BINA

Abstract

Elements heavier than iron are primarily produced by two neutron capture processes, the slow neutron-capture process (s-process) and the rapid-neutron capture process (r-process). As low to intermediate stars reach the end stage of their lives, the physical conditions in them are suitable for the occurrence of the s-process, thus producing half of the heavy elements. The other half of the heavy elements are the results of the r-process occurring at more exotic physical conditions such as those existing at the merging events of neutron stars or black holes. Recently a third neutron-capture process which occurs at conditions intermediate between that of s- and r-processes, the so-called intermediate neutron-capture process is introduced to explain the double enrichments of s- and r- processes shown by a group of carbon-enhanced metal-poor (CEMP) stars. The origin of most of the elements is now well identified but the exact conditions at which they are produced as well as the contribution of different neutron capture processes to their origin are still uncertain. The goal of our projects is to investigate the contribution that different neutron capture processes to the production of heavier elements and to measure how this contributes to the chemical evolution of our Galaxy.

Collaborators

Name	Affiliation & Contact
Dr. Drisya Karinkuzhi (P.I.)	Department of Physics, University of Calicut (UOC) (Calicut, Kerala, India) dr Drisya
Muhammed Riyas	Department of Physics, University of Calicut (UOC) (Calicut, Kerala, India) Riyas
Prof. Sophie Van Eck (P.I.)	Institute of Astronomy and Astrophysics, Université Libre de Bruxelles (ULB) (Brussels, Belgium) Prof SVA

Publications

"From the s-process to the i-process: A new perspective on the chemical enrichment of extrinsic stars"
Sophie Van Eck, Riano Giribaldi, Thibault Merle, Adrian Lambotte, Drisya Karinkuzhi, Stéphane Goriely, Arthur Choplin, Nicholas Storm, Lionel Siess, Maria Bergemann and Alain Jorissen, Accepted for publication as a Review in the MDPI Journal Galaxies in 2024

"Does the i-process occur at nearly solar metallicity ?"
Drisya Karinkuzhi, Sophie Van Eck, Alain Jorissen, Ana Escorza, Shreeya Shetye, Thibault Merle, Lionel Siess, Stephane Goriely, Hans Van Winckell, A&A, 2023, 677, 47

"A neutron star candidate in the long-period binary 56 Uma"
Ana Escorza, Drisya Karinkuzhi, Alain Jorissen, Sophie Van Eck, Joan T. Schmelz, Gerrit L Verschuur, Henri M. J. Boffin, Robert J. De Rosa, Hans Van Winkel, A&A Letters, 2023, 670, 14

"Sr and Ba abundances: Comparing machine-learning with star-by-star analyses. High-resolution re-analysis of suspected LAMOST barium stars"
Drisya Karinkuzhi, Sophie Van Eck, Alain Jorissen, Ana Escorza, Shreeya Shetye, Tibault Merle, Lionel Siess, Stephane Goriely, Hans Van Winckel, A&A, 2021, 654, 140

"Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars"
Drisya Karinkuzhi, Sophie Van Eck, Stephane Goriely, Lionel Siess, Alain Jorissen, Thibault Merle, Ana Escorza, Thomas Masseron, A&A, 2021, 645, 61

"Carbon-Enhanced Metal-Poor (CEMP)- stars enriched in s- and r- elements"
Drisya Karinkuzhi, Sophie Van Eck, Alain Jorissen, Stephane Goriely, Lionel Siess, Thibault Merle, Thomas Masseron , JApA, 2020, 41, 46

"Barium & related stars and their white dwarf companions II. Main sequence and sub-giant stars"
Ana Escorza Santos, Drisya Karinkuzhi, Alain Jorissen, Hans Van Winkle, Lionel Siess, P. North, B. Miszalski, H. M. J. Boffin, Shreeya Shetye, G-M. Oomen, Rajeev Manick, A&A, 2019, 626, 128, 23 pages

"Barium & related stars and their white dwarf companions I. Giants"
Alain Jorissen, H M J Boffin, Drisya Karinkuzhi, Sophie Van Eck, Ana Escorza Santos, Hans Van Winkel, A&A, 2019, 626,127, 28

"S stars and s-process in the Gaia era: Stellar parameters and chemical abundances of a sub-sample of S stars with new MARCS model atmospheres pages"
Shreeya Shetye, Sophie Van Eck, Hans Van Winkel, Alain Jorissen, Lionel Siess, Stephane Goriely, Ana Escorza Santos, Drisya Karinkuzhi, Bertrand Plez, A&A, 2018, 620,148, 21

"When binaries keep track of recent nucleosynthesis: Zr-Nb pair in extrinsic stars as an s-process diagnostic"
Drisya Karinkuzhi, Sophie Van Eck, Alain Jorissen, Stephane Goriely, Lionel Siess, Thibault Merle, Ana Escorza Santos, Mathieu Van der Swaelemen, H M J Boffin, Thomas Masseron, Shreeya Shetye, Bertrand Plez, A&A, 2018, 618, 32, 25

"Hertzsprung-Russell diagram and mass distribution of barium stars"
Ana Escorza, H M J Boffin, Alain Jorissen, Sophie Van Eck, Lionel Siess, Hans Van Winckel, Drisya Karinkuzhi, Shreeya Shetye, Dimitri Pourbaix, A&A, 2017, 608, 100, 13

Presentations

Contributed talk during the meeting ”Stellar Astrophysics in the era of GAIA, spectroscopic and Asteroseismic surveys ”, Munich, Germany August 2023

Contributed talk during the meeting Astrophysical Origins of Carbon, at the National Astronomical Observatory of Japan, Mitaka Campus, Tokyo From 2 to 5 September, 2024

Invited talk during 43rd Annual meeting of Astronomical Society of India at NIT, Rourkela, 15-19 February 2025

Proposals for telescope-time

• Characterising the i-process from UV lines of key diagnostic elements – 113.26NB.001 UVES – 5.5 hrs
  
• Key nucleosynthesis diagnostics in CEMP-rs stars: Nb/Zr thermometer, technetium and lead – UVES – 17 hrs 105.20LJ.001, 105.20LJ.002