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Browsing IIAP Publications by Title

Browsing IIAP Publications by Title

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  • The He II 5411 Å velocity curve of the Wolf-Rayet eclipsing system HD 214419 
    Giridhar, S (Indian Institute of Astrophysics, 1978)
    A velocity curve of the Wolf-Rayet eclipsing system HD 214419 is obtained from measures on prismatic spectra of the Hell 5411 emission line. The shape of the velocity curve is unlike that obtained for Hell 4686. The emission ...
  • The He II line 4686 in WN binaries 
    Shylaja, B. S (Indian Academy of Sciences, 1987-06)
    The behaviour of the λ4686 line of He II in various WN binaries is studied for variations in total flux as well as radial velocities. It appears that the true motion of the WN component is not depicted by this line especially ...
  • Head-on collision of disk-sphere galaxies 
    Namboodiri, P. M. S; Sastry, K. S; Narasimhan, K. S. V. S (2006-02)
    Numerical simulations are performed to study the tidal effects of non-merging rapid head-on collision between a disk galaxy and a spherical galaxy. The disk consists of three components – a disk, a bulge and a halo – and ...
  • Heating in intense flux tubes 
    Hasan, S. S (Springer-Verlag, 1991-01)
  • Heating of the quiet solar chromosphere. 1: Role of the inner network bright points 
    Kariyappa, R; Sivaraman, K. R; Anandaram, M. N (Springer, 1994-05)
    We have analyzed a large number of Ca II H line profiles at the sites of the bright points in the interior of the network using a 35-min-long time sequence of spectra obtained at the Vacuum Tower Telescope (VTT) of the ...
  • Heating of the Solar Corona 
    Krishan, V (Indian Institute of Astrophysics, Bangalore, 1988)
    The maintenance of the million degree solar corona continues to be a challenging and an inspiring problem. There are basically two different mechanisms of heating depending upon the dominance or otherwise of the magnetic ...
  • Height gradient of F region vertical drift in the evening equatorial ionosphere 
    Sastri, J. H; Varma, V. K. M; Nayar, S. R. P (American Geophysical Union, 1995-10)
    Simultaneous measurements of F-region vertical drift are made in the evening hours (1700-2100 IST) at Trivandrum (dip 0.6°N) and Kodaikanal (dip 4°N) on fifteen days during December 1993- January 1994 using the HF phase ...
  • Heliophysical processes 
    Gopalswamy, N (editor); Hasan, S. S (editor); Ambastha, A (editor) (Springer-Verlag, 2010)
    An outgrowth of the first Asia-Pacific Regional School on the International Heliophysical Year (IHY), this volume contains a collection of review articles describing the universal physical processes in the heliospace ...
  • Helioseismic inversion to infer the depth profile of solar meridional flow using spherical born kernels 
    Mandal, K; Hanasoge, S. M; Rajaguru, S. P; Antia, H. M (IOP Publishing, 2018-08)
    Accurate inferences of solar meridional flow are crucial for understanding solar dynamo processes. Wave travel times, as measured on the surface, will change if the waves encounter perturbations, e.g., in the sound speed ...
  • Helioseismology 
    Antia, H. M (Indian Institute of Astrophysics, Bangalore, 1988)
    Many of the oscillations observed at the solar surface have been identified with resonant normal modes of the entire solar body. Accurate measurements of frequencies of these modes enable us to study the internal structure ...
  • Helium Enhancement in the Metal-rich Red Giants of ω Centauri 
    Hema, B. P; Pandey, G; Kurucz, R. L; Prieto, C. A (IOP Publishing, 2020-07-01)
    The helium-enriched (He-enriched) metal-rich red giants of ω Centauri, discovered by Hema & Pandey using the low-resolution spectra from the Vainu Bappu Telescope, and confirmed by the analyses of the high-resolution spectra ...
  • Helmholtz Resonance Cell for Gas Phase Photoacoustic Studies 
    Ajith Prasad, K. C; Nampoori, V. P. N; Vallabhan, C. P. G (Indian Institute of Astrophysics, Bangalore, 1991)
    The design and frabication of a Helmholtz type gas phase photoacoustic cell are described. The cell which incorporates a miniature microphone (Knowles B.T.1759) along with a matching pre-amplifier is very sensitive and can ...
  • Hemispheric asymmetry of sunspot area in solar cycle 23 and rising phase of solar cycle 24: comparison of three data sets 
    Ravindra, B; Javaraiah, J (2015-08)
    Analysis of long-term solar data from different observatories is required to compare and confirm the various level of solar activity in depth. In this paper, we study the north–south asymmetry of monthly mean sunspot area ...
  • HF doppler and ionosonde observations on the onset conditions of equatorial spread F 
    Jayachandran, B; Balan, N; Rao, P. B; Sastri, J. H; Bailey, G. J (American Geophysical Union, 1993)
    The relative importance of height, vertical drift velocity, and electron density gradient of the postsunset bottomside (5.5 MHz) equatorial F region for the onset of spread F is studied using simultaneous HF Doppler radar ...
  • HF Doppler observations of small scale plasma motions in the equatorial electrojet 
    Sastri, J. H; Ramesh, K. B; Rao, J. V. S. V; Rao, D. R. K (The Royal Swedish Academy of Sciences, 1986-12)
    Recordings of the variations in phase path, P of reflections, at vertical incidence, from blanketing sporadic-E layers over Kodaikanal (dip 3.5°N) revealed small amplitude, quasi-sinusoidal oscillations of 45-180 s periods ...
  • HI line analysis of Herbig Ae/Be stars using X-Shooter spectra 
    Shridharan, B; Mathew, Blesson; Arun, R; Cysil, T. B (Indian Academy of Sciences, 2023-12)
    Herbig Ae/Be stars are intermediate-mass pre-main sequence stars undergoing accretion through their circumstellar disk. The optical and infrared (IR) spectra of HAeBe stars show Hi emission lines belonging to Balmer, ...
  • Hi-C 2.1 Observations of Reconnection Nanojets 
    Patel, Ritesh; Pant, V (American Astronomical Society, 2022-10-20)
    One of the possible mechanisms for heating the solar atmosphere is the magnetic reconnection occurring at different spatiotemporal scales. The discovery of fast bursty nanojets due to reconnection in the coronal loops has ...
  • Hidden in plain sight: UVIT and MUSE discovery of a large, diffuse star-forming galaxy 
    Yadav, Jyoti; Mousumi Das; Barway, Sudhanshu; Combes, Francoise (EDP Sciences, 2022-01)
    We report the discovery of a nearby large, diffuse galaxy that shows star formation using Ultra Violet Imaging Telescope (UVIT) far-UV observations and archival optical data from Multi-Unit Spectroscopic Explorer (MUSE), ...
  • Higgs boson 
    Sivaram, C (Indian Academy of Sciences, 2012-10-25)
  • High abnormal rotation rates of sunspots and flare productivity 
    Suryanarayana, G. S (Elsevier, 2010-03)
    Solar activity, such as flares and CMEs, affect the interplanetary medium, and Earth’s atmosphere. Therefore, to understand the Space Weather, we need to understand the mechanisms of solar activity. Towards this end, we ...

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