NASA Infrared Telescope Facility (IRTF) Alan Tokunaga 1
Current status The 3-m IRTF is operated by the University of Hawaii under a a 5-year contract with NASA. 50% of the IRTF time is for solar system research and 50% is for astrophysics. We typically get about 50 proposals each semester from the planetary community. Note that many proposals are for partial nights and for multiple observing periods. Most of our observers do their work remotely. 2
Uniqueness for NASA Missions and Planetary Astronomy: A dedicated facility for planetary astronomers. Timely ground-based observations in support of planetary missions. Training students and a platform for new instruments. 3
Uniqueness for NASA Missions and Planetary Astronomy: A dedicated facility for planetary astronomers. Timely ground-based observations in support of planetary missions. Training students and a platform for new instruments. Priority on time critical planetary observations: Unexpected mission requirements. Required solar phase angle, specific planetary features, new comets, new Near-Earth Objects, occultations, daytime observations of comets and planets. 4
Uniqueness for NASA Missions and Planetary Astronomy: A dedicated facility for planetary astronomers. Timely ground-based observations in support of planetary missions. Training students and a platform for new instruments. Flexible scheduling and remote observing: Observing periods as short as 1 hour. Multiple short observations possible with remote observing. Unique instruments: SpeX/MORIS Low-to-moderate spectral resolution for 0.8-5 µm with simultaneous visible imager. TEXES R=100,000 spectral resolution at 8-25 µm. ishell R=70,000 spectral resolution at 1.2-5.3 µm. MIRSI 8-25 µm camera. 5
Up to four IRTF facility and visitor instruments are mounted at the focal plane of the telescope. 6
This photo shows the back end of the instrument mount. The CSHELL instrument is at the center location and SpeX is on the left in a standby position. Instruments can be changed during the night for operational flexibility. 7
Uniqueness for NASA Missions and Planetary Astronomy: A dedicated facility for planetary astronomers. Timely ground-based observations in support of planetary missions. Training students and a platform for new instruments. Classical observing and visitor instruments welcomed. Remote observing expands opportunity for training students. Unique visitor instruments include TEXES, BASS, HIPWAC, CELESTE, and are available for use by the community with PI approval. List of instruments at: http://irtfweb.ifa.hawaii.edu/facility/ 8
Distribution of Allocated Observing Time (2015B) 9
Citations to observatories, DPS 2013" 10
Examples)of)scientific)results) NEO)studies:)demonstration)of)target)of) opportunity)observations.))24>48)hour)advance) notification.)) Long)duration)synoptic)studies:)example)of)a)13>year) study)of)pluto s)ices.) High)spectral)resolution:))example)of)science)to)be) done)with)ishell.) 11
Asteroid 2014 RC SpeX spectrum in 1 hour. (Vmag = 17) Slit viewer image 2014 Sept 6; 11:00 UT 12
~20 m diameter R. P. Binzel, D. Polishook (MIT); S. J. Bus (U. Hawaii) 13
Asteroid 2014 RC Ridiculously rapid rotation: 16 second period (!) Derived from saved MORIS images (2.5 sec exp.) Confirmed by radar and other observers. Implications for studies of strength / cohesion. Unknown: How to spin up so fast?? 14
Smallest Near-Earth Asteroid Just two days after its discovery on October 11, 2015, asteroid 2015 TC25 made a very close pass by the Earth at a distance of about 111,000 km, or 29% of the distance to the Moon. 2015 TC25 is very similar to a rare class of iron-poor stony meteorites, called Aubrites. 2015 TC25, which rotates once every 133 seconds, is only about 2 meters in diameter, making it the smallest asteroid ever mineralogically characterized with a ground-based telescope. Aubrite NASA IRTF Spectrum 6 feet Reddy et al. in prep. President Obama for scale 2015 TC25 (artist s concept)
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Pluto spectrum taken with IRTF/SpeX 17
CH ice 4 18
N band 2 CO band 19
Ancient oceans on Mars Villanueva et al. 2015 20
3.55 mic Synthetic spectrum of Mars with the spectral coverage of NIRSPEC, CRIRES, and CSHELL shown. Observations of HDO and H2O were used to establish the quantity of water on Mars 4.1-4.5 billion years ago. 2.98 mic 21
ishell 1-5 micron immersion grating cross-dispersed echelle spectrograph R = λ/δλ = 70,000 with a 0.35 arc-sec slit Uses a 2Kx2K H2RG array for the spectrograph; a 1Kx1K InSb array for the slit viewer Planned for open use during semester 2016B 11/15/15 22
Spectral coverage of ishell in the L-band with a spectral resolving power of 70,000. 23
Proposals due: 01 April, 01 October http://irtfweb.ifa.hawaii.edu/ Poster 312.20 11/15/15 24