Search Publications

Solar rotation rate from minimum to maximum of activity cycle

Kumar, Brajesh; Tripathy, S. C.; Jain, Kiran +1 more

Using helioseismic data from SOI/MDI and GONG for the current solar cycle 23, from solar minimum to near maximum phase, we report here on the temporal variation of the rotation rate.

A new look at the OB associations and star clusters in the Puppis-Vela region using HIPPARCOS data

Subramaniam, Annapurni; Bhatt, H. C.

Sumer/soho

Dwivedi, B. N.

Classification of ultraviolet stellar spectra using artificial neural networks

Gulati, R. K.; Gupta, Ranjan; Gothoskar, Pradeep +1 more

Scheme based on the artificial neural networks (ANNs) trained with multi-layer back propagation using single level network for classifying ultraviolet spectra in the IUE Low-Dispersion Spectra Reference Atlas is presented. We compare the classification results obtained from single-level network with the one from multi-level neural tree network. Bo…

Plasma diagnostics for SUMER on board the SOHO mission

Dwivedi, B. N.

IPS observations of the solar wind at 327 MHz - A comparison with ULYSSES observations

Janardhan, P.; Ananthakrishnan, S.; Balasubramanian, V. +1 more

X-ray studies of Be/X-ray binaries.

Saraswat, Priyamvada

In this thesis a study of some X-ray binaries in which a Be star is a primary has been undertaken in an effort to understand the nature of X-ray emission from these sources. The work attempts to answer questions regarding the structure of the circumstellar disk and its evolution with time. The thesis consists of two parts. The first part is devote…

The Be star phenomena. II - Spectral formation and structure of envelopes

Hirata, R.; Kogure, T.

The mechanisms of formation of the continuum and line spectra of Be stars and the morphology of their cool and hot envelopes are discussed in a review of recent theoretical and observational studies, supplementing the statistical evaluation of Kogure and Hirata (1982). Topics examined include the rapid rotation of Be stars, envelope dynamics, radi…

CA II K emission in Canopus.

Bappu, M. K. V.; Mekkaden, M. V.; Rao, N. K.

The changes in the Ca II K line profile of the F0 supergiant Canopus have been studied from the high dispersion coude spectrograms obtained since 1975. The emission in the core of the line is variable in a timescale of few days. Similar activity seems to be occurring in Mg II h and k lines also. This is attributed to the variability in the appeara…

I.U.E. observation of the CO molecule towards PSI Per (B5 Ve) and its implication.

Krishna Swamy, K. S.; Tarafdar, S. P.