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Habikino, Japan

Suzuki H.,Rikkyo University | Nakamura T.,Japan National Institute of Polar Research | Vadas S.L.,NorthWest Research Associates, Inc. | Tsutsumi M.,Japan National Institute of Polar Research | And 2 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2013

A fireball meteor with a visual magnitude over -6 followed by a persistent train was observed by two all-sky cameras for detecting the aurora and sodium airglow at Syowa Station (69.0°S, 39.5°E), Antarctica, on 7 June 2008. The orbit and other parameters of the fireball were estimated with an all-sky television camera for detecting the aurora. After the passage of this fireball, a circular train in the Na airglow was observed. This train expanded to a diameter of about 50 km in 9 min. Assuming that the fireball contained and emitted Na, we found this ring to span the altitudes of z = 76 to 87 km. The ring's mean motion was most likely caused by a large-scale, inertia-gravity wave with a vertical wavelength of ~16 km and an amplitude of ~30 m/s in the mesopause region. ©2013. American Geophysical Union. All Rights Reserved. Source

Kero J.,Umea University | Fujiwara Y.,Nippon Meteor Society | Abo M.,Tokyo Metroplitan University | Szasz C.,Swedish Institute of Space Physics | Nakamura T.,Japan National Institute of Polar Research
Monthly Notices of the Royal Astronomical Society | Year: 2012

On 2011 October 8, the Earth passed through a stream of dust ejected by the comet 21P/Giacobini-Zinner during its perihelion passage of the year 1900, causing an outburst of October Draconid meteors. 13 Draconids were observed among ~6300 meteor head echoes with precisely determined orbits during an observational campaign ranging from October 8 05:00 ut to October 9 13:00 ut with the Shigaraki middle and upper atmosphere (MU) radar in Japan (34°85N and 136°10E). The meteor outburst occurred while the Draconid radiant was descending below and 2h later rising up above the horizon. Therefore, 11 of the detections were from very low (<15°) elevation. The detection altitudes of the Draconids were high compared to sporadic meteors of the same velocity and radiant elevation. The weighted mean geocentric velocity of the 13 Draconids was 20.6 ± 0.4kms -1, and the weighted mean radiant located at right ascension α = 263°3 ± 0°6 and declination δ = 55°8 ± 0°2. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS. Source

Fujita K.,Japan Aerospace Exploration Agency | Yamamoto M.-Y.,Kochi University of Technology | Abe S.,National Central University | IShihara Y.,Japan National Astronomical Observatory | And 12 more authors.
Publications of the Astronomical Society of Japan | Year: 2011

On 2010 June 13, the HAYABUSA asteroid explorer returned to Earth and underwent a super-orbital atmospheric reentry. In order to recover the sample return capsule and to take ground-based measurements, the Japan Aerospace Exploration Agency organized a ground-observation team and performed optical tracking of the capsule, spectroscopy of the fireball, and measurements of infrasounds and shock waves generated by the fireball. In this article, an overview of the ground-based observation is presented, and an outline of the preliminary results derived from observations is reported. © 2011. Astronomical Society of Japan. Source

Ueda M.,Nippon Meteor Society | Shiba Y.,Nippon Meteor Society | Yamamoto M.-Y.,Kochi University of Technology | Fujita K.,Japan Aerospace Exploration Agency | And 8 more authors.
Publications of the Astronomical Society of Japan | Year: 2011

The asteroid explorer HAYABUSA reentered into the Earth's atmosphere on 2010 June 13. We made simultaneous TV (television) observations at seven ground sites in order to calculate the trajectories of HAYABUSA and its sample return capsule (SRC), which both reentered into the atmosphere. Our TV observations showed that, after HAYABUSA reentered the atmosphere, the beginning time of its light emission on video was 13:51:57.4 UT at a height of 101.0±0.2 km. The end time was 13:52:42.0 UT at a height of 38.6±0.2 km. The initial velocity at the beginning was 12.1±0.3 kms1, and the entry angle was 9°. After identifying SRC as separated light emission independent of the mother spacecraft, we analyzed the trajectory of SRC from a height of 52.9 km to 35.7 km based on video images. The actual trajectory of the capsule, determined from the TV observations, was almost the same as the predicted trajectory in terms of the position, velocity, and time. We then calculated the fall spots of the SRC heat shields from the multisite TV observations. © 2011. Astronomical Society of Japan. Source

Abe S.,National Central University | Fujita K.,Japan Aerospace Exploration Agency | Kakinami Y.,Hokkaido University | Iiyama O.,Osaka Science Museum | And 5 more authors.
Publications of the Astronomical Society of Japan | Year: 2011

HAYABUSA is the first spacecraft ever to land on and lift off from any celestial body other than the moon. The mission, which returned asteroid samples to the Earth while overcoming various technical hurdles, ended on 2010 June 13, with the planned atmospheric re-entry. In order to safely deliver the sample return capsule, the HAYABUSA spacecraft ended its 7-year journey in a brilliant "artificial fireball" over the Australian desert. Spectroscopic observation was carried out in the near-ultraviolet and visible wavelengths between 3000 A° and 7500 A° at 3-20 A° resolution. Approximately 100 atomic lines such as Fe I, MgI, NaI, Al I, Cr I, MnI, Ni I, Ti I, Li I, ZnI, OI, and NI were identified from the spacecraft. Exotic atoms such as Cu I, MoI, XeI and Hg I were also detected. A strong Li I line (6708 A°) at a height of ̃55 km originated from the onboard Li-Ion batteries. The FeO molecule bands at a height of ̃63 km were probably formed in the wake of the spacecraft. The effective excitation temperature as determined from the atomic lines varied from 4500K to 6000K. The observed number density of Fe I was about 10 times more abundant than MgI after the spacecraft explosion. N+ 2 (1μ) bands from a shock layer and CN violet bands from the sample return capsule's ablating heat shield were dominant molecular bands in the near-ultraviolet region of 3000- 4000 A°.OH(A-X) band was likely to exist around 3092 A°. A strong shock layer from the HAYABUSA spacecraft was rapidly formed at heights between 93 km and 83 km, which was confirmed by detection of N+ 2 (1μ) bands with a vibration temperature of ̃13000K. Gray-body temperature of the capsule at a height of ̃42 km was estimated to be ̃2437K which is matched to a theoretical prediction. The final message of the HAYABUSA spacecraft and its sample return capsule are discussed through our spectroscopy. © 2011. Astronomical Society of Japan. Source

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