__________________________________________________________________________ T H E O L E R O E M E R M E S S E N G E R _______________________________________________ JJJJ C G JJJJJJ I E JJJJ __________________________________________________________________________ Newsletter of the International Jupiter Watch Satellite Discipline E-mail issue 6 January 27th, 1994 Editor and Discipline Leader: John Spencer Voice: (602) 774-3358 Lowell Observatory Fax: (602) 774-6296 1400 W. Mars Hill Rd. Internet: spencer@lowell.edu Flagstaff, AZ 86001 ------------------------------------------------------------------------------ EDITORIAL COMMENTS This issue includes miscellaneous news of observation and publication plans, plus some new information on the comet impact predictions, and information on how to participate in a special bulk order of filters for impact observations. I'd like to include a more complete list of new publications and preprints, and 1994 observing plans. Please send me the information! ------------------------------------------------------------------------------ SHOEMAKER-LEVY IMPACT The following memo appeared on the impact bulletin board recently, (telnet to "pdssbn.astro.umd.edu" and log on as "c1993e") with the latest predictions of impact times. There's no significant change since the times issued in December, but the uncertainty is now quoted at only about 40 minutes. Note, by the way, that fragment P is double... Predicted Impact Parameters for Fragments of P/Shoemaker-Levy 9 --------------------------------------------------------------- Predictions as of 1994 January 19 P.W. Chodas, D.K. Yeomans and Z. Sekanina JPL/Caltech The impact parameters for fragments E, G, H, K, L, Q, R, S, and W were obtained from independent orbit solutions for those fragments. Impact parameters for the other fragments were computed from orbit solutions obtained by applying a tidal disruption model to the orbit for fragment Q, and matching the relative astrometry. The method is outlined in our preprint (Sekanina, Chodas, and Yeomans). The impact dates below include the light time to the Earth. The probability that a given Galilean satellite will be in view of an impact is given in terms of sigmas: 0 indicates a probability of less than 68%, 1 indicates 69-95%, 2 indicates 96-99%, and 3 indicates a probability greater than 99%. For example, the probabilities that Io, Europa, and Callisto will be in view of the fragment Q impact are all greater than 99%. The one-sigma uncertainties specified on the bottom line are average values obtained from Monte Carlo analyses for the eight fragments having the best orbit solutions. The same analyses computed the probability that the fragments will in fact impact Jupiter is > 99.99%, and the probability that any will impact on the near side as viewed from the Earth is < 0.2%. ------------------------------------------------------------------------------- Fragment Impact Date Jovicentric Meridian Angle Angle Probability of (July) Latitude Angle S-F-J E-J-F viewing impact U.T. (deg) (deg) (deg) (deg) Io Eu Ga Ca ------------------------------------------------------------------------------- A = 21 16.81 -43.26 64.43 73.95 98.73 0 3 3 3 B = 20 17.11 -43.34 64.73 74.18 98.49 3 3 3 3 C = 19 17.27 -43.37 64.90 74.30 98.36 3 2 3 3 D = 18 17.48 -43.42 65.11 74.46 98.20 3 0 3 3 E = 17 17.60 -43.91 59.66 70.99 101.90 1 0 3 3 F = 16 18.01 -43.53 65.65 74.87 97.78 0 0 3 3 G = 15 18.31 -43.90 65.32 74.77 97.93 0 0 3 3 H = 14 18.81 -43.85 66.24 75.38 97.28 3 0 0 3 J = 13 19.09 -43.74 66.77 75.71 96.92 3 0 0 3 K = 12 19.43 -43.99 67.21 76.09 96.56 0 3 0 3 L = 11 19.94 -44.15 67.51 76.34 96.31 0 3 0 3 M = 10 20.23 -43.92 67.99 76.60 96.01 0 3 0 3 N = 9 20.41 -43.95 68.18 76.73 95.87 0 3 0 3 P = 8 20.62 -43.97 68.40 76.89 95.71 3 3 0 3 Q = 7 20.81 -44.29 67.35 76.27 96.39 3 3 0 3 R = 6 21.30 -44.14 79.28 79.28 93.26 1 0 0 3 S = 5 21.66 -44.62 68.71 77.30 95.37 0 0 0 3 T = 4 21.75 -44.10 69.63 77.77 94.80 0 0 0 3 U = 3 21.88 -44.11 69.77 77.88 94.69 0 0 0 3 V = 2 22.18 -44.14 70.09 78.11 94.46 0 0 0 3 W = 1 22.32 -44.20 69.92 78.00 94.57 2 0 0 3 ------------------------------------------------------------------------------- Approximate Uncertainty 0.03 0.6 2.5 1.6 1.7 (1-sigma) ------------------------------------------------------------------------------- Notes: 1. Two fragment designations are given: the letter designation is that used in our preprint (Sekanina, Chodas, and Yeomans); the numerical designation is that used by Jewitt. Q=7 is the brightest. 2. The meridian angle is the Jovicentric longitude of impact measured from the midnight meridian towards the morning terminator. 3. Angle S-F-J is the Sun-Fragment-Jupiter angle at impact; values less than 90 deg indicate a nightside impact: all impacts are on the nightside. 4. Angle E-J-F is the Earth-Jupiter-Fragment angle at impact; values greater than 90 deg indicate a farside impact: all impacts are on the farside as viewed from Earth, with the later impacts being closer to the limb. 5. The predictions for fragments E and R are more uncertain than those for G, H, K, L, Q, S, and W, because the orbits are less well-determined. 6. The most recent measuremenets included in the orbit solutions were taken on Jan. 4 for fragments E and R, Jan. 9 for fragment S, and Jan. 10 for fragments G, H, K, L, Q, and W. ------------------------------------------------------------------------------ ORDERING FILTERS FOR THE SHOEMAKER-LEVY IMPACT I have decided to go with Omega Optical for the visible / near-IR impact filter order. Their prices are significantly cheaper than Barr and they have been much more helpful in putting the deal together. People have been happy with their quality in the past. The biggest concern with Omega was the delivery time of 18 weeks after receipt of order, but now we are in the queue they expect to be able to do better than this, and we can put a higher priority on filters like the 8900 A CH4 and nearby continuum filters which seem to be needed soonest. So delivery of most of the filters by May is probable. Glenn Orton (go@orton.jpl.nasa.gov) is still the contact person for filters at wavelengths beyond 2.5 microns. Below is a list of general and specific filter specifications, along with my identifying code for each filter, my understanding of its purpose, and an estimated price for various sizes. These prices are estimates because until all orders are in we won't know the total quantity, and the more filters are made the cheaper each one is. The prices are based on the numbers of filters requested so far, and may thus decrease if we get more orders. OMEGA OPTICAL ADDRESS: Omega Optical 3 Grove Street PO Box 573 Brattleboro, VT 05301 (802) 254-2690 Fax: 254-3937 The contact person there is Peter Hetzel, who is very helpful. MY ADDRESS: John Spencer Lowell Observatory 1400 W. Mars Hill Rd. Flagstaff, AZ 86001 Work: (602) 774-3358 Home: 773-9260 Fax: 774-6296 spencer@lowell.edu LOGISTICS OF THE FILTER ORDER 1) Please contact me BEFORE FEBRUARY 7th with a list containing the following information for EACH filter that you need: i) Filter wavelength, FWHM, and (as a check) my designation code for the filter. ii) Size needed (specify inches or cm!), and whether square or circular. You aren't restricted to the sizes given in the list: those are just to give an idea of prices. iii) Quantity needed. iv) The name of the contact person and the institution that will pay for them (not essential, but it will help me keep track). Please do this even if you have already told me what you need- otherwise I'll have to go through my old mail and try to figure out how definite all the previous numbers I've received were, and I'm likely to make mistakes. If you need a filter that's not on the list, tell me that too, being as specific as you can: it can probably be included in the order also though I won't be able to give you a price. You might want to contact Peter Hetzel at Omega directly for information in this case, but still submit the order through me. I will consolidate the orders and submit them to Omega, who will then start work. 2) Though the numbers you send me should be as accurate as possible, it will still be possible to add extra filters later if that wavelength batch hasn't already been cooked up, and even extra wavelengths can be added though they will be lower down in the priority list. So don't delay contacting me with your order if you have some lingering possibility of later deciding that you need extra filters. If you do order extra filters, please do so through me (so we can keep everything straight). 3) Send a purchase order directly to Omega (not to Lowell!) for the filters you specified in your order(s) to me. Omega will ship the filters directly to you, but not until they get your PO. GENERAL FILTER SPECIFICATIONS Maximum thickness 0.25 inches Optical quality: substrate of selected commercial grade, no visible striae or bubbles Surface Flatness: 1/2 wave or better Surface parallelism: 1 arcmin or better These specifications constitute "Image quality" Center wavelength tolerance: +/- 10% of the FWHM FWHM tolerance: +/- 10% of the FWHM System speed: f/7 or slower Effective refractive index: 2 Anti-reflection coating: Multi-layer fluoride, both surfaces Pinhole restriction: None visible to naked eye in viewing chamber defined by Mil-O-13830A Surface quality: 60/40 scratch/dig per Mil-O-13830A Tolerance on outside dimension: +0, -0.2 mm Edge treatment of 1" and 2" diameter filters: Hermetically sealed in anodised aluminum ring. Edge treatment of other filters: Chamfered, painted, hermetically sealed Edge marking: Customer name, Omega part number, and trace code Minimum clear aperture: 4mm less than nominal outside dimension Documentation: Spectrophotometric trace of pass band in %T, and of the attenuation regions in optical density For wavelengths < 1 micron: Blocking to 1e-5 or better: 0.3 - 1.2 microns Wavelengths good at 20 C For wavelengths > 1 micron: AVERAGE blocking to 1e-5 or better: 0.3 - 2.5 microns Maximum out-of-band transmission, 0.3-2.5 microns: 1e-4. Wavelengths good at 77 K SPECIFICATIONS FOR EACH FILTER ---------------------------------------------------------------- Wavelength < 1 micron: wavelengths given in Angstroms: Designation: CA Wavelength: Standard Astronomical B Prices: 2" square $225 1" diameter $131 Designation: CM Wavelength: Standard astronomical V Prices: 1" diameter $131 Designation: CJ Wavelength: 6040 FWHM: 50 Purpose: Continuum Prices: 2" diameter $435 Designation: CK Wavelength: 6184 FWHM: 20 Purpose: CH4 Prices: 2" square $484 2" diameter $435 1.5" diameter $435 1" diameter $281 Designation: CC Wavelength: 6199 FWHM: 40 Purpose: H20+ Prices: 1" diameter $304 Designation: CB Wavelength: 6563 FWHM: 30 Purpose: H-alpha Prices: 1" diameter $304 Designation: CD Wavelength: Standard Astronomical R Prices: 2" square $225 1" diameter $131 1.50" diameter $191 Designation: CN Wavelength: 7251 FWHM: 100 Purpose: Broadband CH4 Prices: 1" diameter $304 Designation: CE Wavelength: 7270 FWHM: 20 Purpose: CH4 band (IJW set) Prices: 2" square $435 2" diameter $435 1.5" diameter $435 1" diameter $338 Designation: CO Wavelength: 7498 FWHM: 150 Purpose: Broadband continuum Prices: 1" diameter $304 Designation: CF Wavelength: 7500 FWHM: 50 Purpose: Continuum (IJW set) Prices: 2" square $435 2" diameter $435 1.5" diameter $435 1" diameter $338 Designation: CG Wavelength: 8290 FWHM: 50 Purpose: Approx. continuum, hydrogen dipole (?) (IJW set) Prices: 2" square $484 2" diameter $435 1" diameter $218 Designation: CI Wavelength: 8900 FWHM: 300 Purpose: CH4, broadband for near-Jupiter work Prices: 2" square $330 1.5" diameter $435 1" diameter $296 Designation: CH Wavelength: 8930 FWHM: 50 Purpose: CH4 (IJW set) Prices: 4" square $750 2" square $484 2" diameter $435 1.5" diameter $435 1" diameter $218 Designation: CL Wavelength: 9450 FWHM: 50 Purpose: Continuum Prices: 2" diameter $435 Designation: CP Wavelength: 9482 FWHM: 200 Purpose: Broadband continuum Prices: 2" diameter $435 ------------------------------------------------------- Wavelength > 1 micron: wavelengths given in microns Designation: NB Wavelength: 1.50 FWHM: 0.05 Purpose: NH3 Prices: 1" diameter $304 Designation: NC Wavelength: 1.58 FWHM: 0.01 Purpose: Narrowband continuum Prices: 1" diameter $281 Designation: ND Wavelength: 1.70 FWHM: 0.05 Purpose: CH4 Prices: 1" diameter $296 Designation: NE Wavelength: 2.11 FWHM: 0.05 Purpose: Pressure-induced H2 Prices: 1" diameter $304 Designation: NF Wavelength: 2.30 FWHM: 0.20 Purpose: CH4 broadband (for near-Jupiter studies) Prices: 1" diameter $304 Designation: NG Wavelength: 2.35 FWHM: 0.06 Purpose: CH4 narrowband (Jupiter minimum reflectance) Prices: 1" diameter $304 ------------------------------------------------------------------------------ ICY GALILEAN SATELLITES CONFERENCE San Juan Capistrano Research Institute, February 1-3, 1994 Coming up next week! Hope to see many of you there... There will be a special session on Thursday morning discussing plans for groundbased support of Galileo icy satellite observations. While not so critical as for Io, there may be important things to be done from the ground during the mission. Bring your ideas to the meeting, or send them to me beforehand... ------------------------------------------------------------------------------ OBSERVING PLANS Spencer, Rayner, and Person observed a Jupiter eclipse and occultation of Io on January 6th from 3-5 microns at the IRTF, with NSFCAM. Loki was undergoing a bright eruption: hopefully it will keep it up for a while... Jody Wilson and Ann Sprague are taking high resolution spectra in sodium D-line and oxygen ([OI] 6300) of near-Io cloud. January 23-27 and 30th. Melissa McGrath has an IUE run in early February to look at the Io torus. Bob Howell at WIRO (Wyoming): 5 micron speckle observations of Io, plus Jupiter eclipses and occultations. Dates: Feb. 23 - Mar. 4 UT (so the nights of 22-03 local time) Mar. 29 - Apr. 1 UT (so the nights of 28-31 local time) He hopes to have more time in April - June, but that won't be scheduled till sometime in March. Jay Goguen has IRTF time April 28-29. Nick Schneider, Linda Sauter, and John Spencer will use CSHELL on the IRTF on May 27 and 29 to look for 1-micron emission from neutral sulfur in Io's atmosphere. Spencer will again use NSFCAM on the IRTF to monitor the Io volcanism on June 19 and 21. Spencer hopes to investigate the Ganymede 5770 and 6290 A absorption bands in more detail in April 1994, using a CCD spectrograph at Lowell. Tony Mallama and Douglas Caprette in Maryland, Donald Collins and Michal Vojticek-Lom in North Carolina, and James Park and Peter Nelson in Australia, will once again make CCD timings of eclipses of all the Galilean satellites. ------------------------------------------------------------------------- PUBLICATIONS IN (OR EMERGED FROM) THE PIPELINE This is a fragmented list assembled in a hurry, and isn't complete. If you have an article to publicise, let me know and I'll include it here. Hammel H.B., RM Nelson (1993) Bright Flash on Jupiter in 1983 Nature 366, 117. Shelus PJ, AL Whipple, GF Benedict (1993) Astrometric Observations of the Faint Outer Satellites of Jupiter During the 1993 Opposition Astronomical Journal 106, 2573-2574 Mallama A, DS Caprette (1993) Measurement of the Polar Radius of Jupiter Icarus 105, 307-309 Beatty, K., and D. Levy (1994). Article on the comet impact. Sky and Telescope, January 1994. J.R. Spencer, B.E. Clark, L.M. Woodney, W.M. Sinton, and D. Toomey (1994). Io Hot Spots in 1991: Results from Europa Occultation Photometry and Infrared Imaging. Icarus, in press Johnson, R.E. (1994). Formation of Na-containing molecular ions at Io. Submitted to Icarus Io special issue. -----------------------------------------------------------------------