R. Rajamohan
Articles written in Journal of Astrophysics and Astronomy
Volume 1 Issue 2 December 1980 pp 155-164
Supernovae and the Ap phenomenon
We put forward evidence that relates the phenomenon of the chemically peculiar stars of the upper main sequence to Supernovae explosions in young clusters. In the Upper Scorpius region we find that a supernova shell has interacted with dense clouds and that the peculiar stars lie close to or along the edges of interaction.
We argue that the stars at or near the cloud faces are capable of acquiring this enriched material which is sufficiently slowed down. The magnetic accretion process of Havnes and Conti provides the mechanism of acquisition. This process with the associated magnetic braking accounts for the build-up in abundance anomalies and the slowing down of rotation with age.
Volume 3 Issue 3 September 1982 pp 267-276
HD 147010: The Ap star in the reflection nebula vdB 102 in upper Scorpius region
HD 147010, which is in the reflection nebula vd B 102, has been found to be a hot Ap silicon star rather than a normal A supergiant. From the
Volume 9 Issue 2 June 1988 pp 107-116
Effects of rotation on the colours and line indices of stars 1. The alpha Persei cluster
Analysis of the available observational data for the α-Persei cluster members shows that rotation effects on the intermediate-band indices c1 and (
The binaries and peculiar stars are found to behave differently in the colour excess (due to rotation) versus
Volume 11 Issue 2 June 1990 pp 167-191
Effects of rotation on the colours and line indices of stars - 2. The effect on
The intrinsic
Volume 13 Issue 1 March 1992 pp 61-107
Effects of rotation on the colours and line indices of stars 5. The ZRMS and the ZRZAMS
The observed
The observed slopes of the rotation effects were used to determine the zero rotation main sequence values of the intermediate band photometric indices for selected clusters. We also corrected the observed indices for each star in each cluster using the theoretical predictions of Collins and Sonneborn and derived the ZRMS values for each cluster. The agreement between the two determinations is found to be good. The various ZRMS curves were utilised to derive the ZRZAMS values. A preliminary calibration of the absolute visual magnitudes as a function of α valid for ZRZAMS has also been derived. The ZRMS values of the intermediate band photometric indices for different clusters and the ZRZAMS values are listed as a function of α.
Volume 13 Issue 1 March 1992 pp 109-128
Jacqueline D’Souza Annamma Mathew R. Rajamohan
The effect of rotation on the observed colours of stars has been considered as a possible cause for the blue straggler phenomenon in clusters listed by Mermilliod (1982). It appears that this phenomenon is definitely not real in the case of the late B and early A spectral type blue stragglers that are intrinsic slow rotators. Among clusters containing the early B type blue stragglers it is found that the anomalous position of the stragglers in NGC 6633, NGC 6475 and NGC 2516 cannot be accounted for by rotation effects alone.
Volume 43, 2022
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