Lalitha Sairam

I am an INSPIRE Faculty at the Indian Institute of Astrophysics. Formerly, I was a Post-doctoral fellow at the Tata Institute of Fundamental Research.

Research Interest

I am interested in understanding how a star can decide the fate of an orbiting planet around it. I am interested in understanding how frequently and powerful are stellar flares, how the occurrence of such flares can influence the exoplanets and investigate and characterise flare properties. Most of my work is based on multi-wavelengths monitoring campaigns using both space-based telescopes (Chandra, XMM-Newton, Swift, Suzaku, Astrosat) and ground-based telescopes (HCT, VBT and VLT).

Research Interests and CV

Stellar activity:

Cool stars in X-rays
Energy propagation through different layers of the stellar atmosphere
Coronal activity cycles

High-energy irradiation:

Stellar activity and their influence on the exoplanet
Star-planet interaction

Click here for my full CV.

Publications

Lalitha, S., Singh, K. P., Drake, S. A. and Kashyap, V.,"X-Raying the Coronae of HD 155555 ", 2015, ApJ 811, id.A.44L;

Lalitha, S., Poppenhaeger, K., Singh, K. P., Czesla, S. and Schmitt, J. H. M. M.,"X-Ray Emission from the Super-Earth Host GJ 1214 ", 2014, ApJ 790, id.A.11L;

Lalitha, S. and Schmitt, J.H.M.M., "X-ray activity cycle on the active ultra-fast rotator AB Doradus A?. Implication of correlated coronal and photometric variability ", 2013, A&A 559, id.A.119L;

Lalitha, S. and Schmitt, J.H.M.M., "Outer atmospheres of low mass stars - flare characteristics ", 2013, ASP Conference series Vol. 472;

Srivastava, A. K., Lalitha, S., and Pandey, J. C.,"Evidence of Multiple Slow Acoustic Oscillations in the Stellar Flaring Loops of Proxima Centauri ", 2013, ApJ 778, id.28L;

Lalitha, S., Fuhrmeister B., Wolter U., Schmitt J.H.M.M., Engels D. and Wieringa M.H., "A multi-wavelength view of AB Doradus outer atmosphere -- Simultaneous X-ray and optical spectroscopy at high cadence ", 2013, A&A 560, id.69L;

Poppenhaeger, K.; Czesla, S., Schröter, S., Lalitha, S., Kashyap, V., and Schmitt, J.H.M.M., "The high-energy environment in the super-earth system CoRoT-7 ", 2012,A&A 541,id.A26;

Fuhrmeister, B., Lalitha, S., Poppenhaeger, K., Rudolf, N., Liefke, C., Reiners, A., Schmitt, J.H.M.M., Ness, J.-U., "Multi-wavelength observations of Proxima Centauri ", 2011, A&A 534, id.A133;

Collaborations

ASTROSAT

ASTROSAT is a multi-wavelength space observatory launched on the 28 September 2015. Onboard ASTROSAT are 5 astronomical payloads : Ultraviolet Imaging Telescopes (UVIT), Large Area Xenon Proportional Counters (LAXPC), Soft X-ray Telescope (SXT), Cadmium-Zinc-Telluride coded-mask imager (CZTI) and Scanning Sky Monitor (SSM). I am part of the science team for ASTROSAT, and I am involved in simulation and analysis of SXT data.

Planet-host characterisation

Understanding and characterising the X-ray emission of potential planet hosts at the lower end of the HR diagram. In collaboration with Prof. J.H.M.M. Schmitt, Hamburger Sternwarte, Hamburg.

Accuracy of stellar parameters in planet hosting stars and Spectroscopic follow-up of well studied planet-hosts using 2.3m Vainu-Bappu telescope in India. In collaboration with Dr. C. von Essen, Stellar Astrophysics Centre (SAC), Aarhus university.

KOINET

Study of exoplanetary systems via transit timing variations. KOINET--A multi-site photometric follow-up of Kepler targets using middle-class telescopes around the world. In collaboration with Dr. C. von Essen, Georg-August-Universit ̈at and Stellar Astrophysics Centre (SAC), Aarhus university.

Flare oscillation

Post-flare coronal loop oscillation studies using wavelet analysis in late-type stars. In collaboration with Dr. A. K. Srivastava, ARIES/BHU.

Others

I am the co-ordinator of the journal club organised at IIA. For details click the link