Visits 1 and 2 are being resubmitted, after HOPR 1746 re-allocated 6 of our original 8 orbits. Note that the target positions have been changed slightly, to reflect more accurately the epoch at which the 2MASS data were obtained (Simbad reports the epoch as 2000, while interrogation of the 2MASS archive reveals a different epoch for each observation). The proper motions are taken from Salim & Gould (2003) and match the equinox=2000, epoch=2000 positions when the proper motions are applied. ----- Attempting Submission 4 (Thu Jul 22 17:47:57 GMT 2010) ----- errors refer to inefficient ordering of FP-POSes, and the lack of an ACQ/SEARCH. Because the G140L/1230 setting at FP=4 can allow 0th order light on segment B, we use all FP-POS settings except this one. We are dropping an ACQ/SEARCH because of the faintness of the targets; the previous visits failed to properly acquire the targets and for these resubmitted visits we are using blind pointing. Magnetic Heating of the Outer Atmospheres of Very Low Mass Dwarfs The detections of FUV and X-ray emissions from very low mass stars and brown dwarfs have confirmed that stellar magnetic activity can survive even at these low stellar masses. The emissions are qualitatively similar to those from active stars, despite the dramatic differences between the characteristics of an ultracool (>M7) stellar atmosphere and those of earlier type cool stars. It is currently an open question how the structures and magnetic heating which exists in these very low mass stars compare with those seen in higher mass active stars. We propose to take Chandra and HST/COS spectra of two nearby active very low mass stars in order to determine the effect that these large-scale fields have on transition region and coronal structures.
We will observe two targets, both nearby late M dwarfs (LHS3003 and LHS 2065) which have shown evidence for chromospheric and coronal activity. Exposure time requests for COS G140L FUV spectra are based on existing STIS G140L spectra of VB8 and LHS 2065 which were reported in Hawley & Johns-Krull (2003). The STIS spectra were designed to obtain a detection of the C IV line flux in order to compare chromospheric-transition region scaling relations found in earlier type M stars. The measured Halpha flux for LHS 3003 is similar to that of VB8 (1.4e-14 erg/cm2/s for LHS 3003 vs. 2e-14 for VB8), and we expect that the extrapolation to C IV flux for LHS 3003 will also be similar to VB 8. The focus on the present proposal is to investigate the structures producing both transition region and coronal emission, and for this purpose we seek a deeper exposure of the FUV spectrum to explore the several diagnostics of transition region emission which exist -- N V, Si IV, and C IV. We seek a peak SNR of 10 and the C IV line, which will enable more significant detection of not just C IV but also N V and Si IV and other weak lines in this part of the spectrum. The preferred format for COS observations is TIME-TAG mode, so we will be sensitive to any flare-like variations. Because variability in both transition region and coronal plasmas is expected, we require that the Chandra and HST/COS observations overlap. 12 false 0.0 0.0 false false false false false false AVAILABLE STAR M V-IV coordinates are from epoch 2000, ICRS reference frame, taken from SIMBAD. Proper motion is taken from Cruz et al. 2007 (AJ 133, 2258): -0.509 arcseconds per year in RA, -0.814 arcsec/year in DEC, and converted to the appropriate units here. Parallax is taken from Reid & Cruz 2002 (AJ 123, 2806). GJ3877 NLTT38829 J2000 00 00 0.0000 +00 00 0.00 J2000 STAR M V-IV epoch of 2MASS coordinates are from the 2MASS point source catalog and are 06/27/1998, or 1998.487. Proper motion is taken from Salim & Gould (2003 ApJ 582, 1011): -0.497 arcseconds per year in RA, -0.827 arcsec/year in DEC. Parallax is taken from Reid & Cruz 2002 (AJ 123, 2806). GJ3877 NLTT38829 J2000 00 00 0.0000 +00 00 0.00 J2000 STAR M V-IV coordinates are from epoch 2000, ICRS reference frame, taken from SIMBAD. Proper motion is taken from Cruz et al. 2007 (AJ 133, 2258): -0.501 arcseconds per year in RA, -0.202 arcsec/year in DEC, and converted to the appropriate units here. Parallax is taken from Reid & Cruz 2002 (AJ 123, 2806). J2000 00 00 0.0000 +00 00 0.00 J2000 STAR M V-IV Epoch of 2MASS coordinates are from the 2MASS point source catalog and are 12/26/1998, or 1998.986. Proper motion is taken from Salim & Gould (2003 ApJ 582, 1011):-0.502 arcseconds per year in RA, -0.202 arcsec/year in DEC. Parallax is taken from Reid & Cruz 2002 (AJ 123, 2806). NLTT20475 J2000 00 00 0.0000 +00 00 0.00 J2000 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. 1267260061000 65.7529582603014 (Tic-Visit :proposal-id 12011 :visit-id "01" :proposal-version -1 :trans-version "20091209" :date "16-Feb-2010 12:49:32.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1043744 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12011 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12011 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2901 :al-overhead-at-end 0 :internal-dur-at-end 39 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3012 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3012 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3012 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "01" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3012 :al-overhead-at-end 0 :internal-dur-at-end 438 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) false 5 0 Target acquisition uses a strategy of FUV dispersed light in an ACQ/SEARCH. The target is both nearby (d=8.5 pc) with a high proper motion, and faint (V=18.4). No NUV fluxes exist for us to check the validity of an NUV imaging target acquisition, so we use the detected FUV spectrum from a STIS G140L exposure (reported in Hawley & Johns-Krull 2003 ApJ 588, L109). The COS ETC gives a source count rate of 0.123 cps (COS188561), and we estimate that in 289.5 seconds, there should be about 36 source photons. The target acquisition strategy uses a 1.767" step size in a 3x3 spiral pattern, with centering on the brightest step. This uses up an entire orbit. We have checked the target & field for BOP issues. The BOT returns 2 safe objects and no unknown/unsafe objects in the field. The target has been cleared using a STIS G140L 52x0.2 slit. We have also checked GALEX NUV and FUV intensity maps, and there are no bright sources within a 43" diameter macroaperture from the target. Note that Simbad lists this target as a flare star. Given its late spectral type (M9) and intrinsic faintness (V=18.5) any variability will not present a BOP concern. The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. /Users/osten/data/MULTI/vlm_uvx/OP-cache/12011-v02.xml 1269550864000 297.5383570984397 (Tic-Visit :proposal-id 12011 :visit-id "02" :proposal-version -1 :trans-version "20100505" :date "20-Jul-2010 11:48:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 347968 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12011 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12011 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2924 :al-overhead-at-end 0 :internal-dur-at-end 39 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 438 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) false 3 0 Our target acquisition strategy for this target utilizes dispersed light FUV spectra. The target is both nearby (d=6.7pc), with a large proper motion, and faint (V=17.05). There are no FUV extant FUV spectra of this object, but we expect its behavior to be similar to that of VB8, for which an FUV/STIS/G140L spectrum exists (reported in Hawley & Johns-Krull 2003 ApJ 588, L109), and we use that to estimate exposure times for the target acquisition. The COS ETC gives a SNR=5.2 for an exposure time of 293 seconds, using a dispersed light acqusition (COS.A225999). The target acquisition strategy uses a 1.767" step size in a 3x3 spiral pattern, with centering on the brightest step. This uses up an entire orbit. We have checked the target & field for BOP issues. The BOT returns 7 safe objects and no unsafe objects in the field. The target has been cleared using low dispersion large aperture IUE fluxes (LWP 31205 and SWP 55370). Note that Simbad lists this target as a flare star. We can find no published references to flaring activity on this star, and given its late spectral type (M7) and intrinsic faintness (V=17.05) any variability will not present a BOP concern. /Users/osten/data/MULTI/vlm_uvx/OP-cache/12011-v03.xml The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12011 :visit-id "03" :proposal-version -1 :trans-version "20100505" :date "20-Jul-2010 13:01:50.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 521856 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12011 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12011 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2914 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3034 :al-overhead-at-end 0 :internal-dur-at-end 438 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) false 2 0 /Users/osten/data/MULTI/vlm_uvx/OP-cache/12011-v04.xml The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12011 :visit-id "04" :proposal-version -1 :trans-version "20100505" :date "20-Jul-2010 13:01:43.0" :trans-errors '(:WARNINGS 3 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1043712 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12011 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12011 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2899 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3006 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "04" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3004 :al-overhead-at-end 0 :internal-dur-at-end 126 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12011 :visit-id "04" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3004 :al-overhead-at-end 0 :internal-dur-at-end 438 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) false 4 0