Subterahertz radius and limb brightening of the Sun derived from SST and ALMA

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dc.contributor.authorMenezes F.
dc.contributor.authorSelhorst C.L.
dc.contributor.authorGimenez De Castro C.G.
dc.contributor.authorValio A.
dc.date.accessioned2024-03-12T19:15:20Z
dc.date.available2024-03-12T19:15:20Z
dc.date.issued2022
dc.description.abstract© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Measurements of the radius and limb brightening of the Sun provide important information about the solar atmosphere structure and temperature. The solar radius increases as the observation at radio frequency decreases, indicating that each emission originates higher in the atmosphere. Thus, different layers of the solar atmosphere can be probed by observing at multiple wavelengths. In this work, we determined the average radius and limb brightening at 100, 212, 230, and 405 GHz, using data from the Solar Submillimeter Telescope and Atacama Large Millimeter/submillimeter Array's single-dish observations. For the first time, limb brightening values for frequencies of 212 and 405 GHz were estimated. At sub-THz frequencies, the observed limb brightening may affect the solar radius measurements. We use two different and well-known approaches to determine the radius: The half-power method and the inflection-point method. We investigate how the antenna beam size and the limb brightening level, LB, can affect the radius measurements using both methods. Our results showed that the inflection-point method is the least affected by these parameters, and should thus be used for solar radius estimates at radio wavelengths. The measured average radii are 968 ± 3 arcsec (100 GHz), 963 ± 3 arcsec (212 GHz), 963 ± 2 arcsec (230 GHz), and 963 ± 5 arcsec (405 GHz). Finally, we used forward modelling to estimate the ranges of LB of the solar disc resulting in 5-19 per cent (100 GHz), 2-12 per cent (212 GHz), 6-18 per cent (230 GHz), and 3-17 per cent (405 GHz). Both radius and limb brightening estimates agree with previous measurements reported in the literature.
dc.description.firstpage877
dc.description.issuenumber1
dc.description.lastpage885
dc.description.volume511
dc.identifier.doi10.1093/mnras/stab3501
dc.identifier.issn1365-2966
dc.identifier.urihttps://dspace.mackenzie.br/handle/10899/34382
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.rightsAcesso Restrito
dc.subject.otherlanguagemethods: data analysis
dc.subject.otherlanguageSun: atmosphere
dc.subject.otherlanguageSun: chromosphere
dc.subject.otherlanguageSun: radio radiation
dc.titleSubterahertz radius and limb brightening of the Sun derived from SST and ALMA
dc.typeArtigo
local.scopus.citations6
local.scopus.eid2-s2.0-85138848720
local.scopus.subject100 GHz
local.scopus.subjectInflexion point
local.scopus.subjectMethods. Data analysis
local.scopus.subjectPoint methods
local.scopus.subjectRadius measurements
local.scopus.subjectSolar atmosphere
local.scopus.subjectSolar radius
local.scopus.subjectSun: atmosphere
local.scopus.subjectSun: Chromosphere
local.scopus.subjectSun: radio radiation
local.scopus.updated2024-12-01
local.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85138848720&origin=inward
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