0 Assigned ID: 1047 ----- Attempting Submission 1 (Fri Apr 10 23:33:38 GMT 2015) ----- This Phase II proposal is being submitted with 2 warnings and 2 errors, both of which arise from the unconventional GO wavecal sequence, carried out in consultation with our Contact Scientist. (GO wavecals are authorized for this program). To improve the S/N of the calibration lamp spectrum in the short-wavelength part of the FUV, an extra long (500 s) GO-wavecal has been added immediately following the regular 100s GO-wavecal after the science exposure. Both of these back-to-back wavecals are done in Earth occultation at the end of each of the 2 orbits allocated to this program. Each long (500 s) GO wavecal generates a warning ("STIS WAVE EXPOSURE TIME IS HIGH") because these wavecal exposures exceed the 300s maximum recommended for STIS. This is intentional. Each of these long GO wavecals also generates an error ("ILLEGAL STIS WAVE EXPOSURE SEQUENCE") because of the back-to-back positioning of these wavecals, which are carried out with the identical optical configuration. Only the exposure times differ. Again, this arrangement is intentional. Note that these 2 orbits *MUST* be observed contiguously as consecutive orbits because otherwise there will be a change in the stellar radial velocity due to orbital motion of this binary target. Update of Aug 25, 2015: This proposal is being resubmitted with changes requested by our Contact Scientist. The two sequences of back-to-back user-specified wavecals at the end of each orbit have been replaced with single 300s wavecals. -2110142373 ----- Attempting Submission 1 (Thu Jul 23 17:33:54 GMT 2015) ----- HST Phase II Proposal 14070 (GO-14070_Phase II.apt) successfully submitted. Receipt: # 14070-1 ----- Attempting Submission 2 (Tue Aug 25 21:04:10 GMT 2015) ----- Red supergiants (RSGs) are massive, evolved stars that are among the brightest stars in the near infrared, and often serve as useful ``standard candles'' for extragalactic and cosmological studies. But this use of RSGs is hampered by the lack of fundamental mass and luminosity calibrations tying these objects to the theoretical H-R diagram. Theoretical evolutionary models are not very useful because of mass loss due to stellar winds in the RSG stage. Mass loss in RSG stars is not well understood, and is incorporated using various parameterizations. No accurate observationally-determined RSG masses are available. More than anywhere else in the H-R diagram, there is a pressing need for accurate stellar masses of red supergiants. The determination of an accurate RSG mass is a priority. We propose to determine the mass of the K supergiant in the bright, well-studied, eclipsing binary system 31 Cygni (K4 Ib + B3 V). The orbital solution of the optically-dominant K supergiant has been accurately determined. Given this, a complete solution for both stellar masses can be found from a small number of radial velocity observations of the companion star. For 31 Cyg, archival STIS/E140H observations from 2001-02 (program GO-9109) are well-suited for this purpose. The orbital configuration of 31 Cyg in Cycle 23 is ideally separated by ~0.5 in phase from the archival observations (thereby maximizing the RV difference). We propose to obtain additional STIS/E140H observations in Cycle 23, and use these two sets of FUV observations to determine the mass of the 31 Cyg K supergiant to ~1%. These observations must be done soon, or the optimal phase window for doing so will be lost. We request a total of 2 orbits at a single visit in Cycle 23 to re-observe the eclipsing binary system 31 Cygni with the STIS E140H echelle at an orbital phase differerence of about 0.5 from that of the archival 2001 and 2002 GO-9109 STIS observations (approximately 1.5 orbits ago). This phase difference maximizes the radial velocity difference between the proposed Cycle 23 observation and the archival observations of GO-9109. Since the orbital period of 31 Cyg is long (10.36 yr), suitable phase differences will remain favourable trhoughout the nominal 2015-2016 duration of Cycle 23. These E140H echelle observations will be acquired for the spectral region from 1150 to 1400 A at a high signal-to-noise ratio of S/N ~ 50. The target is a UV-bright, non-variable, early-type star (B3 V), and therefore we will use the 0.4 dex neutral density aperture 31X0.05NDA to keep the proposed global count rates (of 90,000 to 140,000 counts/s for the various E140H exposures) below the MAMA detector global count rate limit of 200,000 counts/s. Note that the variable star designation of this target refers to the low-amplitude photometric and radial velocity variability of the K supergiant primary star, and NOT to the B-star companion. In the FUV, only the B star makes a significant contribution to the flux, and this star is not varaible. A careful examination of large aperture IUE observations of this binary out-of-eclipse (which should be reasonably photometric) confirms that FUV fluxes vary by < 5-10%, and this small variation is probably due to the limitations of the IUE flux calibration, and not to instrinsic variability of the B star. The target is a bright, point source object, and so the use of the long slit should not present any difficulty in separating the echelle orders. The proposed high S/N ~ 50 E140H spectra, in combination with the two available archival visits from program GO-9109, should suffice to determine relative velocity shifts from spectral cross-correlation to an accuracy of about 0.4 km/s. Because of the favorable orbital phase differences, these observations will sample nearly the full range of orbital velocities of this binary (= 2*K_2 ~ 46 km/s, where K_2 is the B star's radial velocity semi-amplitude). The multiplex advantage of using three pairs of correlations (from the three observations) should further reduce the error on 2*K_2 to about 0.2 km/s. Therefore, we expect to determine K_2 to ~0.1 km/s. The primary orbit of the K4 Ib supergiant is very well determined: K_1 is known to an accuracy of 0.04 km/s. Therefore, an accurate determination of K_2 of this eclipsing binary will yield an accurate solution of the binary. We expect the proposed STIS/E140H observation to determine the masses of the K supergiant accurate to ~1%. We have received approval to use the "AVAILABLE" modes option in APT, specifically the use of WAVECAL=NO and of user-specified GO wavecals (TARGET=WAVE) for each of the science exposures of the (single) Visit 1. The science objective requires accurate wavelength calibrations, because the orbital solution depends directly upon the accuracy to which the B-star secondary's radial velocity semi-amplitude K_2 can be determined from the proposed STIS/E140H echelle observations. The value of K_2 will be found by cross-correlation of the observed FUV spectrum with that observed by the PI's previous program GO-9109, when the B star was on the opposite side of its orbit. Tom Ayres (University of Colorado, Boulder) has offered the investigators the use of his ASTRAL-II software to carry out a custom reduction and wavelength calibration of these observations. He recommended that (1) we use the 0.2X0.09 aperture for the lamp (wavecal) exposures to improve wavelength accuracy, and (2) we use longer wavecal (100 s) exposures to increase the S/N of the lamp spectrum, which is weak shortward of 1300 A. The region from 1150-1300 A is the region of focus for the science objectives of the program because this is the spectral region where the B star is most heavily line-blanketed (as needed for accurate radial velocity measurements). We use four CENWAVE configurations of E140H: 1234, 1271, 1307, and 1343 to improve the line spread function by dithering as provided by the substantial overlap of spectral coverage from these exposures. We have also broken all science exposures into subexposures of maximum length of ~300 s in order to minimize spacecraft Doppler smearing, and provide additional wavelength dithering of the observations. The science exposures have been arranged so that the shortest wavelength observations (CENWAVE=1271 and 1234) occur as the last science exposures of orbits 1 and 2 respectively, immediately prior to Earth occultation. The calibration lamp is very weak at these short wavelengths, and in order to improve the S/N of the lamp spectrum obtained in this short-wavelength region of the FUV, we have scheduled *two* back-to-back GO-wavecals in Earth occultation immediately following each of the E140H/1271 and 1234 science exposures, in consultation with our Contact Scientist, Charles Proffitt. The first wavecal is of length 100s, whereas the second is a longer 500 s exposure. Both are taken with the identical optical configuration. The second of each of these GO-wavecals produces one warning (of high WAVECAL expsoure time > 300 s) and one error (of illegal STIS wave exposure sequence). However, we have been assured by our CS that these back-to-back wavecals are technically feasible, even though they are flagged as errors in APT. We request that these wavecal observations be carried out as submitted. Update of Aug 25, 2015: Charles Proffitt requested that the double back-to-back wavecals at the end of each orbit be replaced by single user wavecal of length 300s, so that it will not generate errors in APT and can be put into the long range plan. This has been done in the latest version of this Phase II Proposal. COOL STARS 12 false true false false false false AVAILABLE STAR B3-B5 V-IV COMPOSITE SPECTRAL TYPE This object was generated by the targetselector and retrieved from the SIMBAD database. HD192577 31-CYG J2000 J2000 F_lam(1270 A)= 1.7e-10 ergs/cm2/s/A (not variable, except during eclipse every 10.3 yrs -- NOT variable in Cycle 23) STIS/FUV-MAMA Spectroscopic No No E140H 1234 STIS/FUV-MAMA Spectroscopic No No E140H 1271 STIS/FUV-MAMA Spectroscopic No No E140H 1307 STIS/FUV-MAMA Spectroscopic No No E140H 1343 1467233396285 /private/var/folders/bl/s7q0tqnn5gbcbyvcfnrhj2rh0004nc/T/OPVisit1566774230550402927.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14070 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "29-Jun-2016 16:49:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1044816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14070 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14070 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3019 :al-overhead-at-end 411 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14070 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3127 :al-overhead-at-end 411 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) true 2 0