s. 4128-4142
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Journal article (peer-reviewed)abstract
- The investigation of asteroids near the Sun is important for understanding the final evolutionary stage of primitive Solar system objects. A near-Sun asteroid (NSA), (155140) 2005 UD, has orbital elements similar to those of (3200) Phaethon (the target asteroid for the JAXA’s DESTINY+ mission). We conducted photometric and polarimetric observations of 2005 UD and found that this asteroid exhibits a polarization phase curve similar to that of Phaethon over a wide range of observed solar phase angles (α = 20–105°) but different from those of (101955) Bennu and (162173) Ryugu (asteroids composed of hydrated carbonaceous materials). At a low phase angle (α ≲ 30°), the polarimetric properties of these NSAs (2005 UD and Phaethon) are consistent with anhydrous carbonaceous chondrites, while the properties of Bennu are consistent with hydrous carbonaceous chondrites. We derived the geometric albedo, pV ∼ 0.1 (in the range of 0.088–0.109); mean V-band absolute magnitude, HV = 17.54 ± 0.02; synodic rotational period, Trot=5.2388±0.0022h (the two-peaked solution is assumed); and effective mean diameter, Deff=1.32±0.06km. At large phase angles (α ≳ 80°), the polarization phase curve are likely explained by the dominance of large grains and the paucity of small micron-sized grains. We conclude that the polarimetric similarity of these NSAs can be attributed to the intense solar heating of carbonaceous materials around their perihelia, where large anhydrous particles with small porosity could be produced by sintering.
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| 3. |
- Oskolkov, Nikolay, et al.
(author)
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High-throughput muscle fiber typing from RNA sequencing data
- 2022
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In: Skeletal Muscle. - : Springer Science and Business Media LLC. - 2044-5040. ; 12, s. 1-9
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Journal article (peer-reviewed)abstract
- Background: Skeletal muscle fiber type distribution has implications for human health, muscle function, and performance. This knowledge has been gathered using labor-intensive and costly methodology that limited these studies. Here, we present a method based on muscle tissue RNA sequencing data (totRNAseq) to estimate the distribution of skeletal muscle fiber types from frozen human samples, allowing for a larger number of individuals to be tested. Methods: By using single-nuclei RNA sequencing (snRNAseq) data as a reference, cluster expression signatures were produced by averaging gene expression of cluster gene markers and then applying these to totRNAseq data and inferring muscle fiber nuclei type via linear matrix decomposition. This estimate was then compared with fiber type distribution measured by ATPase staining or myosin heavy chain protein isoform distribution of 62 muscle samples in two independent cohorts (n = 39 and 22). Results: The correlation between the sequencing-based method and the other two were rATPas = 0.44 [0.13–0.67], [95% CI], and rmyosin = 0.83 [0.61–0.93], with p = 5.70 × 10–3 and 2.00 × 10–6, respectively. The deconvolution inference of fiber type composition was accurate even for very low totRNAseq sequencing depths, i.e., down to an average of ~ 10,000 paired-end reads. Conclusions: This new method (https://github.com/OlaHanssonLab/PredictFiberType) consequently allows for measurement of fiber type distribution of a larger number of samples using totRNAseq in a cost and labor-efficient way. It is now feasible to study the association between fiber type distribution and e.g. health outcomes in large well-powered studies.
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