Artificial Meteor and Chelyabinsk Ablation Test using Arc-heated Wind Tunnel

Transcription

1 Artificial Meteor and Chelyabinsk Ablation Test using Arc-heated Wind Tunnel Shinsuke ABE Nihon University, Dept. Aerospace Engineering Collaborators; K. Araki, T. Iwasaki, K. Toen (Nihon Univ.) Hironori Sahara (Tokyo Metropolitan Univ.) Takeo Watanabe (Teikyo Univ.) Lena Okajima (ALE Co. Ltd.,)

2 S. Abe et al Hayabusa spacecraft Capsule Explosion 62.7 km; numerous strong emissions were seen in the visible spectrum. Exotic lines; CuI (5700 and 5782!! ), Zn I lines (4680, 4722, and 4811! ), MoI (5506 and 5533!!), XeI (4624 and 4671!)

3 Hayabusa spacecraft & capsule The maximum absolute magnitude of the fireball of was reached at a height of 67 km The dynamic pressures acting on the spacecraft at the fragmentation points were only 1 50 kpa No spacecraft fragment was seen to survive below a height of 47 km The integral luminous efficiency of the spacecraft was 1.3% and the capsule was 0.03% Borovická, Abe, Shrben!, Spurn!, Bland, 2011

4 To understand ablation processes of atmospheric entry, artificial meteor test is carried out using JAXA s facility.

5 Strength of Meteoroids by MU Radar Meteor head-echo very weak Geminids 3200 Phaethon Perseids 109P/Swift-Tuttle very strong Geminids; not depending on size S. Abe, J. Kero, T. Nakamura et al. (in prep)

6 High speed camera Phantom v711 JAXA/ISAS Arc-heated Wind Tunnel Spectroradiometer & Spectrograph OceanOptics QEPro, HR4000CG-UV-NIR

7 Chelyabinsk Meteorite ; 2013/2/15

8 Chelyabinsk samples light and dark lithology in the cm scale. (W); Light (White) sample (B); Dark (Black) sample T. Arai, S. Abe et al. LPI (2014) 2860.

9 Artificial Meteor Test using JAXA Arc-heated wind tunnel

10 Chelyabinsk (LL5) UV-VIS Spectrum (1/30s)

11 Fe+Mg+Al+C (FMAC) with Sabo UV-VIS Spectrum (1/30s)

12 Blackbody is dominant for low-velocity meteors

13 Chelyabinsk Differential ablation (Na early release)

14 FMAC Differential ablation

15 FMAC High speed imaging (exp=10!s, 1000 fps)

16 Chelyabinsk High speed imaging (exp=10!s, 1000 fps)

17 Mass Loss Rate, dm/dt Y-axis Rest of mass [%] X-axis Time [s] type1 type2 type

18 1000 Fragmentation N=a"L 100 Cumulative number of fragments 10 Ko#ice $=1.53 Sutter s Mill $=1.51 Bassikounou $=1.32 (V. Vinnikov et.al 2014) Integrated Luminosity

19 Fe+Mg+Al+C (FMAC) Maximum compressive stress as a function of Porosity (ultimate strength ) Compressive Stress [MPa] stress-strain diagram y = x Porosity [%]

20 (Vojacek, V., et al., 2015) ground velocity Draconids Orionids Geminids Quadrantids! Lyrids Perseids! Taurids Leonids! Capricornids Aqua Fe I[386nm] Fe I-15 Draconids Orionids Geminids Quadrantids! Lyrids Perseids! Taurids Leonids! Capricornids Aqua! Perseids Geminids! Sporadic LL5! CM2 olivine Fe+Mg FMAC1 FMAC1 FMAC2 This study Aqua Perseids Geminids Sporadic LL5 CM2 Olivine olivine Fe+Mg FMAC1 FMAC1! FMAC2!! Mg I-2 Na I-1

21 Fe I[386nm] Fe I-15 Comparison between Artificial meteor and Geminids FMAC1(29.2%) FMAC1(17.7%) FMAC2(44.4%) Geminids Time evolution of Na/Mg/Fe ratio Color changes with time. ending ending beginning beginning ending beginning Mg I-2 Na I-1

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23 Thank You On-demand Meteor Shower First test in 2018

24 Chelyabinsk LL5(6.0%) Jbilet Winselwan CM2 CM2(23.0%) あa Olivine オリビン(13.7%) NaⅠ[818nm] [819nm] [770nm] 35 [K] KⅠ[766nm] 31 [K] NaⅠ[589nm] CrⅠ[520nm] Jbilet Winselwan(CM2) 1.0E CM2 g(x) おおおお おおおお CrⅠ[425nm] [427nm] [429nm] -2-1 Flux [µ W cm nm ] 1.0E-09 Chelyabinsk LL5(6.0%) T = 2473 オリビン(13.7%) T = 2442 Olivine CrⅠ[358nm] FeⅠ[373nm] FeⅠ[386nm] 1.0E-08 intensity [a.u.] 1 黒体放射温度 0.1 T = E [K] Wavelength [nm] Wavelength [nm]

25 Differential ablation (Na early release) signature of structure & volatility of meteoroids S. Abe (2009), Meteoroids and Meteors - observations and connection to parent bodies, Springer

26 CFD simulation of HAYABUSA capsule Vibration-rotation temperature of ~13,000 K for and CN is reasonable. Fujita, Abe et al. (2013)

27 The vibration temperature of molecular was dramatically changed from 4, km to 13, km. The observed spectra are a superposition of the post shock plasma radiation which is mixed with a shock layer heating and downward plasma. Thus, it is logical to understand that the high temperature region was induced by a shock layer of the spacecraft which rapidly grew between 92.5 km and 82.9 km in height. bands originated from the spacecraft was much stronger than CN bands originated from the capsule in which Carbon was the major erosion product of the Carbon-Phenol heat shield of the capsule as seen by the Stardust capsule (Jenniskens 2010; Winter & Trumble 2011). Capsule Spacecraft + Capsule

28 Discovery of Molecular Bands in Leonid Fireball(-5 mag.) Atoms + N + 2 +OH N 2 + was expected for the SRC emission. Atom;4500K N 2+ ;10000K Bow shock neck recompression shock thermochemical non-equilibrium state wake core N 2 + (1,0) Shock layer backward flow Mg I + OH N 2 + (2,0) N 2 + (0,1) N 2 + (0,0) Abe, et al. ApJ 618, L141-L144, 2005.

29 theoretical gain pattern Kyoto University, RISH Middle and Upper Atmosphere Radar Observed number of meteors, normalized by beam area, versus RCS (Radar Cross Section) and radial distance from beam centre. >150k meteoroids were detected during ,000-4,000 meteor head echoes / day Data rate ~ 20GB/hour average! of velocity ~ 0.25 km/s average! of perihelion = AU