| 1. |
- Reifarth, R., et al.
(författare)
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Nuclear astrophysics with radioactive ions at FAIR
- 2016
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
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Konferensbidrag (refereegranskat)abstract
- The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
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| 2. |
- Heil, M., et al.
(författare)
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A new Time-of-flight detector for the R 3 B setup
- 2022
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 58:12
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Tidskriftsartikel (refereegranskat)abstract
- We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.
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| 3. |
- Subjak, Jan, et al.
(författare)
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TOI-503: The First Known Brown-dwarf Am-star Binary from the TESS Mission
- 2020
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 159:4
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of an intermediate-mass transiting brown dwarf (BD), TOI-503b, from the TESS mission. TOI-503b is the first BD discovered by TESS, and it has circular orbit around a metallic-line A-type star with a period of P.=.3.6772.+/-.0.0001 days. The light curve from TESS indicates that TOI-503b transits its host star in a grazing manner, which limits the precision with which we measure the BD's radius ( = R 1.34+ R b 0.150.26 J). We obtained highresolution spectroscopic observations with the FIES, Ondr.ejov, PARAS, Tautenburg, and TRES spectrographs, and measured the mass of TOI-503b to be Mb.=.53.7.+/-.1.2 MJ. The host star has a mass of Ma.=.1.80.+/-.0.06Me, a radius of Ra.=.1.70.+/-.0.05Re, an effective temperature of Teff.=.7650.+/-.160 K, and a relatively high metallicity of 0.61.+/-.0.07 dex. We used stellar isochrones to derive the age of the system to be 180 Myr, which places its age between that of RIK 72b (a 10 Myr old BD in the Upper Scorpius stellar association) and AD 3116b (a 600 Myr old BD in the Praesepe cluster). Given the difficulty in measuring the tidal interactions between BDs and their host stars, we cannot precisely say whether this BD formed in situ or has had its orbit circularized by its host star over the relatively short age of the system. Instead, we offer an examination of plausible values for the tidal quality factor for the star and BD. TOI-503b joins a growing number of known short-period, intermediate-mass BDs orbiting mainsequence stars, and is the second such BD known to transit an A star, after HATS-70b. With the growth in the population in this regime, the driest region in the BD desert (35-55MJ sin i) is reforesting.
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