Millimetre continuum observations of comet C/2009 P1 (Garradd)

Boissier, J.; Bockelée‐Morvan, Dominique; Groussin, O.; Lamy, Philippe; Biver, N.; Crovisier, J.; Colom, P.; Moreno, R.; Jordá, L.; Piétu, V.

doi:10.1051/0004-6361/201321372

Cited by 9 publications

(8 citation statements)

References 27 publications

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“…A constant active area of approximately 75 km 2 can explain the water sublimation from the nucleus. As Garradd had a nucleus of radius <5.6 km (Boissier et al 2013) it must have had a very high active fraction (>20%). 3.…”

Section: Discussionmentioning

confidence: 99%

“…Boissier et al (2013) found an upper limit of 5.6 km based on millimeter observations of the continuum emission from the nucleus, which suggest a continuous active surface fraction of >20%. This would be a significant part of Garradd's surface and much higher than the active areas deduced for most comets for which reliable size estimates exist.…”

Section: Water Production From the Nucleus And In The Comamentioning

confidence: 96%

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THE EVOLVING ACTIVITY OF THE DYNAMICALLY YOUNG COMET C/2009 P1 (Garradd)

Bodewits

Farnham

A’Hearn

et al. 2014

ApJ

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We used the Ultraviolet-Optical Telescope on board Swift to observe the dynamically young comet C/2009 P1 (Garradd) from a heliocentric distance of 3.5 AU pre-perihelion until 4.0 AU outbound. At 3.5 AU pre-perihelion, comet Garradd had one of the highest dust-to-gas ratios ever observed, matched only by comet Hale-Bopp. The evolving morphology of the dust in its coma suggests an outburst that ended around 2.2 AU pre-perihelion. Comparing slit-based measurements and observations acquired with larger fields of view indicated that between 3 AU and 2 AU pre-perihelion a significant extended source started producing water in the coma. We demonstrate that this source, which could be due to icy grains, disappeared quickly around perihelion. Water production by the nucleus may be attributed to a constantly active source of at least 75 km 2 , estimated to be >20% of the surface. Based on our measurements, the comet lost 4 × 10 11 kg of ice and dust during this apparition, corresponding to at most a few meters of its surface. Even though this was likely not the comet's first passage through the inner solar system, the activity of Garradd was complex and changed significantly during the time it was observed.

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Section: Discussionmentioning

confidence: 99%

Section: Water Production From the Nucleus And In The Comamentioning

confidence: 96%

THE EVOLVING ACTIVITY OF THE DYNAMICALLY YOUNG COMET C/2009 P1 (Garradd)

Bodewits

Farnham

A’Hearn

et al. 2014

ApJ

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“…In the sample of comets with D/H determinations (or significant upper limits), only eight comets have a known nucleus size, most of them from spacecraft images or radar measurements . We also consider the hyperactive comet C/2009 P1 (Garradd), whose nucleus effective radius has been constrained to be < 5.6 km (Boissier et al 2013). The effective nucleus radius of comet 46P/Wirtanen is estimated to 0.63 km from radar imaging.…”

Section: Correlation Between the D/h Ratio And Hyperactivitymentioning

confidence: 99%

Terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets

Lis

Bockelée‐Morvan

Güsten

et al. 2019

A&A

104

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The D/H ratio in cometary water has been shown to vary between 1 and 3 times the Earth's oceans value, in both Oort cloud comets and Jupiter-family comets originating from the Kuiper belt. This has been taken as evidence that comets contributed a relatively small fraction of the terrestrial water. We present new sensitive spectroscopic observations of water isotopologues in the Jupiterfamily comet 46P/Wirtanen carried out using the GREAT spectrometer aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The derived D/H ratio of (1.61 ± 0.65) × 10 −4 is the same as in the Earth's oceans. Although the statistics are limited, we show that interesting trends are already becoming apparent in the existing data. A clear anti-correlation is seen between the D/H ratio and the active fraction, defined as the ratio of the active surface area to the total nucleus surface. Comets with an active fraction above 0.5 typically have D/H ratios in water consistent with the terrestrial value. These hyperactive comets, such as 46P/Wirtanen, require an additional source of water vapor in their coma, explained by the presence of subliming icy grains expelled from the nucleus. The observed correlation may suggest that hyperactive comets belong to a population of ice-rich objects that formed just outside the snow line, or in the outermost regions of the solar nebula, from water thermally reprocessed in the inner disk that was transported outward during the early disk evolution. The observed anti-correlation between the active fraction and the nucleus size seems to argue against the first interpretation, as planetesimals near the snow line are expected to undergo rapid growth. Alternatively, isotopic properties of water outgassed from the nucleus and icy grains may be different due to fractionation effects at sublimation. In this case, all comets may share the same Earth-like D/H ratio in water, with profound implications for the early solar system and the origin of Earth's oceans.

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“…As such, they have been the subject of extensive studies (we refer the reader to the comprehensive review by Levesque 2014), but no clear consensus has been reached in the community. Some investigations point toward a clear presence of a metallicity-dependence in the production of GRBs (e.g., Boissier et al 2013;Lunnan et al 2014), while others conclude that GRBs appear to be unbiased tracers of star formation (e.g., Fynbo et al 2008;Kohn et al 2015), and some highlight that discrimination between scenarios is challenging (e.g., Pontzen et al 2010;Laskar et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The Luminosity and Stellar Mass Functions of GRB Host Galaxies: Insight Into the Metallicity Bias

Trenti

Perna

Jiménez

2015

ApJ

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Long-Duration Gamma-Ray Bursts (GRBs) are powerful probes of the star formation history of the Universe, but the correlation between the two depends on the highly debated presence and strength of a metallicity bias. To investigate this correlation, we use a phenomenological model that successfully describes star formation rates, luminosities and stellar masses of star forming galaxies, and apply it to GRB production. We predict the luminosities, stellar masses, and metallicities of host galaxies depending on the presence (or absence) of a metallicity bias. Our best fitting model includes a moderate metallicity bias, broadly consistent with the large majority of the long-duration GRBs in metal-poor environments originating from a collapsar (probability ∼ 83%, with [0.74; 0.91] range at 90% confidence level), but with a secondary contribution (∼ 17%) from a metal-independent production channel, such as binary evolution. Because of the mass-metallicity relation of galaxies, the maximum likelihood model predicts that the metal-independent channel becomes dominant at z 2, where hosts have higher metallicities and collapsars are suppressed. This possibly explains why some studies find no clear evidence of a metal-bias based on low-z samples. However, while metallicity predictions match observations well at high redshift (z 2), there is tension with low redshift observations, since a significant fraction of GRB hosts are predicted to have (near) solar metallicity. This is in contrast to observations, unless obscured, metal-rich hosts are preferentially missed in current datasets, and suggests that lower efficiencies of the metal-independent GRB channel might be preferred following a comprehensive fit that includes metallicity of GRB hosts from complete samples. Overall, we are able to clearly establish the presence of a metallicity bias for GRB production, but continued characterization of GRB host galaxies is needed to quantify its strength. Tabulated model predictions are available in electronic format.

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Millimetre continuum observations of comet C/2009 P1 (Garradd)

Cited by 9 publications

References 27 publications

THE EVOLVING ACTIVITY OF THE DYNAMICALLY YOUNG COMET C/2009 P1 (Garradd)

THE EVOLVING ACTIVITY OF THE DYNAMICALLY YOUNG COMET C/2009 P1 (Garradd)

Terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets

The Luminosity and Stellar Mass Functions of GRB Host Galaxies: Insight Into the Metallicity Bias

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