Request for Director's Discretionary Time for a peculaie supernova/impostor. The object may not stay bright in the UV for long. Assigned ID: 2029 ----- Attempting Submission 1 (Sun Dec 04 17:58:47 GMT 2011) ----- This is our "safe" plan which uses only STIS/CCD. An alternative plan with STIS/MAMA gives better coverage in the FUV below 2100 AA; we will try to send you a copy later tonight. Originally we hoped to use COS but it has more problems than we hoped. ----- Attempting Submission 1 (Wed Dec 14 04:59:12 GMT 2011) ----- HST Phase II Proposal 12785 (stis-ccd-v015.apt) successfully submitted. ----- Attempting Submission 2 (Wed Dec 14 07:01:10 GMT 2011) ----- We will use only one of these alternative orbit plans: either CCD or MAMA. Both are included because of need for brightness review for MAMA. If it passes examination, the MAMA plan is probably better. [kd] The Strange Supernova or Supernova Impostor SN2011ht SN2011ht may be a peculiar supernova or new type of supernova impostor. In either case, the dramatic increase in its UV flux, combined with its exotic visual spectrum and strong blue continuum, are remarkable and not easy to explain. This object has a supernova-like luminosity with a spectrum that resembles a hot, dense wind, but its steep continuum slope and UV flux are not characteristic of a dense wind, even a very hot one. If the wind is opaque, how can it produce such a steep continuum, and if it isn't, what produces the continuum with the SN-like brightness? To solve the paradox of SN2011ht's spectrum and peculiar eruption, we must look where it is emitting most of its energy, the ultraviolet. Emission and absorption lines in the near-UV will provide badly needed diagnostics on its temperature and other parameters. We are requesting one orbit of Director's Discretionary time to obtain a UV spectrum of SN2011ht.
TBD HOT STARS 0 false 0.0 0.0 false false false false SUPPORTED EXT-STAR SUPERNOVA TYPE II J2000 Flambda=roughly 1e-14 in range 2000--3000 AA, based on Swift data. Decreasing about 0.05 magn/day. COS/NUV Spectroscopic No No G230L 2635 COS/NUV Spectroscopic No No G230L 2950 COS/NUV Spectroscopic No No G230L 3000 COS/NUV Spectroscopic No No G230L 3360 COS/FUV Spectroscopic No No G140L 1280 POS-TARG DITHER 0.43 Mainly to reduce bad pixels, but half-integer rather than integer pixel spacing seems best on general principles. Main reason for dithering in this program: Since G230LB gives poor spectral resolution and S/N will not be high, even one bad pixel amounts to a major defect. LINE false false 2 90.0 STIS-ALONG-SLIT 1 false /tmp/OPVisit7873574810778505643.xml The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12785 :visit-id "01" :proposal-version -1 :trans-version "20110825" :date "14-Dec-2011 00:55:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 184448 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12785 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12785 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3034 :al-overhead-at-end 0 :internal-dur-at-end 381 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3445 :pcs-gap 0 ) true 1 0 /tmp/OPVisit2624650151952193331.xml The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12785 :visit-id "03" :proposal-version -1 :trans-version "20110825" :date "14-Dec-2011 00:55:13.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 400560 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12785 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12785 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3059 :al-overhead-at-end 0 :internal-dur-at-end 452 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3445 :pcs-gap 0 ) true 1 0