Abstract
The origin and evolution of hydrogen-deficient stars are not yet adequately understood. Their chemical peculiarities, along with hydrogen-deficiency, makes them stand out from the rest and sheds light on their possible origin. Severe fluorine enrichment (of the order of 800–8000) is one such characteristic feature of a class of hydrogen deficient stars, mainly the RCBs (R Coronae Borealis stars) and cool EHes (Extreme Helium stars) which enforces their close connection. For hot EHes, this relationship with the cooler EHes, based on their fluorine abundance is unexplored. Here, first estimates of fluorine abundances in hot EHes are presented and discussed in the light of their cooler counterparts to try to establish an evolutionary connection. The relation between these fluorine estimates with the other elemental abundances observed in these stars plays a pivotal role to predict the formation and evolution of these exotic stars.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bhowmick A., Pandey G., Lambert D. L. 2020, ApJ, 891, 40
Clayton G. C., Geballe T. R., Herwig F., Fryer C., Asplund M. 2007, ApJ, 662, 1220
Guerço R., Cunha K., Smith V. V. et al. 2019, ApJ, 876, 43
Hema B. P., Pandey G., Kamath D. et al. 2017, PASP, 129, 104202
Hubeny, I., Lanz, T., Jeffery, C. 1994, Newsletter on Analysis of Astronomical Spectra (TLUSTY and SYNSPEC: a User’s Guide), Vol. 20, St. Andrews Univ., St. Andrews
Iben, I., Jr., Tutukov, A. V. 1984, ApJS, 54, 335
Iben, I., Jr., Kaler, J. B., Truran, J. W., Renzini, A. 1983, ApJ, 264, 605
Jeffery, C. S. 2017, MNRAS, 470, 3557
Jeffery, C. S., Heber, U., Hill, P. W., et al. 1996, in Jeffery C. S., Heber U., eds, ASP Conf. Ser. 96, Hydrogen Deficient Stars, ASP, San Francisco, CA, p. 471
Jönsson, H., Ryde, N., Harper, G. M., et al. 2014, ApJL, 789, L41
Jönsson, H., Ryde, N., Spitoni, E., et al. 2017, ApJ, 835, 50
Lauer, A., Chatzopoulos, E., Clayton, G. C., Frank, J., Marcello, D. C. 2019, MNRAS, 488, 438
Maiorca, E., Uitenbroek, H., Uttenthaler, S., et al. 2014, ApJ, 788, 149
Menon, A., Herwig, F., Denissenkov, P. A., et al. 2013, ApJ, 772, 59
Menon, A., Karakas, A. I., Lugaro, M., Doherty, C. L., Ritter, C. 2019, MNRAS, 482, 2320
Moore, C. E., 1972, A multiplet table of astrophysical interest - Pt.1: Table of multiplets - Pt.2: Finding list of all lines in the table of multiplets, SAO/NASA Astrophysics Data System, https://ui.adsabs.harvard.edu/abs/1972mtai.book.....M
Pandey, G. 2006, ApJL, 648, L143
Pandey, G., Lambert, D. L. 2011, ApJ, 727, 122
Pandey, G., Lambert, D. L. 2017, ApJ, 847, 127
Pandey, G., Lambert, D. L., Jeffery, C. S., Rao, N. K. 2006, ApJ, 638, 454
Pandey, G., Lambert, D. L., Kameswara Rao, N. 2008, ApJ, 674, 1068
Pandey, G., Kameswara Rao, N., Jeffery, C. S., Lambert, D. L. 2014, ApJ, 793, 76
Webbink, R. F. 1984, ApJ, 277, 355
Wiese, W. L., Fuhr, J. R., Deters, T. M. 1996, Atomic Transition Probabilities of Carbon, Nitrogen, and Oxygen: A Critical Data Compilation, National Institute of Standards and Technology, Washington, D.C.
Zhang, X., Jeffery, C. S. 2012, MNRAS, 426, L81
Acknowledgements
The authors thank the organizing committee of the ‘150 Years of Periodic Table’ conference, and IIA, Bengaluru for all their support.
Author information
Authors and Affiliations
Corresponding author
Additional information
This article is part of the Topical Collection: Chemical Elements in the Universe: Origin and Evolution.
Rights and permissions
About this article
Cite this article
Bhowmick, A., Pandey, G. & Lambert, D.L. Fluorine detection in hot extreme helium stars. J Astrophys Astron 41, 40 (2020). https://doi.org/10.1007/s12036-020-09659-2
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s12036-020-09659-2