| 1. |
- Dai, F., et al.
(författare)
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The Discovery and Mass Measurement of a New Ultra-short-period Planet: K2-131
- 2017
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 154:6, s. 226-
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of a new ultra-short-period planet and summarize the properties of all such planets for which the mass and radius have been measured. The new planet, EPIC 228732031b, was discovered in K2 Campaign 10. It has a radius of 1.81-0.12+0.16 R_Earth and orbits a G dwarf with a period of 8.9 hr. Radial velocities obtained with Magellan/PFS and TNG/HARPS-N show evidence for stellar activity along with orbital motion. We determined the planetary mass using two different methods: (1) the “floating chunk offset” method, based only on changes in velocity observed on the same night; and (2) a Gaussian process regression based on both the radial velocity and photometric time series. The results are consistent and lead to a mass measurement of 6.5+/- 1.6 M_Earth and a mean density of 6.0-2.7+3.0 g cm‑3.
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| 2. |
- Gorska, M, et al.
(författare)
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Cd-98(48)50 : The two-proton-hole spectrum in Sn-100(50)50
- 1997
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 79:13, s. 2415-2418
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Cd-98, two proton holes from Sn-100, were identified and studied for the first time, using in-beam spectroscopy with highly selective ancillary detectors. The structure of the (pi g(9/2))(-2) two-proton-hole spectrum below a T-1/2 = 0.48(16) mu s isomer is deduced and compared to shell-model predictions. A tentative I-pi = (8(+)) assignment, as suggested by systematics, yields a strongly reduced B(E2,8(+) --> 6(+)) = 0.44((+20)(-10)) W.u., corresponding to an effective proton charge of e(pi) = 0.85((+20)(-10))e, which is at variance with existing theoretical predictions.
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| 3. |
- Gorska, M, et al.
(författare)
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Spectroscopy of the T-z=1 nuclei close to Sn-100
- 1997
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 28:1-2, s. 303-307
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Tidskriftsartikel (refereegranskat)abstract
- The two nuclei Cd-98 and Sn-102, closest neighbours of Sn-100, have been studied with a recoil catcher setup, following the reactions: Ni-58(Ti-46, alpha 2n)Cd-98 and Ni-58(Cr-50, alpha 2n)Sn-102. Long lived isomeric states were measured in Cd-98 I-pi = (8+), t(1/2) = 0.48(8) mu s and in Sn-102 I-pi = (6(+)) with t(1/2) = 1.0(6) mu s. The proposed experimental level schemes of the isomeric decay are presented and compared to the shell model predictions.
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| 4. |
- Guenther, E. W., et al.
(författare)
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K2-106, a system containing a metal-rich planet and a planet of lower density
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 608, s. 93-
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Tidskriftsartikel (refereegranskat)abstract
- Planets in the mass range from 2 to 15 M_Earth are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss.We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days. Although the two planets have similar masses, their densities are very different. For K2-106b we derive Mb=8.36-0.94+0.96 M_Earh, Rb=1.52+/-0.16 R_Earth, and a high density of 13.1-3.6+5.4 g/cm^3. For K2-106c, we find Mc=5.8-3.0+3.3 M_Earth, Rc=2.50-0.26+0.27 R_Earth and a relatively low density of 2.0-1.1+1.6 g/cm^3.Since the system contains two planets of almost the same mass, but different distances from the host star, it is an excellent laboratory to study atmospheric escape. In agreement with the theory of atmospheric-loss processes, it is likely that the outer planet has a hydrogen-dominated atmosphere. The mass and radius of the inner planet is in agreement with theoretical models predicting an iron core containing 80+20-30% of its mass. Such a high metal content is surprising, particularly given that the star has an ordinary (solar) metal abundance. We discuss various possible formation scenarios for this unusual planet.
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| 5. |
- Kownacki, J, et al.
(författare)
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The isospin dependent p-n multiplets in the region of doubly magic Sn-100
- 1996
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Konferensbidrag (refereegranskat)abstract
- Experimental data on p-n multiplets appearing in the nuclei near double-magic Sn-100 accesible in heavy-ion fusion-evaporation experiments have been analyzed. Proton-rich nuclei in this region have been investigated using the NORDBALL array. A Ni-58 beams at energies of 270 Mev on Fe-54 and 261 MeV on Cr-50 targets were used. Reaction channel separation was achieved with a 4 pi charged particle multi-detector set-up together with a 1 pi neutron detector wall placed in the forward direction. On the basis of gamma gamma-coincidence and angular correlation relations a level schemes of several light Sn, In, Sb, Te and I nuclei were observed for the first time in the present experiment. The observed structure of nuclei are discussed in the framework of the nuclear shell-model. The p-n multiplets in the A similar to 100 region corresponding to the nucleon pairs with mixed configurations has been considered as a playground for the tests of the T = 0 and T = 1 parts of the effective interaction.
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| 6. |
- Kownacki, J, et al.
(författare)
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The isospin dependent p-n multiplets in the region of doubly magic Sn-100
- 1996
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Ingår i: ACTA PHYSICA POLONICA B. - : POLISH ACAD SCIENCES INST PHYSICS. ; 27:1-2, s. 87-97
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Experimental data on p-n multiplets appearing in the nuclei near double-magic Sn-100 accesible in heavy-ion fusion-evaporation experiments have been analyzed. Proton-rich nuclei in this region have been investigated using the NORDBALL array. A Ni-58 beams
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| 7. |
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| 8. |
- Lipoglavšek, M., et al.
(författare)
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In-beam study of 102Sn
- 1996
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Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 356:3, s. 239-240
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in 102Sn have been identified for the first time, in an in-beam γ-ray spectroscopic experiment. Two γ-ray transitions with energies 1472 and 497 keV following the decay of the seniority 6+ isomer with t1/2 = 1.0(5) μs were unambiguously assigned to 102Sn. Due to the very low cross section of about 2 μb for producing 102Sn in the reaction 50Cr(58Ni,1α2n), a highly selective detector setup utilizing NORDBALL ancillary detectors and a recoil catcher device was used. High γ-ray detection efficiency was achieved with two EUROBALL Ge cluster detectors.
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| 9. |
- Cederkall, J, et al.
(författare)
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First evidence for excited states in In-101
- 1996
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Ingår i: PHYSICAL REVIEW C-NUCLEAR PHYSICS. - : AMER INST PHYSICS. - 0556-2813. ; 53:4, s. 1955-1958
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The first evidence for excited states in In-101 is presented. In-101 is the lightest In isotope observed in an in-beam experiment. Two gamma-ray transitions at 1309 and 341 keV, respectively, are strong candidates for a cascade to the ground state in this
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| 10. |
- Cederkall, J, et al.
(författare)
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Maximum spin aligned states in Ag-98(47)51
- 1998
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Ingår i: EUROPEAN PHYSICAL JOURNAL A. - : SPRINGER VERLAG. - 1434-6001. ; 1:1, s. 7-9
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- New excited states have been observed in the neutron deficient isotope Ag-98 following the Ni-58+Cr-50-->Te-108* heavy-ion reaction. One of these states may be interpreted as a maximum spin aligned state of the pi g(9/2)(-3) nu vg(7/2) configuration. Othe
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