Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission

Using data collected by the Indian Mars Orbiter Mission (MOM) in 2021 October, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is introduced to directly relate these two parameters. The study f...

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Main Authors: Keshav Aggarwal, R. K. Choudhary, Abhirup Datta, Roopa M. V., Bijoy K. Dai
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/adb627
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author Keshav Aggarwal
R. K. Choudhary
Abhirup Datta
Roopa M. V.
Bijoy K. Dai
author_facet Keshav Aggarwal
R. K. Choudhary
Abhirup Datta
Roopa M. V.
Bijoy K. Dai
author_sort Keshav Aggarwal
collection DOAJ
description Using data collected by the Indian Mars Orbiter Mission (MOM) in 2021 October, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is introduced to directly relate these two parameters. The study focuses on observations conducted from 2021 October 2 to October 14, a relatively quiet phase of solar cycle 25. The analysis targeted the coronal region within heliocentric distances of 5–8 R _⊙ , near the ecliptic plane. In this region, solar wind velocities ranged from 100 to 150 km s ^−1 , while electron densities were on the order of 10 ^10 m ^−3 . We also compared our results with electron density observations and models derived from previous studies. Though the decrease in the electron densities with respect to increasing heliocentric distance matches quite well with the theoretical models, MOM estimates fall at the lower edge of the distribution. This difference may be attributed to the prolonged weak solar activity during the MOM observations, in contrast to prior studies conducted during periods of comparatively higher solar activity in earlier solar cycles.
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publisher IOP Publishing
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series The Astrophysical Journal
spelling doaj-art-41df392476e843e294732ecc3c62e8f42025-08-20T03:40:18ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01982215210.3847/1538-4357/adb627Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter MissionKeshav Aggarwal0https://orcid.org/0000-0002-7004-8670R. K. Choudhary1https://orcid.org/0000-0002-1276-0088Abhirup Datta2https://orcid.org/0000-0002-5333-1095Roopa M. V.3Bijoy K. Dai4Department of Astronomy, Astrophysics and Space Engineering (DAASE), Indian Institute of Technology Indore , Indore, Madhya Pradesh 453552, India ; keshavagg1098@gmail.comSpace Physics Laboratory (SPL) , Indian Space Research Organization, Vikram Sarabhai Space Centre, Thiruvananthapuram, Kerala 695022, IndiaDepartment of Astronomy, Astrophysics and Space Engineering (DAASE), Indian Institute of Technology Indore , Indore, Madhya Pradesh 453552, India ; keshavagg1098@gmail.comISRO Telemetry Tracking and Command Network (ISTRAC) , Bengaluru, Karnataka 560058, IndiaISRO Telemetry Tracking and Command Network (ISTRAC) , Bengaluru, Karnataka 560058, IndiaUsing data collected by the Indian Mars Orbiter Mission (MOM) in 2021 October, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is introduced to directly relate these two parameters. The study focuses on observations conducted from 2021 October 2 to October 14, a relatively quiet phase of solar cycle 25. The analysis targeted the coronal region within heliocentric distances of 5–8 R _⊙ , near the ecliptic plane. In this region, solar wind velocities ranged from 100 to 150 km s ^−1 , while electron densities were on the order of 10 ^10 m ^−3 . We also compared our results with electron density observations and models derived from previous studies. Though the decrease in the electron densities with respect to increasing heliocentric distance matches quite well with the theoretical models, MOM estimates fall at the lower edge of the distribution. This difference may be attributed to the prolonged weak solar activity during the MOM observations, in contrast to prior studies conducted during periods of comparatively higher solar activity in earlier solar cycles.https://doi.org/10.3847/1538-4357/adb627Solar windRadio occultationSolar corona
spellingShingle Keshav Aggarwal
R. K. Choudhary
Abhirup Datta
Roopa M. V.
Bijoy K. Dai
Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
The Astrophysical Journal
Solar wind
Radio occultation
Solar corona
title Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
title_full Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
title_fullStr Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
title_full_unstemmed Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
title_short Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission
title_sort insights into solar wind flow speeds from the coronal radio occultation experiment findings from the indian mars orbiter mission
topic Solar wind
Radio occultation
Solar corona
url https://doi.org/10.3847/1538-4357/adb627
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