Detection of CO Cameron band emission in comet P/Hartley 2 (1991 XV) with the Hubble Space Telescope

Weaver, Harold A.; Feldman, P. D.; McPhate, J. B.; A’Hearn, Michael F.; Arpigny, C.; Smith, T. E.

doi:10.1086/173732

Cited by 91 publications

(72 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our limit on CO production in GZ is similar to the estimated abundance of CO in the nucleus of Comets 1P/Halley (3.5%, Eberhardt 1998), Bradfield (C/1979 Y1) (3.5%, Feldman et al 1997), and Levy (C/1990 K1) (4.1-8.4%, Feldman et al 1997), and is significantly lower than the estimated CO abundances in comets Hyakutake (C/1996 B2) (∼14%, McPhate et al 1996; ∼20%, Biver et al 1999b;Mumma et al 1996 derived a preliminary value of 7%) and Hale-Bopp (∼10% at r ∼ 1 AU, according to Weaver et al 1999 andDiSanti et al 1999; ∼23% at r ∼ 1 AU, according to Biver et al 1999a). The CO abundance limit for GZ is somewhat larger than the abundance ratio observed in Comet Austin (C/1989 X1) (1.7%, Feldman et al 1997) and the upper limits derived for 103P/Hartley 2 (≤1.2%, Weaver et al 1994) and Shoemaker-Levy (C/1991 T2) (≤1.8%, Feldman et al 1997). Thus, CO in GZ is depleted relative to some comets, but GZ could have a CO abundance that is comparable to other comets considered "normal" in the A' Hearn et al (1995) compilation.…”

Section: Comentioning

confidence: 56%

“…Prior to the 1998 observations of GZ, Schwassmann-Wachmann 1 (SW1) was the only Jupiter-family comet 16 for which there had 16 Defined as comets having a Tisserand parameter with respect to Jupiter of T J > 2; see Levison and Duncan 1997. been a definite detection of CO, but SW1 never passes within 5.7 AU of the Sun. At least one short-period comet, 103P/Hartley 2 with a period of only 6.3 years, does not show any evidence for CO in its nucleus to a 3σ limit of ∼1% relative to H 2 O (Weaver et al 1994). Thus, searches for CO in other short-period comets may provide important insights into the ability of comets to retain this very volatile species that is so ubiquitous throughout the universe.…”

Section: Comentioning

confidence: 99%

See 1 more Smart Citation

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

Weaver¹,

Chin

Bockelée‐Morvan

et al. 1999

Icarus

View full text Add to dashboard Cite

We obtained high resolution (λ/δλ ∼ 10,000-20,000) infrared (IR) spectra of Comet 21P/Giacobini-Zinner (GZ) at five different wavelengths between 1.9 and 5.0 µm during 25-29 October 1998 using CSHELL at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. We also obtained a moderate resolution (λ/δλ ∼ 680) spectrum covering the wavelength range from 3.082 to 3.720 µm on 29 October 1998 using CGS4 at the United Kingdom Infrared Telescope (UKIRT) on Mauna Kea. Five rovibrational lines in three different vibrational bands of H 2 O were detected in the CSHELL spectra. Assuming that the rotational temperature was ∼50 K, we derive a H 2 O production rate of ∼2-3 × 10 28 molecules s −1 , which is ∼2 times smaller than the value derived from nearly simultaneous radio observations of OH. After continuum subtraction, the CGS4 spectrum displays significant excess flux that we attribute mainly to CH 3 OH fluorescence, and we derive that the CH 3 OH production rate was ∼2.7 × 10 26 molecules s −1 . The corresponding CH 3 OH/H 2 O relative abundance is ∼0.9-1.4%, which falls within the range of values observed in other comets, albeit at the low end. The CGS4 spectrum also has significant excess flux near 3.43 µm that is not explained by our CH 3 OH fluorescence model; a similar feature has been observed in several other comets, but its origin remains a mystery. We did not detect any excess emission near 3.28 µm, where some comets show a feature that may be associated with polycyclic aromatic hydrocarbons. We also searched for emissions from C 2 H 6 , CO, HCN, C 2 H 2 , and H 2 CO but did not detect any of these molecules. The 3σ upper limits for the abundances relative to H 2 O are 0.05-0.08% for C 2 H 6 , 2-3% for CO, 0.2-0.3% for HCN, 0.3-0.4% for C 2 H 2 , and 0.5-0.8% for H 2 CO, assuming that all species are parent molecules and that their rotational temperature in the coma is 50 K. C 2 H 6 is depleted by a factor of ∼15 or more compared to its relative abundance in Comets Hale-Bopp VOLATILES IN COMET 21P/GZ 483 (C/1995 O1) and Hyakutake (C/1996 B2); this depletion is similar to that observed for C 2 and C 3 from optical observations of GZ (A'Hearn et al. 1995) and suggests that the formation of volatile carbon-chain molecules was inhibited in GZ. We are unable to find any clear correlation between the C 2 H 6 and the C 2 and C 3 abundances in a sample of nine other comets, assuming that the residual emission near 3.35 µm in moderate resolution spectra of seven of the comets provides an accurate indicator of the C 2 H 6 abundance. However, this latter assumption is questionable and highlights the need to obtain high spectral resolution data in order to make accurate abundance measurements of C 2 H 6 .

show abstract

Section: Comentioning

confidence: 56%

Section: Comentioning

confidence: 99%

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

Weaver¹,

Chin

Bockelée‐Morvan

et al. 1999

Icarus

View full text Add to dashboard Cite

show abstract

“…Recently, the Akari infrared survey of 18 comets (both ECs and NICs) emphasized the importance of CO 2 , by demonstrating its high abundance (second only to H 2 O) in many comets (Ootsubo et al 2012). Only a few high-CO 2 comets were identified earlier (e.g., 103P/Hartley 2; Weaver et al 1994;Crovisier et al 1999).…”

Section: Introductionmentioning

confidence: 99%

C/2013 R1 (Lovejoy) at Ir Wavelengths and the Variability of Co Abundances Among Oort Cloud Comets

Paganini

Mumma

Villanueva

et al. 2014

ApJ

View full text Add to dashboard Cite

We report production rates, rotational temperatures, and related parameters for gases in C/2013 R1 (Lovejoy) using the Near InfraRed SPECtrometer at the Keck Observatory, on six UT dates spanning heliocentric distances (R h ) that decreased from 1.35 AU to 1.16 AU (pre-perihelion). We quantified nine gaseous species (H 2 O, OH * , CO, CH 4 , HCN, C 2 H 6 , CH 3 OH, NH 3 , and NH 2 ) and obtained upper limits for two others (C 2 H 2 and H 2 CO). Compared with organics-normal comets, our results reveal highly enriched CO, (at most) slightly enriched CH 3 OH, C 2 H 6 , and HCN, and CH 4 consistent with "normal", yet depleted, NH 3 , C 2 H 2 , and H 2 CO. Rotational temperatures increased from ∼50 K to ∼70 K with decreasing R h , following a power law in R h of −2.0 ± 0.2, while the water production rate increased from 1.0 to 3.9 × 10 28 molecules s −1 , following a power law in R h of −4.7 ± 0.9. The ortho-para ratio for H 2 O was 3.01 ± 0.49, corresponding to spin temperatures (T spin ) 29 K (at the 1σ level). The observed spatial profiles for these emissions showed complex structures, possibly tied to nucleus rotation, although the cadence of our observations limits any definitive conclusions. The retrieved CO abundance in Lovejoy is more than twice the median value for comets in our IR survey, suggesting this comet is enriched in CO. We discuss the enriched value for CO in comet C/2013 R1 in terms of the variability of CO among Oort Cloud comets.

show abstract

“…Owing to its frequent perihelion passages, the comet was relatively well-characterised prior to its 2010 apparition (see e.g. Arpigny et al 1993;Weaver et al 1994;Crovisier et al 1999;Colangeli et al 1999;Epifani et al 2001), although no information about the nucleus rotation was obtained.…”

Section: Introductionmentioning

confidence: 99%

Rotation-stimulated structures in the CN and C₃comae of comet 103P/Hartley 2 close to the EPOXI encounter

Waniak

Borisov

Drahus

et al. 2012

A&A

View full text Add to dashboard Cite

Context. In late 2010, a Jupiter family comet 103P/Hartley 2 was the subject of an intensive world-wide investigation. On UT October 20.7, the comet approached the Earth within only 0.12 AU, and on UT November 4.6 it was visited by the NASA EPOXI spacecraft. Aims. We joined this international effort and organized a ground-based observing campaign with three key goals to: (1) measure the parameters of the nucleus rotation in a time series of CN; (2) investigate the compositional structure of the coma by comparing the CN images with nightly snapshots of C 3 ; and (3) investigate the photochemical relation of CN to HCN, using the HCN data collected nearly simultaneously with our images. Methods. The images were obtained through narrowband filters using the two-meter telescope of the Rozhen National Astronomical Observatory. They were taken over four nights about the moment of the EPOXI encounter. Image processing methods and periodicity analysis techniques were used to identify transient coma structures and investigate their repeatability and kinematics. Results. We observe shells, arc-, jet-and spiral-like patterns that are very similar for the CN and C 3 comae. The CN features expanded outwards with the sky-plane projected velocities of between 0.1 to 0.3 km s −1 . A corkscrew structure, observed on November 6, evolved with a much higher velocity of 0.66 km s −1 . The photometry of the inner coma of CN shows variability with a period of 18.32 ± 0.30 h (valid for the middle moment of our run, UT 2010 Nov 5.0835), which we attribute to the nucleus rotation. This result is fully consistent with independent determinations around the same time by other teams. The pattern of repeatability is, however, imperfect, which is understendable given the suggested excitation of the rotation state, and the variability detected in CN correlates well with the cyclic changes in HCN, but only in the active phases. The identified coma structures, along with the snapshot of the nucleus orientation obtained by EPOXI, enable us to estimate the spin axis orientation. We obtain RA = 122 • , Dec = +16 • (epoch J2000.0), neglecting at this point the rotational excitation.

show abstract

Detection of CO Cameron band emission in comet P/Hartley 2 (1991 XV) with the Hubble Space Telescope

Cited by 91 publications

References 0 publications

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

C/2013 R1 (Lovejoy) at Ir Wavelengths and the Variability of Co Abundances Among Oort Cloud Comets

Rotation-stimulated structures in the CN and C₃comae of comet 103P/Hartley 2 close to the EPOXI encounter

Contact Info

Product

Resources

About

Detection of CO Cameron band emission in comet P/Hartley 2 (1991 XV) with the Hubble Space Telescope

Cited by 91 publications

References 0 publications

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

An Infrared Investigation of Volatiles in Comet 21P/Giacobini–Zinner

C/2013 R1 (Lovejoy) at Ir Wavelengths and the Variability of Co Abundances Among Oort Cloud Comets

Rotation-stimulated structures in the CN and C3comae of comet 103P/Hartley 2 close to the EPOXI encounter

Contact Info

Product

Resources

About

Rotation-stimulated structures in the CN and C₃comae of comet 103P/Hartley 2 close to the EPOXI encounter