Title: The formation heritage of Jupiter Family Comet 10P/Tempel 2 as revealed by infrared spectroscopy Authors: L. Paganini, M. J. Mumma, B. P. Bonev, G. L. Villanueva, M. A. DiSanti, J. V. Keane, K. J. Meech
We present spectral and spatial information for major volatile species in Comet 10P/Tempel 2, based on high-dispersion infrared spectra acquired on UT 2010 July 26 (heliocentric distance Rh = 1.44 AU) and September 18 (Rh = 1.62 AU), following the comet's perihelion passage on UT 2010 July 04. The total production rate for water on July 26 was (1.90 ± 0.12) x 10^28 molecules s-1, and abundances of six trace gases (relative to water) were: CH3OH (1.58% ± 0.23), C2H6 (0.39% ± 0.04), NH3 (0.83% ± 0.20), and HCN (0.13% ± 0.02). A detailed analysis of intensities for water emission lines provided a rotational temperature of 35 ± 3 K. The mean OPR is consistent with nuclear spin populations in statistical equilibrium (OPR = 3.01 ± 0.18), and the (1{\sigma}) lower bound corresponds to a spin temperature > 38 K. Our measurements were contemporaneous with a jet-like feature observed at optical wavelengths. The spatial profiles of four primary volatiles display strong enhancements in the jet direction, which favours release from a localised vent on the nucleus. The measured IR continuum is much more sharply peaked and is consistent with a dominant contribution from the nucleus itself. The peak intensities for H2O, CH3OH, and C2H6 are offset by ~200 km in the jet direction, suggesting the possible existence of a distributed source, such as the release of icy grains that subsequently sublimed in the coma. On UT September 18, no obvious emission lines were present in our spectra, nevertheless we obtained a 3{\sigma} upper limit Q(H2O) < 2.86 x 10^27 molecules s-1.
Title: Ammonia and other parent molecules in comet 10P/Tempel 2 from Herschel/HIFI and ground-based radio observations Authors: N. Biver, J. Crovisier, D. Bockelée-Morvan, S. Szutowicz, D.C. Lis, P. Hartogh, M. de Val-Borro, R. Moreno, J. Boissier, M. Kidger, M. Küppers, G. Paubert, N. Dello Russo, R. Vervack, H. Weaver, HssO team
The Jupiter-family comet 10P/Tempel 2 was observed during its 2010 return with the Herschel Space Observatory. We present here the observation of the (J, K) = (1, 0)-(0, 0) transition of ammonia at 572 GHz in this comet with the Heterodyne Instrument for the Far Infrared (HIFI) of Herschel. We also report on radio observations of other molecules (HCN, CH3OH, H2S and CS) obtained during the 1999 return of the comet with the CSO telescope and the JCMT, and during its 2010 return with the IRAM 30-m telescope. Molecular abundances relative to water are 0.09%, 1.8%, 0.4%, and 0.08% for HCN, CH3OH, H2S, and CS, respectively. An abundance of 0.5% for NH3 is obtained, which is similar to the values measured in other comets. The hyperfine structure of the ammonia line is resolved for the first time in an astronomical source. Strong anisotropy in the outgassing is present in all observations from 1999 to 2010 and is modelled to derive the production rates.
Comet 10P (Tempel) in the constellation Cetus, 3:12 UT, 10th August, 2010.
Magnitude=10.1mag Best seen from 3.2h - 3.3h RA= 1h18m14 Dec=-10°58.0' (J2000) Distance to Sun= 1.47AU Distance to Earth= 0.66AU Elongation=122° hourly motion: dRA= 55.3"/h dDec=-27.8"/h
Comet 10P/Tempel can be observed in the Southeast part of the sky, located quite low above the horizon. The comet is now at a maximum (approximately 9.3) brightness and will remain so for the near future. The comet has already passed its perihelion, but observing is best planed for the period from 5 to 21 August. At this time the moon will be between the new moon and the first quarter phases.
Ephemeris
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag