scholarly journals The Fe/O elemental abundance ratio in the solar wind as observed with SOHO CELIAS CTOF

1999 ◽  
Vol 104 (A11) ◽  
pp. 24769-24780 ◽  
Author(s):  
M. R. Aellig ◽  
S. Hefti ◽  
H. Grünwaldt ◽  
P. Bochsler ◽  
P. Wurz ◽  
...  
Keyword(s):  
Solar Wind ◽  
Abundance Ratio ◽  
Elemental Abundance

scholarly journals Signature and escape of highly fractionated plasma in an active region

2021 ◽  
Vol 508 (2) ◽  
pp. 1831-1841
Author(s):  
David H Brooks ◽  
Stephanie L Yardley
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Active Region ◽  
Active Regions ◽  
Abundance Ratio ◽  
Elemental Abundance ◽  
Composition Analysis ◽  
Closed Field ◽  
Coronal Loops ◽  
Magnetic Field Model

ABSTRACT Accurate forecasting of space weather requires knowledge of the source regions where solar energetic particles (SEP) and eruptive events originate. Recent work has linked several major SEP events in 2014, January, to specific features in the host active region (AR 11944). In particular, plasma composition measurements in and around the footpoints of hot, coronal loops in the core of the active region were able to explain the values later measured in situ by the Wind spacecraft. Due to important differences in elemental composition between SEPs and the solar wind, the magnitude of the Si/S elemental abundance ratio emerged as a key diagnostic of SEP seed population and solar wind source locations. We seek to understand if the results are typical of other active regions, even if they are not solar wind sources or SEP productive. In this paper, we use a novel composition analysis technique, together with an evolutionary magnetic field model, in a new approach to investigate a typical solar active region (AR 11150), and identify the locations of highly fractionated (high Si/S abundance ratio) plasma. Material confined near the footpoints of coronal loops, as in AR 11944, that in this case have expanded to the AR periphery, show the signature, and can be released from magnetic field opened by reconnection at the AR boundary. Since the fundamental characteristics of closed field loops being opened at the AR boundary is typical of active regions, this process is likely to be general.

The Fe/O elemental abundance ratio in the solar wind

1999 ◽  
Author(s):  
M. R. Aellig ◽  
H. Holweger ◽  
P. Bochsler ◽  
P. Wurz ◽  
H. Grünwaldt ◽  
...  
Keyword(s):  
Solar Wind ◽  
Abundance Ratio ◽  
Elemental Abundance

scholarly journals Depletion of 15N in the center of L1544: Early transition from atomic to molecular nitrogen?

2018 ◽  
Vol 615 ◽  
pp. L16 ◽  
Author(s):  
K. Furuya ◽  
Y. Watanabe ◽  
T. Sakai ◽  
Y. Aikawa ◽  
S. Yamamoto
Keyword(s):  
Gas Phase ◽  
Molecular Nitrogen ◽  
Abundance Ratio ◽  
Elemental Abundance ◽  
Evolutionary Stage ◽  
Gas Phase Chemistry ◽  
Far Ultraviolet ◽  
Phase Chemistry ◽  
Grain Surface

We performed sensitive observations of the N15ND+(1–0) and 15NND+(1–0) lines toward the prestellar core L1544 using the IRAM 30 m telescope. The lines are not detected down to 3σ levels in 0.2 km s−1 channels of ~6 mK. The non-detection provides the lower limit of the 14N/15N ratio for N2D+ of ~700–800, which is much higher than the elemental abundance ratio in the local interstellar medium of ~200–300. The result indicates that N2 is depleted in 15N in the central part of L1544, because N2D+ preferentially traces the cold dense gas, and because it is a daughter molecule of N2. In situ chemistry is probably not responsible for the 15N depletion in N2; neither low-temperature gas phase chemistry nor isotope selective photodissociation of N2 explains the 15N depletion; the former prefers transferring 15N to N2, while the latter requires the penetration of interstellar far-ultraviolet (FUV) photons into the core center. The most likely explanation is that 15N is preferentially partitioned into ices compared to 14N via the combination of isotope selective photodissociation of N2 and grain surface chemistry in the parent cloud of L1544 or in the outer regions of L1544, which are not fully shielded from the interstellar FUV radiation. The mechanism is most efficient at the chemical transition from atomic to molecular nitrogen. In other words, our result suggests that the gas in the central part of L1544 has previously gone trough the transition from atomic to molecular nitrogen in the earlier evolutionary stage, and that N2 is currently the primary form of gas-phase nitrogen.

Determination of the 36 Ar/ 38 Ar isotopic abundance ratio of the solar wind using SOHO/CELIAS/MTOF

2001 ◽  
Vol 65 (24) ◽  
pp. 4589-4596 ◽  
Author(s):  
James M. Weygand ◽  
Fred M. Ipavich ◽  
Peter Wurz ◽  
John A. Paquette ◽  
Peter Bochsler
Keyword(s):  
Solar Wind ◽  
Abundance Ratio ◽  
Isotopic Abundance

What CO 2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

2008 ◽  
Vol 366 (1883) ◽  
pp. 4183-4203 ◽  
Author(s):  
Chris J Ballentine ◽  
Greg Holland
Keyword(s):  
Solar Wind ◽  
Isotopic Composition ◽  
Solar Nebula ◽  
Noble Gases ◽  
Noble Gas ◽  
Isotopic Fractionation ◽  
Elemental Abundance ◽  
Published Data ◽  
Abundance Pattern ◽  
New Information

Study of commercially produced volcanic CO 2 gas associated with the Colorado Plateau, USA, has revealed substantial new information about the noble gas isotopic composition and elemental abundance pattern of the mantle. Combined with published data from mid-ocean ridge basalts, it is now clear that the convecting mantle has a maximum 20 Ne/ 22 Ne isotopic composition, indistinguishable from that attributed to solar wind-implanted (SWI) neon in meteorites. This is distinct from the higher 20 Ne/ 22 Ne isotopic value expected for solar nebula gases. The non-radiogenic xenon isotopic composition of the well gases shows that 20 per cent of the mantle Xe is ‘solar-like’ in origin, but cannot resolve the small isotopic difference between the trapped meteorite ‘Q’-component and solar Xe. The mantle primordial 20 Ne/ 132 Xe is approximately 1400 and is comparable with the upper end of that observed in meteorites. Previous work using the terrestrial 129 I– 129 Xe mass balance demands that almost 99 per cent of the Xe (and therefore other noble gases) has been lost from the accreting solids and that Pu–I closure age models have shown this to have occurred in the first ca 100 Ma of the Earth's history. The highest concentrations of Q-Xe and solar wind-implanted (SWI)-Ne measured in meteorites allow for this loss and these high-abundance samples have a Ne/Xe ratio range compatible with the ‘recycled-air-corrected’ terrestrial mantle. These observations do not support models in which the terrestrial mantle acquired its volatiles from the primary capture of solar nebula gases and, in turn, strongly suggest that the primary terrestrial atmosphere, before isotopic fractionation, is most probably derived from degassed trapped volatiles in accreting material. By contrast, the non-radiogenic argon, krypton and 80 per cent of the xenon in the convecting mantle have the same isotopic composition and elemental abundance pattern as that found in seawater with a small sedimentary Kr and Xe admix. These mantle heavy noble gases are dominated by recycling of air dissolved in seawater back into the mantle. Numerical simulations suggest that plumes sampling the core–mantle boundary would be enriched in seawater-derived noble gases compared with the convecting mantle, and therefore have substantially lower 40 Ar/ 36 Ar. This is compatible with observation. The subduction process is not a complete barrier to volatile return to the mantle.

scholarly journals Measuring elemental abundance ratios in protoplanetary disks at millimeter wavelengths

2020 ◽  
Vol 638 ◽  
pp. A110 ◽  
Author(s):  
D. Fedele ◽  
C. Favre
Keyword(s):  
Protoplanetary Disks ◽  
Abundance Ratio ◽  
Elemental Abundance ◽  
Physical Parameters ◽  
Minor Effect ◽  
Line Flux ◽  
Nearby Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
A Minor

Over million years of evolution, gas dust and ice in protoplanetary disks can be chemically reprocessed. There is evidence that the gas-phase carbon and oxygen abundances are subsolar in disks belonging to nearby star forming regions. These findings have a major impact on the composition of the primary atmosphere of giant planets (but it may also be valid for super-Earths and sub-Neptunes) as they accrete their gaseous envelopes from the surrounding material in the disk. In this study, we performed a thermochemical modeling analysis with the aim of testing how reliable and robust are the estimates of elemental abundance ratios based on (sub)millimeter observations of molecular lines. We created a grid of disk models for the following different elemental abundance ratios: C/O, N/O, and S/O, and we computed the line flux of a set of carbon-nitrogen and sulphur-bearing species, namely CN, HCN, NO, C2H, c–C3H2, H2CO, HC3N, CH3CN, CS, SO, H2S, and H2CS, which have been detected with present (sub)millimeter facilities such as ALMA and NOEMA. We find that the line fluxes, once normalized to the flux of the 13CO J = 2−1 line, are sensitive to the elemental abundance ratios. On the other hand, the stellar and disk physical parameters have only a minor effect on the line flux ratios. Our results demonstrate that a simultaneous analysis of multiple molecular transitions is a valid approach to constrain the elemental abundance ratio in protoplanetary disks.

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