In 2010, COS produced a tantalising hint of a significant discovery: the magnetic field of an exoplanet. The ingress of the transiting 'hot-Jupiter' exoplanet WASP-12b apparently occurred earlier in the NUV than in the optical, and two hypotheses have been put forward as explanations. One is that this manifests dense shocked material in a magnetosheath formed in the supersonic stellar wind upstream of the planet's thus-revealed magnetic field, while the other is that this is caused in the absence of a planetary magnetic field by material overflowing the planet's Roche lobe at the L1 point. However, the previous observation, which was not designed to observe this phenomenon, is beset by scattered, sparse data and we do not yet understand the nature of the star-planet interaction. It is thus crucial that we now observe WASP-12b in a program specifically designed to unambiguously detect the early ingress, significantly improve the NUV lightcurve, and answer the question: * What is the nature of the star-planet interaction at WASP-12? No other observatory is capable of making these observations, and this proposal is highly accordant with the purpose of the Cycle 21 UV initiative. Execution in Cycle 21 is also highly desirable since the results will provide input to the LOFAR exoplanet program, which will focus on planets thought to exhibit star-planet interactions. By following a fortuitously obtained pointer, this proposal presents low risk-high impact observations, since the characterisation of star-exoplanet interactions and possibly the first detection of an exoplanetary magnetic field would be of huge scientific significance. We will obtain time-series spectroscopy of transits of WASP-12b using COS/NUV in TIMETAG mode using the G285M grating at the 267.6 nm setting. Transit duration is ~2.7 h, such that each visit requires 5 orbits at tightly-specified phases in order to cover the ingress, egress, and centre of each transit, as well as before and after. We will observe four transits as close together as possible, at slightly adjusted phases to interleave the orbits. EXTRA-SOLAR PLANETS 12 false true 0.0 0.0 false false false SUPPORTED STAR EXTRA-SOLAR PLANET G III-I J2000 J2000 B=12.1, R=11.2 COS/NUV Spectroscopic No No G285M 2676 COS/NUV Spectroscopic No No G285M 2676 COS/NUV Spectroscopic No No G285M 2676 COS/NUV Spectroscopic No No G285M 2676 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. BETWEEN is such that the planet is observable from the ground in the same epoch. This does not place strict requirements on scheduling and can be relaxed somewhat if necessary. This visit has the earliest phase for which the last orbit occurs after egress (the phase requirement is set on the ACQ/IMAGE exposure). The other visits have specified phases such that they are evenly distributed between the first and second orbits of this visit. The transit ephemerides are from Haswell et al. (2012). The FP-POS settings are such that the values in corresponding orbits in each visit are different, rather than over one visit. Therefore, the entire first visit has FP-POS=1, the second FP-POS=2, etc. and despite the warning, all four FP-POS settings are used in the program. The order in which the visits execute is not important, however they should be scheduled as close together as possible. 1381777422000 271.3504295984485 (Tic-Visit :proposal-id 13329 :visit-id "W1" :proposal-version -1 :trans-version "20130502" :date "25-Jun-2013 10:33:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 817632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W1" :obset-id "W1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W1" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W1" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W1" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W1" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W1" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3031 :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 3253 :pcs-gap 0 ) false 5 0 COS ETC (run ID COS.ta.509856) gives an exposure time of Texp = 27.2944 s to get S/N = 40 for a Castelli-Kurucz G0V star with B=12.14. Rounded up to 28 s. COS ETC (run ID COS.sp.509858) gives a Buffer-Time of 2281 s for a Castelli-Kurucz G0V star with B=12.1. BT*2/3 = 1520, rounded down to 1500 s. The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1381685538000 271.4767264750965 (Tic-Visit :proposal-id 13329 :visit-id "W2" :proposal-version -1 :trans-version "20130502" :date "25-Jun-2013 10:33:55.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 817632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W2" :obset-id "W2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W2" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W2" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W2" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W2" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W2" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3031 :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 3253 :pcs-gap 0 ) false 5 0 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1382535615000 270.2490285513747 (Tic-Visit :proposal-id 13329 :visit-id "W3" :proposal-version -1 :trans-version "20130502" :date "25-Jun-2013 10:33:58.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 817632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W3" :obset-id "W3" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W3" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W3" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W3" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W3" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W3" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3031 :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 3253 :pcs-gap 0 ) false 5 0 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1381593672000 271.6018345016606 (Tic-Visit :proposal-id 13329 :visit-id "W4" :proposal-version -1 :trans-version "20130502" :date "25-Jun-2013 10:34:00.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 817632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W4" :obset-id "W4" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W4" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W4" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W4" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W4" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3031 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W4" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3031 :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 3253 :pcs-gap 0 ) false 5 0 (Tic-Visit :proposal-id 13329 :visit-id "W5" :proposal-version -1 :trans-version "20130919" :date "29-Oct-2013 08:55:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 774112 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W5" :obset-id "W5" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W5" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2760 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W5" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W5" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W5" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W5" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 442 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) true 5 0 (Tic-Visit :proposal-id 13329 :visit-id "W6" :proposal-version -1 :trans-version "20130919" :date "29-Oct-2013 08:55:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 774112 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W6" :obset-id "W6" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W6" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2760 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W6" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W6" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W6" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W6" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 442 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) true 5 0 BETWEEN is such that the planet is observable from the ground in the same epoch. This does not place strict requirements on scheduling and can be relaxed somewhat if necessary. This visit has the earliest phase for which the last orbit occurs after egress (the phase requirement is set on the ACQ/IMAGE exposure). The other visits have specified phases such that they are evenly distributed between the first and second orbits of this visit. The transit ephemerides are from Haswell et al. (2012). The FP-POS settings are such that the values in corresponding orbits in each visit are different, rather than over one visit. Therefore, the entire first visit has FP-POS=1, the second FP-POS=2, etc. and despite the warning, all four FP-POS settings are used in the program. The order in which the visits execute is not important, however they should be scheduled as close together as possible. (Tic-Visit :proposal-id 13329 :visit-id "W7" :proposal-version -1 :trans-version "20130919" :date "29-Oct-2013 08:55:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "32" :si-bright-earth-limb-angle 20.0 :data-volume 774112 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13329 :visit-id "W7" :obset-id "W7" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13329 :visit-id "W7" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2760 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W7" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W7" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W7" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13329 :visit-id "W7" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2917 :al-overhead-at-end 0 :internal-dur-at-end 442 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3148 :pcs-gap 0 ) true 5 0 COS ETC (run ID COS.ta.509856) gives an exposure time of Texp = 27.2944 s to get S/N = 40 for a Castelli-Kurucz G0V star with B=12.14. Rounded up to 28 s. COS ETC (run ID COS.sp.509858) gives a Buffer-Time of 2281 s for a Castelli-Kurucz G0V star with B=12.1. BT*2/3 = 1520, rounded down to 1500 s.