| Author(s) and Co-Author(s) with Affiliation: Dibyendu Misra(Physical Research Laboratory, Ahmedabad-380009, India; Indian Institute of Technology Gandhinagar, Gandhinagar-382055, India), Megha Bhatt(Physical Research Laboratory, Ahmedabad-380009, India), Christian Woehler(Image Analysis Group, Dortmund University of Technology, Otto-Hahn-Str.4, 44227 Dortmund, Germany), Shashikiran Ganesh(Physical Research Laboratory, Ahmedabad-380009, India), Anil Bhardwaj(Physical Research Laboratory, Ahmedabad-380009, India) |
| Abstract: Lunar pyroclasts are considered as one of the best proxies for constraining the primitive lunar mantle composition [1] compared to other volcanic products (e.g., mare basalts). Lunar pyroclastic deposits (LPDs) are very low albedo, smooth, homogeneous lunar lithological units widely interpreted to have formed through explosive volcanic processes, and only restricted to ~1% of the lunar surface [2]. Though extensive spectral and morphological analyses of LPDs are carried out at finer spatial resolution, understanding of their physical properties is limited [3]. In order to characterize the physical properties of LPDs, we have carried out a systematic multi-band (UBVRI) imaging polarimetric study of nearside LPDs at phase angles ~3°–124°, using PolCam mounted on the 50 cm telescope at Mount Abu observatory of Physical Research Laboratory.
The results obtained by deriving Stokes parameters, degree of linear polarization (DoLP), and the position angle for the plane of polarization provide information on the physical state of LPDs (e.g., relative grain size, roughness etc.) [4,5]. A comparative analysis of the wavelength-dependent derived key polarimetric parameters, including the minimum and maximum DoLP (Pₘᵢₙ, Pₘₐₓ), their corresponding phase angles (αₘᵢₙ, αₘₐₓ), inversion angle (αᵢₙᵥ), the slope (h) at αᵢₙᵥ [3,4,5] across different nearside LPDs, offers insights into surface modification processes and heterogeneity in lunar explosive volcanism.
Reference: [1] Delano, J. W. (1986), JGR: Solid Earth, 91 (B4), 201–213; [2] Head, J. W. (1974), LPSC, 5, 207–222; [3] Misra, D. et al. (2024), No. EPSC2024-1085. Copernicus Meetings, [4] Wöhler, C., et al., (2024), The Astronomical Journal, 167(5), 187; [5] Bhatt, M., et al. (2023), A&A, 674, A82. |
