Toward an Astrophysical Theory of Chondrites

Shu, Frank H.; Shang, Hsien; Lee, Typhoon

doi:10.1126/science.271.5255.1545

Cited by 499 publications

(437 citation statements)

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“…The heating rate applied to our ice analogs is on the same order of magnitude than the one dust grains experience during the periodic radial excursions considered in the fluctuating X-wind model for CAIs and chondrules formation (Shu et al 1996(Shu et al , 1997(Shu et al , 2001. A similar behavior is expected for ice mantles at a given distance from the central object, as they are heated with an approximate heating rate of 1 K/century.…”

Section: Discussionmentioning

confidence: 72%

“…-Circumstellar ices are heated during the star formation, as the temperature of the central object increases. Some grains undergo transient episodes of "flash-heating" lasting up to hundreds of hours according to the fluctuating X-wind model for CAIs and chondrules formation (Shu et al 1996(Shu et al , 1997(Shu et al , 2001). -Cometary ices are heated during late thermal evolution of comets around already formed stars, as the comet comes closer to the star during its orbit.…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

“…On the one hand, grains at a certain distance are heated (approximately 1 K/century; Viti & Williams 1999) as the temperature of the protostar increases. On the other hand, grains are also able to undergo periodic radial excursions to distances less than 0.1 AU from the central protostar on short timescales (from a few to hundreds of hours), according to the fluctuating X-wind model for the formation of Ca-Al-rich inclusions (CAIs) and chondrules (Shu et al 1996(Shu et al , 1997(Shu et al , 2001). …”

Section: Introductionmentioning

confidence: 99%

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Thermal desorption of circumstellar and cometary ice analogs

Martín-Doménech

Muñoz

Bueno

et al. 2014

A&A

108

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Context. Thermal annealing of interstellar ices takes place in several stages of star formation. Knowledge of this process comes from a combination of astronomical observations and laboratory simulations under astrophysically relevant conditions. Aims. For the first time we present the results of temperature programmed desorption (TPD) experiments with pre-cometary ice analogs composed of up to five molecular components: H 2 O, CO, CO 2 , CH 3 OH, and NH 3 . Methods. The experiments were performed with an ultra-high vacuum chamber. A gas line with a novel design allows the controlled preparation of mixtures with up to five molecular components. Volatiles desorbing to the gas phase were monitored using a quadrupole mass spectrometer, while changes in the ice structure and composition were studied by means of infrared spectroscopy. Results. The TPD curves of water ice containing CO, CO 2 , CH 3 OH, and NH 3 present desorption peaks at temperatures near those observed in pure ice experiments, volcano desorption peaks after water ice crystallization, and co-desorption peaks with water. Desorption peaks of CH 3 OH and NH 3 at temperatures similar to the pure ices takes place when their abundance relative to water is above ∼3% in the ice matrix. We found that CO, CO 2 , and NH 3 also present co-desorption peaks with CH 3 OH, which cannot be reproduced in experiments with binary water-rich ice mixtures. These are extensively used in the study of thermal desorption of interstellar ices. Conclusions. These results reproduce the heating of circumstellar ices in hot cores and can be also applied to the late thermal evolution of comets. In particular, TPD curves represent a benchmark for the analysis of the measurements that mass spectrometers on board the ESA-Rosetta cometary mission will perform on the coma of comet 67P/Churyumov-Gerasimenko, which will be active before the arrival of Rosetta according to our predictions.

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Section: Discussionmentioning

confidence: 72%

Section: Astrophysical Implicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal desorption of circumstellar and cometary ice analogs

Martín-Doménech

Muñoz

Bueno

et al. 2014

A&A

108

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“…However, there are more developed views of the thermal structure of the solar nebula (see [163]). The X-wind scenario of Shu, Shang, & Lee [164] would certainly provide a hot processing zone. It was proposed by Wood [165] that shock heating could play a major role in both CAI and chondrule formation.…”

Section: Meteoritic Observations On Short-lived Nucleimentioning

confidence: 99%

Short-lived nuclei in the early Solar System: Possible AGB sources

et al. 2006

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The abundances of short-lived radionuclides in the early solar system (ESS) are reviewed, as well as the methodology used in determining them. These results are compared with the inventory estimated for a uniform galactic production model. It is shown that, to within a factor of two, the observed abundances of 238 U, 235 U, 232 Th, 244 Pu, 182 Hf, 146 Sm, and 53 Mn are roughly compatible with long-term galactic nucleosynthesis. 129 I is an exception, with an ESS inventory much lower than expected from uniform production. The isotopes 107 Pd, 60 Fe, 41 Ca, 36 Cl, 26 Al, and 10 Be require late addition to the protosolar nebula. 10 Be is the product of energetic particle irradiation of the solar system as most probably is 36 Cl. Both of these nuclei appear to be present when 26 Al is absent. A late injection by a supernova (SN) cannot be responsible for most of the short-lived nuclei without excessively producing 53 Mn; it can however be the source of 53 Mn itself and possibly of 60 Fe. If a late SN injection is responsible for these two nuclei, then there remains the problem of the origin of 107 Pd and several other isotopes. Emphasis is given to an AGB star as a source of many of the nuclei, including 60 Fe; this possibility is explored with a new generation of stellar models. It is shown that if the dilution factor (i.e. the ratio of the contaminating mass to the solar parental cloud mass) is f 0 ∼ 4×10 −3 , a reasonable representation for many nuclei is obtained; this requires that ( 60 Fe/ 56 Fe) ESS ∼ 10 −7 to 2×10 −6 . The nuclei produced by an AGB source do not include 53 Mn, 10 Be or 36 Cl if it is very abundant. The role of irradiation is discussed with regard to 26 Al, 36 Cl and 41 Ca, and the estimates of bulk solar abundances of these isotopes are commented on. The conflict between various scenarios is emphasized as well as the current absence of an astrophysically plausible global interpretation for all the existing data. Examination of abundances for the actinides indicates that a quiescent interval of ∼ 10 8 years is required for actinide group production. This is needed in order to explain the data on 244 Pu and the new bounds on 247 Cm. Because this quiescent interval is not compatible with the 182 Hf data, a separate type of r-process event is needed for at least the actinides, distinct from the two types that have previously been identified. The apparent coincidence of the 129 I and trans-actinide time scales suggests that the last heavy r contribution was from an r-process that produced very heavy nuclei but without fission recycling so that the yields at Ba and below (including I) were governed by fission.

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“…Consequently, it is hard to associate the 3 day period of the closest in extrasolar planets with a special stellar rotation rate or with . R x In the X-wind model of chondrule formation, a geometrically thin, optically thick disk of planetesimals interior to suffers R x mutual collisions and heating from magnetic flares (Shu, Shang, & Lee 1996;Shu et al 2001). Materials from these planetesimals become protochondrules.…”

Section: Magnetic Disk Truncation and The X-wind Theorymentioning

confidence: 99%

Halting Planet Migration in the Evacuated Centers of Protoplanetary Disks

Kuchner

Lecar

2002

The Astrophysical Journal

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Precise Doppler searches for extrasolar planets find a surfeit of planets with orbital periods of 3-4 days and no planets with orbital periods less than 3 days. The circumstellar distance , where small grains in a proto-R 0 planetary disk reach sublimation temperatures (∼1500 K), corresponds to a period of ∼6 days. Interior to , R 0 turbulent accretion due to magnetorotational instability may evacuate the disk center. We suggest that planets with orbital periods of 3-4 days are so common because migrating planets halt once this evacuated region contains the sites of their exterior 2 : 1 Lindblad resonances.

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Toward an Astrophysical Theory of Chondrites

Cited by 499 publications

References 53 publications

Thermal desorption of circumstellar and cometary ice analogs

Thermal desorption of circumstellar and cometary ice analogs

Short-lived nuclei in the early Solar System: Possible AGB sources

Halting Planet Migration in the Evacuated Centers of Protoplanetary Disks

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