1.3m Robotic Telescope at Devasthal
Projects >> 1.3m Robotic Telescope
Scientific Objectives
The prime objective of the proposed 130 cm automated telescope is photometric monitoring of variable objects and transient sources in the sky. The telescope should also be capable of carring out long exposure photometric observations of galactic and extragalactic objects. A number of scientific programs are planned to carry out using the 130 cm telescope some of which are described below.
Variable stars and Asteroseismology
Study of intrinsic variability in stellar luminosity has played a major role in understanding the invisible interior of the stars, their chemical composition and the magnetic field strength. The variation is caused due to pulsations on the surface of the interiors of the stars. Like the seismic waves on Earth, some of the pulsating modes can go deeper into the stars. Therefore, by analyzing various frequency modes of the pulsations it is possible to infer the internal constitution of stars.
Survey for pulsations in chemically peculiar stars
Chemically peculiar stars are the hydrogen burning main sequence stars in the spectral range B8-F0. These stars have anomalous abundances; an over-abundance of heavy elements up to a factor of 105 and an under-abundance of some light elements up to a factor of 10-2. Among these a group of stars known as A-peculiar (Ap) stars have strong magnetic fields. Some of the Ap stars have been found to be rapidly oscillating. These are called roAp stars. The stars are located in the classical instability strip of the HR diagram. The roAp stars pulsate in the high-overtone, non-radial p-mode with low oscillation amplitudes and periods ranging from 5 to 15 minutes. Some of these modes are similar to those observed in the Sun. However, contrary to the Sun, roAp stars have strong magnetic field. It is widely believed that chemical peculiarity combined with the magnetic field may be responsible for the oscillations. This conjecture still needs to be formally proved. The photometric variability of these stars can give us great insight into the possible mechanisms that are in work in these objects.
Pulsating white dwarfs
White dwarfs variables exhibit non-radial g-mode pulsations with periods in the range 100-1000s. periods in the range The g-mode pulsations can probe up to the inner 99% of the stellar interior. One expects to learn more about the stellar interior from white dwarf variables than from any other class of pulsating stars because white dwarfs are not as centrally condensed. As a result of which the pulsations amplitude within their model interiors does not diminish as rapidly as in other types of pulsators. Also, their high density and temperatures make them ideal cosmic laboratories to understand fundamental physics under extreme conditions. It is expected that 98-99% of stars end up in the white dwarf stage.
