Cerium features in kilonova near-infrared spectra: implication from a chemically peculiar star
arXiv:2306.04697 · doi:10.3847/1538-4357/acdc95
Abstract
Observations of the kilonova from a neutron star merger event GW170817 opened a way to directly study r-process nucleosynthesis by neutron star mergers. It is, however, challenging to identify the individual elements in the kilonova spectra due to lack of complete atomic data, in particular, at near-infrared wavelengths. In this paper, we demonstrate that spectra of chemically peculiar stars with enhanced heavy element abundances can provide us with an excellent astrophysical laboratory for kilonova spectra. We show that the photosphere of a late B-type chemically peculiar star HR 465 has similar lanthanide abundances and ionization degrees with those in the line forming region in a kilonova at days after the merger. The near-infrared spectrum of HR 465 taken with Subaru/IRD indicates that Ce III lines give the strongest absorption features around 16,000 A and there are no other comparably strong transitions around these lines. The Ce III lines nicely match with the broad absorption features at 14,500 A observed in GW170817 with a blueshift of v=0.1c, which supports recent identification of this feature as Ce III by Domoto et al. (2022).
arXiv comment12 pages, 6 figures, accepted for publication in ApJ
References in corpus (29)
- Astropy: A Community Python Package for Astronomy
- The chemical composition of the Sun
- The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
- Multi-messenger Observations of a Binary Neutron Star Merger
- Transient Events from Neutron Star Mergers
- Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
- Electromagnetic Counterparts of Compact Object Mergers Powered by the Radioactive Decay of R-process Nuclei
- Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
- A kilonova as the electromagnetic counterpart to a gravitational-wave source
- The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
- Opacities and Spectra of the r-process Ejecta from Neutron Star Mergers
- The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South
- Identification of strontium in the merger of two neutron stars
- Radiative Transfer Simulations for Neutron Star Merger Ejecta
- Kilonova from post-merger ejecta as an optical and near-infrared counterpart of GW170817
- AT2017gfo: an anisotropic and three-component kilonova counterpart of GW170817
- Systematic Opacity Calculations for Kilonovae
- Neutron-capture elements in the very metal-poor star HD122563
- The first direct double neutron star merger detection: implications for cosmic nucleosynthesis
- Radiative transfer simulation for the optical and near-infrared electromagnetic counterparts to GW170817
- A line-binned treatment of opacities for the spectra and light curves from neutron star mergers
- Modelling the spectra of the kilonova AT2017gfo -- I: The photospheric epochs
- Signatures of r-process elements in kilonova spectra
- New catalogue of Chemically Peculiar stars, and Statistical Analysis
- Production of very light elements and strontium in the early ejecta of neutron star mergers
- Physical conditions for the r-process I. radioactive energy sources of kilonovae
- Spherical symmetry in the kilonova AT2017gfo/GW170817
- NLTE Effects on Kilonova Expansion Opacities
- Nebular Emission from Lanthanide-rich Ejecta of Neutron Star Merger