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ARTICLES | IIA

An international team of solar physicists has unveiled new insights into the dynamic "inner weather" of the Sun—plasma currents just beneath its surface that pulse in step with its 11-year sunspot cycle. In a study published on the 22nd of April 2025,  in the The Astrophysical Journal Letters, researchers from the Indian Institute of Astrophysics (IIA), Stanford University (USA), and the National Solar Observatory (NSO, USA) have traced how these hidden flows shift over time, potentially reshaping our understanding of how the Sun's interior connects to its outer magnetic behavior, which has far-reaching influence on space weather and Earth.

This is based on the paper titled "Solar Cycle Variations in Meridional Flows and Rotational Shear within the Sun's Near-surface Shear Layer", by Anisha Sen, S. P. Rajaguru, Abhinav Govindan Iyer, Ruizhu Chen, Junwei Zhao, and Shukur Kholikov, 2025, Astrophysical Journal Letters, 984, 1.

Press release by PIB published here.

Press release issued by DST here.

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Since Helium does not produce any observable spectral lines from the visible surface, or the photosphere, of the Sun, its abundance has usually been estimated through indirect means. In a recent study, the abundance of Helium in our Sun has been estimated accurately using the Magnesium and Carbon features in the observed high-resolution spectrum of the Sun.

This is based on the paper titled "Helium Abundance of the Sun: A Spectroscopic Analysis", by Satyajeet Moharana, B. P. Hema, and Gajendra Pandey, 2024, Astrophysical Journal, 974, 2.

Press release by PIB published here.

Press release issued by DST here.

Download the paper from here.

The galaxy NGC 1052-DF2 has remained a puzzle for astronomers, since modeling has shown that it is deficient in dark matter, which is in conflict with the standard galaxy formation and evolution models. A recent work from IIA shows that the estimation of the dark matter halo is critically dependent on the shape and structure of the dark matter halo and anisotropy of the stellar dispersion.

This is based on the paper titled "Challenges in modeling the dark matter halo of NGC 1052–DF2: Cored versus cuspy halo models", by K. Aditya, 2024, Astronomy and Astrophysics, Letters, 984, 1.

Press release issued by DST here.

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A new study has accurately estimated the physical parameters of thermal and magnetic field structures of solar coronal holes which have significant influence on space weather. They found that there is no latitudinal variation of temperature structure of coronal holes, suggesting that coronal holes are likely to originate from the deep interior, and also that there is a latitudinal variation of strength of magnetic field structure of coronal holes that increases from the solar equator to the pole suggesting that coronal holes might have formed from the superposition of Alfven wave perturbations.

This is based on the paper titled "Thermal and magnetic field structure of near-equatorial coronal holes", by Hegde, M. and K.M. Hiremath, 688, A35, 2024, Astronomy & Astrophysics, 279, 7.

Press release by PIB published here.

Press release issued by DST here.

Download the paper from here.

More than 200 solar physicists from India and abroad have come together in Bengaluru this week for an international conference on “Sun, Space Weather, and Solar-Stellar Connections”. The conference is being organised by the Indian Institute of Astrophysics to commemorate the 125th anniversary of the Kodaikanal Solar Observatory and the birth of solar astrophysics in the country (conference webpage)

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A study led by astronomers at the Indian Institute of Astrophysics has detected the Fe K spectral lines of ionized Iron atoms from the well-known binary Active Galactic Nucleus system 4C+37.11 using data from the Chandra Space Telescope. This is the first such detection from a binary black hole system, and they were able to conclude that this emission arises from both the accretion disk and the collisionally ionized plasma surrounding the pair of supermassive black holes in this object.

This is based on the recently published paper titled "Detection of the Fe K lines from the binary AGN in 4C+37.11", by Mondal et al, 2024, Astronomy & Astrophysics, 279, 7.

Press release by PIB published here.

Press release issued by DST here.

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When astronomers from the Indian Institute of Astrophysics and their collaborators looked carefully at the galaxy NGC 3785, they found that not only does it have the longest tidal tail discovered so far, but that an ultra-diffuse galaxy is currently being formed at the end of this tidal tail as well. 

This is based on the recently published paper titled "A Tale of NGC 3785: The formation of an ultra-diffuse galaxy at the end of the longest tidal tail", by Watts et al, 2024, Astronomy & Astrophysics, 691, L13.

Press release by PIB published here.

Press release issued by DST here.

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The Indian Astronomical Observatory at Hanle, Ladakh celebrated the first day of the year 2025 by witnessing an aurorae yet again. An energetic CME that left the Sun on 29th December 2024 caused an intense geomagnetic storm on 1st January 2025. The aurora that resulted from this storm was captured as a video by the all-sky camera at Hanle. The low frequency radio emission from the CME was also observed and imaged at Gauribidanur Radio Observatory (GRO), and the Active Region behind this storm was imaged at Kodaikanal Solar Observatory. All three observatories are operated by IIA.

The Indian Institute of Astrophysics (IIA) signed a Memorandum of Understanding today with the Rural Development and Panchayat Raj (RDPR) Department of the Government of Karnataka to promote astronomy through the 5880 Arivu Kendras across the state.

Careful modelling of the thermal and ionization structure of a notable Planetary Nebula PN IC 2003, enabled astronomers from IIA to explain the observed multi-wavelength data much better than was possible by earlier researchers. IC 2003 is one of those rare Planetary Nebulae which has a hydrogen-deficient central remnant star of Wolf Rayet type. The astronomers used data from the Vainu Bappu Telescope in Kavalur, Tamil Nadu, which is operated by IIA, as well as data from other space telescopes.

This is based on the recently published paper titled "Photo-ionization structures of Planetary Nebula IC 2003 with [WR] central star", by Khushbu K. and C. Muthumariappan 2024, Advances in Space Research, 74, 3.

Press release by PIB published here.

Press release issued by DST here.

Download the paper from here.