Reflectivity of Venus's Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives

• Authors: LEE Yeon Joo; MUNOZ Antonio Garcia; YAMAZAKI Atsushi; QUEMERAIS Eric; MOTTOLA Stefano; HELLMICH Stephan; GRANZER Thomas; BERGOND Gilles; ROTH Martin; GALLEGO-CANO Eulalia; CHAUFRAY Jean-Yves; ROBIDEL Rozenn; MURAKAMI Go; MASUNAGA Kei; KAPLAN Murat; ERECE Orhan; HUESO Ricardo; KABÁTH Petr; ŠPOKOVÁ Magdalena; SANCHEZ-LAVEGA Agustin; KIM Myung-Jin; MANGANO Valeria; JESSUP Kandis-Lea; WIDEMANN Thomas; SUGIYAMA Ko-ichiro; WATANABE Shigeto; YAMADA Manabu; SATOH Takehiko; NAKAMURA Masato; IMAI Masataka; CABRERA Juan
• Year of publication: 2022
• Type: Article in Periodical
• Magazine / Source: Planetary Science Journal
• MU Faculty or unit: Faculty of Science

Web

• https://arxiv.org/pdf/2207.13495.pdf
• https://iopscience.iop.org/article/10.3847/PSJ/ac84d1

• Doi: http://dx.doi.org/10.3847/PSJ/ac84d1
• Keywords: Solar system astronomy; Planetary science; Planetary atmospheres; Atmospheric clouds; Venus; Observational astronomy
• Description: We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in 2020 August and September. The primary goal of the campaign was to investigate the absorption properties of the unknown absorber in the clouds. The secondary goal was to extract a disk mean SO2 gas abundance, whose absorption spectral feature is entangled with that of the unknown absorber at ultraviolet wavelengths. A total of three spacecraft and six ground-based telescopes participated in this campaign, covering the 52–1700 nm wavelength range. After careful evaluation of the observational data, we focused on the data sets acquired by four facilities. We accomplished our primary goal by analyzing the reflectivity spectrum of the Venus disk over the 283–800 nm wavelengths. Considerable absorption is present in the 350–450 nm range, for which we retrieved the corresponding optical depth of the unknown absorber. The result shows the consistent wavelength dependence of the relative optical depth with that at low latitudes, during the Venus flyby by MESSENGER in 2007, which was expected because the overall disk reflectivity is dominated by low latitudes. Last, we summarize the experience that we obtained during this first campaign, which should enable us to accomplish our second goal in future campaigns.