<=== observer ===> "MBARLOW",\ "Barlow, M.J.",\ "Department of Physics & Astronomy",\ "University College London",\ "Gower Street",\ "",\ "WC1E 6BT",\ "London",\ "United Kingdom",\ " 44 713807160",\ " 44 713807145",\ "mjb@star.ucl.ac.uk" <=== proposal ===> "VEGA",1,3,\ {"circumstellar discs","dust properties"},\ {"LWS consortium","Gry, C.","Omont, A.","Walker, H.J.","Skinner, C."} <=== title ===> Spectroscopic Observations of Vega-Excess Systems <=== abstract ===> SCIENTIFIC ABSTRACT One of the major discoveries made by IRAS was finding the presence of a far-infrared excess around the standard star Vega (Alpha Lyrae) and around a number of other similar main sequence stars. The infrared excess has been interpreted as due to a disk of dust particles left over from the formation of such stars. The LWS will be used to study the dust disks around a number of these stars, in particular obtaining grating spectra to look for the 44 micron and 62 micron ice bands in emission from the cool disks. Fabry-Perot scans will also be obtained at the wavelengths of a number of ionic fine structure lines in the case of beta Pictoris, the only star in the sample for which the disk has been imaged and studied spectroscopically at non-infrared wavelengths. A LaTex file containing fuller details of this proposal is available from mjb@star.ucl.ac.uk. OBSERVATION SUMMARY Grating spectra are needed to look for dust features in the disks, and to investigate fully which lines are present. beta Pic will be observed with the FP as well, since optical and UV observations have already indicated the presence of emitting gas around this system. The FP observations will enhance the detectability of weaker lines seen against the dust continuum, as well as providing velocity (and thus dynamical) information about gas in the disk. 8.1 hours of LWS Guaranteed (spacecraft) time are allocated to this programme. If stars in the Orion-hole are observable (i.e. a Spring launch), 324.5 minutes will be used for full LWS grating scans of eight stars and 121.2 minutes will be used for full SWS fast grating scans of four stars. 51.1 minutes will be used for LWS FP scans of the spectrum of beta Pictoris at the wavelengths of six fine structure lines, these are: CII (157.7um), NII (121.9um), OI (63.2, 145.5um), FeIII (51.7um) and FeII (51.3um). If stars in the Sagittarius-hole are observable (i.e. an Autumn launch), 446.2 minutes will be used for full LWS grating scans of eleven stars and 30.3 minutes will be used for a full SWS fast grating scans of one star (complementary SWS scans of the remaining stars are being obtained by the SWS consortium). The Priority 1 LWS Guaranteed spacecraft time allocated to this programme is 3.21 hours if the Orion-hole is observable, or 3.38 hours if the Sgr-hole is observable. <=== scientific_justification ===> Stars mainly from the list of Walker and Wolstencroft (Publ. Astron. Soc. Pacific, 100, 1509, 1988) will be observed: Name Sp. IRAS Flux (Jy) 12 25 60 100 Tau1 Eri F6V 1.3 0.5 1.6 4.4 HD 34282 A0 0.8 1.7 10.8 10.6 HD 34700 G0 0.7 5.0 13.9 9.0 HD 35187 A2 6.3 11.0 7.3 4.8 Beta Pic A5V 4.1 9.4 18.7 10.8 HD 233517 A2 0.5 4.0 7.4 4.8 HD 98800 K5V 2.4 9.3 6.7 4.3 HD 135344 A0V 1.9 7.3 26.3 25.4 HD 139614 A7V 5.0 18.6 18.3 13.5 HD 141569 A0Ve 0.7 2.0 5.4 3.3 HD 142666 A3 9.3 10.3 6.7 5.3 HD 143006 G6e 1.0 3.4 6.4 4.7 HD 144432 F0V 8.2 8.6 5.2 3.2 HD 169412 B9V 3.5 19.8 28.9 22.7 Alpha Lyr A0V 29.8 9.4 9.0 7.5 Alpha PsA A3V 3.2 4.3 9.1 11.2 AOT LWS01: Full grating spectra: Wavelength coverage 43-196.7um No of samples per resolution element 4 Integration time per sample point 5 secs Total AOT time per star (fast scan) 37.2 mins Total S/C time per star 40.6 mins Total S/C time for LWS grating spectra (Orion-hole observable) 324.5 mins (Sgr-hole observable) 446.2 mins Name S/N(100um) S/N(60um) Priority Hole Tau1 Eri 33 8 3 HD 34282 74 52 3 O HD 34700 63 67 1 O HD 35187 34 35 2 O Beta Pic 76 91 1 O HD 233517 34 36 2 O HD 98800 30 32 1 HD 135344 178 127 1 S HD 139614 95 89 2 S HD 141569 26 23 3 S HD 142666 37 32 2 S HD 143006 33 31 3 S HD 144432 22 25 2 S HD 169142 159 140 1 S Alpha Lyr 53 44 1 S Alpha PsA 79 44 1 AOT LWS04: For beta Pic only, FP scans of the following fine structure lines will be made: CII 157.7um NII 121.9um OI 145.5um OI 63.2um FeIII 51.7um FeII 51.3um 4 sample points per FP resolution element Scans over +- 4 resolution elements (+- 120 km/s) per line 10 seconds integration time per sample point (1x10-15 W m-2 flux limit) Total FP AOT observation time = 50.8 mins Total S/C time for LWS FP spectra = 51.1 mins (Priority 2, Orion-hole) AOT SWS01: Eleven of the 16 targets are already scheduled to be observed in SWS Guaranteed time between 2.43-45 microns using the SWS01 AOT. We will observe the remaining five targets between 2.43-45um using the same SWS01 AOT, with a detector reset time of 2 seconds (speed code 2) and a resolving power of R/8, requiring 30.3 minutes of spacecraft time per object. The six stars to be observed in LWS Consortium time are: Name Hole Priority HD 34282 O 3 HD 34700 O 1 HD 35187 O 2 HD 233517 O 3 HD 143006 S 3 Wavelength coverage: 2.43-45um Total AOT time/star: 30.0 minutes Total S/C time/star: 30.3 minutes Total S/C time for SWS spectra (Orion-hole observable): 121.2 minutes Total S/C time for SWS spectra (Sgr-hole observable): 30.3 minutes SPACECRAFT TIME SUMMARY: Orion-hole observable (Spring launch) Sgr-hole observable (Autumn launch) Priority 1 time = 192.6 mins (38.8%) Priority 1 time = 202.8 mins (42.6%) Priority 2 time = 162.5 mins (32.7%) Priority 2 time = 121.7 mins (25.4%) Priority 3 time = 141.7 mins (28.5%) Priority 3 time = 152.0 mins (31.9%) Total S/C time = 496.8 mins Total S/C time = 476.5 mins Time distribution for spring launch targets: Team top 40% second 30% last 30% LWS : 11554 9752 8504 total : 11554 9752 8504 Time distribution for autumn launch targets: Team top 40% second 30% last 30% LWS : 12170 7302 9120 total : 12170 7302 9120 <=== autumn_launch_targets ===> 1, "LWS01", 3.0, "N", "Tau1 Eri", 02.71278, -18.78278, 1950, 0.,0.,1297,2 2, "LWS01", 3.0, "N", "Tau1 Eri off", 02.71278, -18.88278, 1950, 0.,0.,1137,0 3, "LWS01", 1.0, "N", "HD 98800", 11.32656, -24.50056, 1950, 0.,0.,1297,4 4, "LWS01", 1.0, "N", "HD 98800 off", 11.32656, -24.60056, 1950, 0.,0.,1137,0 5, "LWS01", 1.0, "N", "HD 135344", 15.21042, -36.97083, 1950, 0.,0.,1297,6 6, "LWS01", 1.0, "N", "HD 135344 off", 15.21042, -36.87083, 1950, 0.,0.,1137,0 7, "LWS01", 2.0, "N", "HD 139614", 15.62292, -42.33722, 1950, 0.,0.,1297,8 8, "LWS01", 2.0, "N", "HD 139614 off", 15.62292, -42.43722, 1950, 0.,0.,1137,0 9, "LWS01", 3.0, "N", "HD 141569", 15.78894, -03.77806, 1950, 0.,0.,1297,10 10, "LWS01", 3.0, "N", "HD 141569 off", 15.78894, -03.87806, 1950, 0.,0.,1137,0 11, "LWS01", 2.0, "N", "HD 142666", 15.89525, -21.88333, 1950, 0.,0.,1297,12 12, "LWS01", 2.0, "N", "HD 142666 off", 15.89525, -21.98333, 1950, 0.,0.,1137,0 13, "LWS01", 3.0, "N", "HD 143006", 15.92747, -22.81250, 1950, 0.,0.,1297,14 14, "LWS01", 3.0, "N", "HD 143006 off", 15.92747, -22.91250, 1950, 0.,0.,1137,23 15, "LWS01", 2.0, "N", "HD 144432", 16.06492, -27.58556, 1950, 0.,0.,1297,16 16, "LWS01", 2.0, "N", "HD 144432 off", 16.06492, -27.68556, 1950, 0.,0.,1137,0 17, "LWS01", 1.0, "N", "HD 169412", 18.35500, -29.80833, 1950, 0.,0.,1297,18 18, "LWS01", 1.0, "N", "HD 169412 off", 18.35500, -29.90833, 1950, 0.,0.,1137,0 19, "LWS01", 1.0, "N", "Alpha Lyr", 18.58739, +38.73583, 1950, 0.,0.,1297,20 20, "LWS01", 1.0, "N", "Alpha Lyr off", 18.58739, +38.83583, 1950, 0.,0.,1137,0 21, "LWS01", 1.0, "N", "Alpha PsA", 22.91486, -29.88778, 1950, 0.,0.,1297,22 22, "LWS01", 1.0, "N", "Alpha PsA off", 22.91486, -29.98778, 1950, 0.,0.,1137,0 23, "SWS01", 3.0, "N", "HD 143006", 15.92747, -22.81250, 1950, 0.,0.,1818,0 <=== spring_launch_targets ===> 1, "LWS01", 3.0, "N", "Tau1 Eri", 02.71278, -18.78278, 1950, 0.,0.,1297,1 2, "LWS01", 3.0, "N", "Tau1 Eri off", 02.71278, -18.88278, 1950, 0.,0.,1137,0 3, "LWS01", 3.0, "N", "HD 34282", 05.22725, -09.86417, 1950, 0.,0.,1297,4 4, "LWS01", 3.0, "N", "HD 34282 off", 05.22725, -09.96417, 1950, 0.,0.,1137,17 5, "LWS01", 1.0, "N", "HD 34700", 05.28350, +05.59472, 1950, 0.,0.,1297,6 6, "LWS01", 1.0, "N", "HD 34700 off", 05.28350, +05.69472, 1950, 0.,0.,1137,18 7, "LWS01", 2.0, "N", "HD 35187", 05.34908, +24.91528, 1950, 0.,0.,1297,8 8, "LWS01", 2.0, "N", "HD 35187 off", 05.34908, +24.81528, 1950, 0.,0.,1137,19 9, "LWS01", 1.0, "N", "Beta Pic", 05.76831, -51.08333, 1950, 0.,0.,1297,10 10, "LWS01", 1.0, "N", "Beta Pic off", 05.76831, -51.18333, 1950, 0.,0.,1137,21 11, "LWS01", 2.0, "N", "HD 233517", 08.31661, +53.24083, 1950, 0.,0.,1297,12 12, "LWS01", 2.0, "N", "HD 233517 off", 08.31661, +53.34083, 1950, 0.,0.,1137,20 13, "LWS01", 1.0, "N", "HD 98800", 11.32656, -24.50056, 1950, 0.,0.,1297,14 14, "LWS01", 1.0, "N", "HD 98800 off", 11.32656, -24.60056, 1950, 0.,0.,1137,0 15, "LWS01", 1.0, "N", "Alpha PsA", 22.91486, -29.88778, 1950, 0.,0.,1297,16 16, "LWS01", 1.0, "N", "Alpha PsA off", 22.91486, -29.98778, 1950, 0.,0.,1137,0 17, "SWS01", 3.0, "N", "HD 34282", 05.22725, -09.86417, 1950, 0.,0.,1818,0 18, "SWS01", 1.0, "N", "HD 34700", 05.28350, +05.59472, 1950, 0.,0.,1818,0 19, "SWS01", 2.0, "N", "HD 35187", 05.34908, +24.91528, 1950, 0.,0.,1818,0 20, "SWS01", 3.0, "N", "HD 233517", 08.31661, +53.24083, 1950, 0.,0.,1818,0 21, "LWS04", 2.0, "N", "Beta Pic", 05.76831, -51.08333, 1950, 0.,0.,3066,0