The first spectrally resolved Ha measurement of an accreting planet

Some last minor comments 176720829 Your proposal could not be saved. Submission aborted. Assigned ID: 267 ----- Attempting Submission 1 (Thu Apr 07 19:39:52 GMT 2016) ----- HST Phase I Proposal 267 (LkCa15.apt) successfully submitted. Receipt: # 267-1 ----- Attempting Submission 2 (Thu Apr 07 19:55:48 GMT 2016) ----- HST Phase I Proposal 267 (LkCa15.apt) successfully submitted. Receipt: # 267-2 ----- Attempting Submission 3 (Fri Apr 08 07:57:00 GMT 2016) ----- HST Phase I Proposal 267 (LkCa15.apt) successfully submitted. Receipt: # 267-3 ----- Attempting Submission 4 (Fri Apr 08 08:13:07 GMT 2016) ----- Coordinates updated to 2016.8 (proper motion wrt 2000 amounts to 0.3 arcsec). -1785420226 ----- Attempting Submission 1 (Wed Jul 20 20:56:33 GMT 2016) ----- HST Phase II Proposal 14698 (LkCa15_phase2_final.apt) successfully submitted. Receipt: # 14698-1 ----- Attempting Submission 2 (Thu Jul 21 16:36:29 GMT 2016) ----- The first spectrally resolved Ha measurement of an accreting planet LkCa 15 b was recently detected in Halpha using AO enhanced imaging and we propose to follow-up on this detection with HST STIS observations to provide, for the first time, a velocity resolved profile of planetary Ha emission. The velocity shift of the Ha emission is related to the planetary accretion mode, magnetospheric or boundary layer accretion. If a velocity shift is found that is close to the free-fall velocity, this would point to magnetospheric accretion, and thus, would provide evidence of early planetary magnetic fields. The goal of the observations is to obtain extremly high S/N data on the Halpha line with the slit aligned along the line connecting the star and the planet (separated from the star by about 0,1 arcsec). We take the P.A. of Sallum et al. (2015) extrapolated to the approx. date of the observations (P.A. about 254 deg, East of North). To exclude systematics, we repeat the observations with HST rotated by 180 deg. The target is moderately variable so that we have to budget for this when calculating exposure times to safely avoid saturation. Exposure times are calculated from an ESO VLT Xshooter spectrum of the source scaled to match the photometry of Grankin et al. (2007). Running the ETC using this spectrum implies that we have to use multiple short exposures to avoid saturation, which is also the rationale for using CCDGAIN=4. To reduce the overhead, in particular the readout time, we use a subarray mode. We readout 64 pixel (or 3.2 arcsec) around the center of the spectral trace. This ensures that the relevant part of the detector is read in all exposures, i.e., the detector region that can be used for background estimates is covered in all exposures despite dithering. Dithering along the slit is implemented to avoid detector artifacts falling in the region of the Halpha line. We specifically implement a 5-point dither with steps of 4.2 pixel (or 0.213 arcsec per step and a total shift of 0.852 arcsec). Thereby, we shift the spectral trace by several PSF-widths to avoid potential detector artifacts and expect that the spatial centroid of the spectral trace falls onto different locations with respect to the pixel center. Target ACQ and ACQ/PEAK: Using the Xshooter spectrum suggests that an exposure time of 0.2 s with the F28x50LP filter provides a similar margin against over- and underexposure. This also applies to the ACQ/PEAK exposure. Extrasolar Planets and Planet Formation 12 false false false false false false SUPPORTED STAR PRE-MAIN SEQUENCE STAR T TAURI STAR Coordinates are for 2016.8. Proper motion within one year is on the 10 mas level and can, therefore, be neglected here. The object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STIS/CCD Spectroscopic No No G750M 6581 STIS/CCD Spectroscopic No No G750M 6581 POS-TARG DITHER 0.213 This is to shift the spectrum in the spatial direction along the slit by half-pixel offsets. LINE false true 5 90.0 STIS-ALONG-SLIT 1

false

1469118810597 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /home/majestix/hdd/HST/OP-cache/LkCa15_phase2_final-v01.xml (Tic-Visit :proposal-id 14698 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 18:33:28.0" :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 84480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14698 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14698 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2783 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3118 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14698 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2896 :al-overhead-at-end 75 :internal-dur-at-end 391 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3118 :pcs-gap 0 ) true 2 0 Exposure times calculated from the Xshooter spectrum (date obs: 2011-12-02): ETC gives: Exptime for S/N=40: 0.0367 seconds Time to Saturation (for a single exposure) = 1.86 seconds Exposure times calculated for a Pickles K5 star and V=12: ETC gives: Exptime for S/N=40: 0.0339 seconds Time to Saturation (for a single exposure) = 1.61 seconds This suggests that an exposure time of 0.25 s provides a factor of seven margin against under-exposing and a similar margin against saturation. See Exposure 1 See also STIS.sp.827044 for a run with a brighter input spectrum. In fact, we estimate that the Ha line, which we are interested in, can be even a factor of two brighter. Therefore, the current exposure times provide a factor of two margin against saturation. 1469118816266 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /home/majestix/hdd/HST/OP-cache/LkCa15_phase2_final-v02.xml (Tic-Visit :proposal-id 14698 :visit-id "02" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 18:33:34.0" :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 66080 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14698 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14698 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2723 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3060 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14698 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2834 :al-overhead-at-end 0 :internal-dur-at-end 371 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3060 :pcs-gap 0 ) true 2 0 Exposure times calculated from the Xshooter spectrum (date obs: 2011-12-02): ETC gives: Exptime for S/N=40: 0.0367 seconds Time to Saturation (for a single exposure) = 1.86 seconds Exposure times calculated for a Pickles K5 star and V=12: ETC gives: Exptime for S/N=40: 0.0339 seconds Time to Saturation (for a single exposure) = 1.61 seconds This suggests that an exposure time of 0.25 s provides a factor of seven margin against under-exposing and a similar margin against saturation. See Exposure 1 See also STIS.sp.827044 for a run with a brighter input spectrum. In fact, we estimate that the Ha line, which we are interested in, can be even a factor of two brighter. Therefore, the current exposure times provide a factor of two margin against saturation.