[P-CG38_1AM2] Planetary atmosphere, ionosphere and magnetosphere

[PCG38-11] Millimeter Wave Band Monitoring of Venusian and Martian Middle Atmosphere with SPART Telescope

*Hiroyuki MAEZAWA¹, Yoshinori IKEDA¹, Shigeki OSAKI¹, Kouske HORIUCHI¹, Ryosuke KIRIDOSHI¹, Naruaki TANEKURA¹, Hideo SAGAWA², Atsushi NISHIMURA¹, Toshikazu OHNISHI¹, Munetoshi TOKUMARU³, Syusaki KONDOU³, Akira MIZUNO³, Tomio KANZAWA⁴, Kazuyuki HANDA⁴, Hiroyuki IWASHITA⁴, Jun MAEKAWA⁴, Masaaki OYA⁴, Nario KUNO⁴ (1.Osaka Prefecture University, 2.NiCT, 3.STEL Nagoya University, 4.Nobeyama Radio Observatory)

Keywords:planet, solar activity, radio telescope, heterodyne spectroscopy, middle atmosphere, remote sensing

To understand the influences of the activities of the central star on the middle atmospheres of the surrounding terrestrial planets, we have performed millimeter-wave-band monitoring of the atmospheres of Venus and Mars by using a 10-m radio telescope called SPART (solar planetary atmosphere research telescope). The telescope employs highly sensitive superconducting SIS mixer receivers in the 100- and 200-GHz bands for the front-end and a commercially available FFT spectrometer (1-GHz bandwidth and 67-kHz resolution) for the back-end. Millimeter-wave-band heterodyne sensing is a powerful technique that can be utilized to trace the abundance and vertical distribution of minor constituents in a planetary middle atmosphere. In 2011, we began observations of the middle atmospheres of Venus and Mars in the 100-GHz band. In 2012, the telescope had problems with the azimuth gear, motor, and synchro-to-digital converter unit, which resulted in a pause in telescope operation. In 2013, we repaired these problems and resumed the substantive operation test. We are currently restarting double-band full remote monitoring of the spectral lines of minor constituents such as ¹²CO J=2-1 at 230 GHz, ¹³CO J=2-1 at 220 GHz, and ¹²CO J=1-0 at 115 GHz toward Venus and Mars. This season, the apparent diameter of Venus is greater than the beam size at the 200-GHz band (35 arcsec.). We adopted position switching and on-the-fly modes for 100- and 200-GHz-band observations, respectively. The latter two-dimensional mapping allows us to cover the entire disk of Venus. The retrieved CO abundance variation is compared with the data of high-energy particles, X-rays, solar wind velocity/density, and other measured parameters. The data are associated with flare, coronal mass ejection, and solar proton events. In this conference, the current status of the SPART project and the millimeter-wave-band monitoring will be presented.