# # Program information file # PROGRAM_ID 2023B055 PROGRAM_TITLE SpeX observations of 62P/Tsuchinshan 1, 103P/Hartley 2, and 144P/Kushida: Exploring the overall coma composition of comets PROGRAM_INV1 Ron Vervack PROGRAM_INV2 Neil Dello Russo PROGRAM_INV3 Boncho Bonev PROGRAM_INV4 Michael DiSanti PROGRAM_INV5 Erika Gibb PROGRAM_SCICAT comets PROGRAM_ABSTRACT_BEG Semester 2023B represents an excellent opportunity to observe three Jupiter-family comets [JFCs]: 62P/Tsuchinshan 1, 103P/Hartley 2, and 144P/Kushida. Our proposed study emphasizes three science objectives for which the IRTF/SpeX combination is ideal: [1] sample overall gas emission by observing strong but overlapping emissions between 2.8 and 4.2 um, [2] sample the continuum from 0.7 to 4.2 um to investigate the dust environment, and [3] implement building a database of moderate-resolution comet spectra. Owing to its large spectral grasp, SpeX enables a survey of the overall 'organics' region between 3.2-3.6 um simultaneously with other gas emissions [e.g., H2O]. At the same time, measurements of the underlying continuum provide information on cometary dust grains and ice signatures, both of which are important in understanding formation conditions in the solar nebula. Because the resolution and wavelength grasp of JWST/NIRSpec and of most near-IR spacecraft instruments are comparable to [or less than] those of SpeX, a long-term database of SpeX comet observations will aid in the analyses and interpretation of such data, thereby addressing the IRTF's role in supporting NASA missions. SpeX comet observations could also potentially expand the range of comets for which meaningful near-IR probes of coma chemistry are possible. Specific reasons for targeting these three comets are that 62P recently experienced encounters with Jupiter that have lowered its perihelion distance, 103P is a previous [and potentially future] mission target, and 144P is a here-to-fore unobserved JFC that will add to our knowledge of this underrepresented dynamical class. To achieve our objectives, we will use the LXD-short and SXD settings of SpeX. Guidedog is sufficient for guiding, so MORIS is not needed. The 0.8 arcsec slit will be used to balance throughput and resolution. Our observing request includes five 6-hour blocks [62P and 103P pre-/post-perihelion, 144P pre-perihelion], for a total of 30 hours. PROGRAM_ABSTRACT_END