<i>AKARI</i>NEAR-INFRARED SPECTROSCOPIC SURVEY FOR CO<sub>2</sub>IN 18 COMETS

Ootsubo, Takafumi; Kawakita, Hideyo; Hamada, Saki; Kobayashi, Hitomi; Yamaguchi, Mitsuru; Usui, Fumihiko; Nakagawa, Takao; Ueno, Munetaka; Ishiguro, Masateru; Sekiguchi, T.; Watanabe, Jun; Sakon, Itsuki; Shimonishi, Takashi; Onaka, Takashi

doi:10.1088/0004-637x/752/1/15

Cited by 177 publications

(202 citation statements)

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“…For fainter comets, where high-resolution spectroscopy is impossible, or where there is too low radial velocity with respect to Earth, observations from space telescopes are necessary. Some of the most sensitive observations were made with the Akari satellite, with detections of the 2.7 µm ν 3 band of water at Q = 1.2 × 10 27 mol s −1 made in comet 22P/Kopff when it was at 2.4 au from the Sun (Ootsubo et al 2012). This band was also observed in bright comets in both imaging and spectroscopy by the International Space Observatory (ISO) satellite (Colangeli et al 1999;Crovisier et al 1997) and the Deep Impact spacecraft ).…”

Section: Infrared and Sub-mm/radio Emission Featuresmentioning

confidence: 99%

The Main Belt Comets and ice in the Solar System

Snodgrass

Agarwal

Combi

et al. 2017

Astron Astrophys Rev

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We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies.

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Section: Infrared and Sub-mm/radio Emission Featuresmentioning

confidence: 99%

The Main Belt Comets and ice in the Solar System

Snodgrass

Agarwal

Combi

et al. 2017

Astron Astrophys Rev

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“…The most substantial set of gas production rate observations come from Schleicher (2006), who presents narrow-band photometry taken around the 1982 and 1996 perihelion passages, reaching a maximum distance of r = 1.86 AU outbound, and also reviews measurements from other authors. Ootsubo et al (2012) measured water and CO 2 production rates using the Akari satellite when 67P was at r = 1.8 AU inbound in 2008. There is considerable scatter in these measurements, attributed to rotational variability by Schleicher (2006), but in general water production rate is found to peak at Q ≈ 10 28 molecules s −1 around a month after perihelion.…”

Section: Gas Productionmentioning

confidence: 99%

Beginning of activity in 67P/Churyumov-Gerasimenko and predictions for 2014–2015

Snodgrass

Tubiana

Bramich

et al. 2013

A&A

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Context. Comet 67P/Churyumov-Gerasimenko was selected in 2003 as the new target of the Rosetta mission. It has since been the subject of a detailed campaign of observations to characterise its nucleus and activity. Aims. Here we present previously unpublished data taken around the start of activity of the comet in 2007/8, before its last perihelion passage. We constrain the time of the start of activity, and combine this with other data taken throughout the comet's orbit to make predictions for its likely behaviour during 2014/5 while Rosetta is operating. Methods. A considerable difficulty in observing 67P during the past years has been its position against crowded fields towards the Galactic centre for much of the time. The 2007/8 data presented here were particularly difficult, and the comet will once again be badly placed for Earth-based observations in 2014/5. We make use of the difference image analysis (DIA) technique, which is commonly used in variable star and exoplanet research, to remove background sources and extract images of the comet. In addition, we reprocess a large quantity of archival images of 67P covering its full orbit, to produce a heliocentric lightcurve. By using consistent reduction, measurement and calibration techniques we generate a remarkably clean lightcurve, which can be used to measure a brightnessdistance relationship and to predict the future brightness of the comet. Results. We determine that the comet was active around November 2007, at a pre-perihelion distance from the Sun of 4.3 AU. The comet will reach this distance, and probably become active again, in March 2014. We find that the dust brightness can be well described by A f ρ ∝ r −3.2 pre-perihelion and ∝ r −3.4 post-perihelion, and that the comet has a higher dust-to-gas ratio than average, with log(A f ρ/Q(H 2 O)) = −24.94 ± 0.22 cm s molecule −1 at r < 2 AU. A model fit to the photometric data suggests that only a small fraction (1.4%) of the surface is active.

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“…Space-based observations show that CO 2 is the dominant volatile for most distant comets (Bauer et al 2015, Ootsubo et al 2012, Reach et al 2013, and many models incorporate it as a likely driver of distant activity (Prialnik et al 2004, Bar-Nun & Laufer 2013. Unfortunately, CO 2 is difficult to observe from the ground, and thus, we focused on carbon monoxide emission, which is readily observable in cold cometary gas through its rotational transitions (Crovisier & Le Bourlot 1983).…”

Section: Introductionmentioning

confidence: 99%