Full HST coverage of a comet-like exoplanet in transit

0 Assigned ID: 781 ----- Attempting Submission 1 (Fri Apr 10 20:31:28 GMT 2015) ----- HST Phase I Proposal 781 (GJ436b_STIS.apt) successfully submitted. Receipt: # 781-1 ----- Attempting Submission 2 (Fri Apr 10 21:53:10 GMT 2015) ----- I removed the auto-wavecals and inserted GO-wavecals during Earth occultations. 1671124127 ----- Attempting Submission 1 (Thu Jul 23 15:25:48 GMT 2015) ----- ----- Attempting Submission 2 (Sun Jul 26 02:56:59 GMT 2015) ----- No issues were encountered during past programs for this target. (Last observations were performed in June 2014.) Full HST coverage of a comet-like exoplanet in transit Exoplanets orbiting at close distances from their stars could lose some fraction of their atmospheres because of the extreme stellar irradiation. Hot rocky planets might have lost all of their atmospheres through this process, having evolved from larger progenitors with gas envelopes, possibly Neptune-mass exoplanets. The signature of this mass loss could be observed with HST/STIS at Lyman-alpha; however, there were no convincing detections of this effect for planets less massive than gas giants. New HST observations of the Neptune-mass exoplanet GJ 436b reveal a spectacular atmospheric escape. Although not strong enough to deplete the atmosphere of the planet in the lifetime of the parent star, it creates a huge exospheric cloud of atomic hydrogen eclipsing over half the stellar disk at Lyman-alpha. The exospheric cloud transit has an early ingress and numerical simulations predict it could last for almost half the 2.6-day revolution period of the planet, because of an extended comet-like tail. However, the current data do not stretch over this duration, and we propose here to use HST/STIS to cover the full transit. This will reveal the exact shape of GJ 436b exospheric cloud and allow us to discriminate between the two possible mechanism scuplting the cloud. The results could be applied to all moderately-irradiated exoplanets, in particular the planets around M dwarfs that will be detected by the TESS mission. We are going to do something similar to program GO#12965, except that we will not observe during the transit of the warm-Neptune planet as it is known in the optical. Practically, all settings will be similar to this previous program at the exception of the phase constraints on the first (ACQ) exposures of each visit. Our past observations revealed a huge comet-like cloud of hydrogen surrounding the planet. The cloud starts transiting the star at least 2h before the start of the optical transit, and the comet-like tail trails the planet for more than 3h, possibly up to 20h after the end of the optical transit. Hence, we will spread the three visits so as to sample key moments of the comet-like cloud transit. EXTRA-SOLAR PLANETS 12 false true false false AVAILABLE STAR EXTRA-SOLAR PLANETARY SYSTEM M V-IV NO This object was generated by the targetselector and retrieved from the SIMBAD database. LHS-310 J2000 J2000 STIS/FUV-MAMA Spectroscopic No No G140M 1222 1437878944006 /private/var/folders/js/1c80b2_s5dl3q50f53ds0cgh0000gn/T/OPVisit3190785522699502205.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14222 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "26-Jul-2015 04:49:03.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 907184 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14222 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14222 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 4 0 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965 1437878927711 /private/var/folders/js/1c80b2_s5dl3q50f53ds0cgh0000gn/T/OPVisit3369484720778169405.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14222 :visit-id "02" :proposal-version -1 :trans-version "20150609" :date "26-Jul-2015 04:48:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 907184 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14222 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14222 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "02" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 4 0 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965 1437878902829 /private/var/folders/js/1c80b2_s5dl3q50f53ds0cgh0000gn/T/OPVisit8674923943017715073.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14222 :visit-id "03" :proposal-version -1 :trans-version "20150609" :date "26-Jul-2015 04:48:22.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 907184 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14222 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14222 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "03" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14222 :visit-id "03" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 4 0 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965 Exact same settings as in GO#12965