Relationship between radar cross section and optical magnitude based on radar and optical simultaneous observations of faint meteors. (December 2020)

• Record Type: Journal Article
• Authors: Ohsawa, Ryou; Hirota, Akira; Morita, Kohei; Abe, Shinsuke; Kastinen, Daniel; Kero, Johan; Szasz, Csilla; Fujiwara, Yasunori; Nakamura, Takuji; Nishimura, Koji; Sako, Shigeyuki; Watanabe, Jun-ichi; Aoki, Tsutomu; Arima, Noriaki; Arimatsu, Ko; Doi, Mamoru; Ichiki, Makoto; Ikeda, Shiro; Ita, Yoshifusa; Kasuga, Toshihiro; Kobayashi, Naoto; Kokubo, Mitsuru; Konishi, Masahiro; Maehara, Hiroyuki; Miyata, Takashi; Mori, Yuki; Morii, Mikio; Morokuma, Tomoki; Motohara, Kentaro; Nakada, Yoshikazu; Okumura, Shin-ichiro; Sarugaku, Yuki; Sato, Mikiya; Shigeyama, Toshikazu; Soyano, Takao; Takahashi, Hidenori; Tanaka, Masaomi; Tarusawa, Ken'ichi; Tominaga, Nozomu; Urakawa, Seitaro; Usui, Fumihiko; Yamashita, Takuya; Yoshikawa, Makoto;
• Is Part Of: Planetary and space science. Volume 194(2020)
• Publication Date: 2020-12
• Subjects: meteors -- Meteoroids -- Interplanetary medium; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2020.105011
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: Radar and optical simultaneous observations of meteors are important to understand the size distribution of the interplanetary dust. However, faint meteors detected by high power large aperture radar observations, which are typically as faint as 10 mag. In optical, have not been detected until recently in optical observations, mainly due to insufficient sensitivity of the optical observations. In this paper, two radar and optical simultaneous observations were organized. The first observation was carried out in 2009–2010 using Middle and Upper Atmosphere Radar (MU radar) and an image-intensified CCD camera. The second observation was carried out in 2018 using the MU radar and a mosaic CMOS camera, Tomo-e Gozen, mounted on the 1.05-m Kiso Schmidt Telescope. In total, 331 simultaneous meteors were detected. The relationship between radar cross sections and optical V -band magnitudes was well approximated by a linear function. A transformation function from the radar cross section to the V -band magnitude was derived for sporadic meteors. The transformation function was applied to about 150, 000 meteors detected by the MU radar in 2009–2015, large part of which are sporadic, and a luminosity function was derived in the magnitude range of −1.5–9.5 mag. The luminosity function was well approximated by a single power-law function with the population index of r = 3.52 ± 0.12 . The present observation indicates that the MU radar has capability to detect interplanetary dust of 10 − 5 – 10 0 g in mass as meteors. Highlights: In total, 331 meteors were detected simultaneously by radar and optically. A correlation between the radar cross section and the optical magnitude is firmly confirmed. The mass range of the meteor detected by MU radar is constrained to about 10 5 −10 0 ​g.