Reflectivity of Venus’s dayside disk during the 2020 observation campaign: outcomes and future perspectives - Archive ouverte HAL Access content directly
Journal Articles The Planetary Science Journal Year : 2022

## Reflectivity of Venus’s dayside disk during the 2020 observation campaign: outcomes and future perspectives

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Yeon Joo Lee
Antonio García Muñoz
Atsushi Yamazaki
Eric Quémerais
Stefano Mottola
Stephan Hellmich
Thomas Granzer
• Function : Author
Martin Roth
Eulalia Gallego-Cano
Jean-Yves Chaufray
Rozenn Robidel
• Function : Author
• PersonId : 1156176
Go Murakami
• Function : Author
Kei Masunaga
Murat Kaplan
• Function : Author
Orhan Erece
• Function : Author
Ricardo Hueso
Petr Kabáth
Agustín Sánchez-Lavega
Myung-Jin Kim
Valeria Mangano
Kandis-Lea Jessup
• Function : Author
Ko-Ichiro Sugiyama
• Function : Author
Shigeto Watanabe
Takehiko Satoh
Masato Nakamura
• Function : Author
Masataka Imai
Juan Cabrera

#### Abstract

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 SO$_2$ 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.

#### Domains

Sciences of the Universe [physics]

### Dates and versions

insu-03780953 , version 1 (19-09-2022)

### Identifiers

• HAL Id : insu-03780953 , version 1
• DOI :

### Cite

Yeon Joo Lee, Antonio García Muñoz, Atsushi Yamazaki, Eric Quémerais, Stefano Mottola, et al.. Reflectivity of Venus’s dayside disk during the 2020 observation campaign: outcomes and future perspectives. The Planetary Science Journal, 2022, 3, pp.209. ⟨10.3847/psj/ac84d1⟩. ⟨insu-03780953⟩

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