0 Assigned ID: 1974 ----- Attempting Submission 1 (Fri Mar 01 23:58:15 GMT 2013) ----- HST Phase I Proposal 1974 (NGC1851_FUV1.apt) successfully submitted. I have used the image J9L910010 from proposal 10775 to determine the positions of the red giant offset stars and the position of our target FUV1. I have choosen to use two offset stars. The second one is closer to our target star. I choose to peak up on both offset stars before moving to the target star. The location of the target star is very crowded and the accuracy of the pointing is extremely important. 970885825 ----- Attempting Submission 1 (Thu Jun 27 21:38:03 GMT 2013) ----- We have recently discovered an 18-minute period in the ultraviolet of a star in the globular cluster NGC 1851. In the redder optical bands, this star is red and bright, while it shows a clear UV excess relative to other stars at similar positions in the HR diagram. The system is most likely a symbiotic binary, composed of a cool evolved star and a white dwarf, with an 18 minute spin period, accreting the cool star's wind. The binary would be the first such object ever found in a globular cluster, and only the third in the Galaxy where the white dwarf spin period is measured. The only viable alternatives are that the two components are a chance superposition -- something with a nontrivial chance of happening in a globular cluster core. In such a case, the 18 minute period would most likely be the spin period of a magnetic white dwarf in an intermediate polar cataclysmic variable (this would be the first confirmed magnetic CV in a globular cluster), or the orbital period of a double-degenerate AM CVn binary. Each of these three possibilities show unique (and very different) emission line spectra in the blue wavelength range. Two orbits of HST with STIS/G430L will produce a spectrum of sufficient signal-to-noise to distinguish between these 3 scenarios. The result will be an important constraint on N-body models of globular clusters. The cluster center where our target star is located is extremely crowded and would make acquiring and peaking up extremely difficult. In order to alleviate this difficulty we will acquire and peak up on a red giant located to the south and east of our target star out side the most crowded region. We will then move to a second red giant which is closer to our target (about half the distance) and peak up on this second red giant before moving to our target star. Our target star is located right in the cluster core. Once we have moved to our target star we will expose using the grating G430L for the rest of the time. The positions for the two red giants and our target star have been determined using the reference image J9L910010 from proposal 10775 (PI: Sarajedini). RESOLVED STELLAR POPULATIONS Default false false false false false SUPPORTED STAR M V-IV This is a red giant located to the south and east of our target. This is using the data from proposal 10775 ACS/WFC imaging (J9L910010). J2000 STAR M V-IV This is a second red giant star located closer to the target star. It is slightly to the south and west of our target. The position is determined from the proposal 10775 ACS/WFC imaging (J9L910010). J2000 STAR ACCRETION DISK COMPOSITE SPECTRAL TYPE INTERACTING BINARY SYMBIOTIC STAR This is our target star. It is located slightly north and west of the red giant. It is located right in the center of the cluster and is thus extremely hard to peak up on. The position is determined from the proposal 10775 ACS/WFC imaging (J9L910010). J2000 J2000 STIS/CCD Spectroscopic No No G430L 4300 1372369071606 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13394 :visit-id "01" :proposal-version -1 :trans-version "20130502" :date "27-Jun-2013 17:37:50.0" :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 294960 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13394 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13394 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2988 :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 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13394 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3079 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) false 2 0 This is the first red giant located south and slightly to the east of our target. We will acquire and peak up on this star. It's magnitude is about 13.0 and is one of the brightest red giants in this part of the cluster. The cluster core, where our target is, is too crowded and acquisition is not possible. This is the first red giant located south and slightly to the east of our target. We will acquire and peak up on this star. It's magnitude is about 13.0 and is one of the brightest red giants in this part of the cluster. The cluster core, where our target is, is too crowded and acquisition is not possible. This is a second red giant which is closer to our target. It is located to the south and slightly to the west of our target. We will preform a peak up on this red giant and then proceed to our target star. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. Note: this exposure has been adjusted to fill the orbit. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We adjusted the exposure time to 660 seconds to fill the orbit better. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We adjusted the exposure time to 660 seconds to fill the orbit better. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We adjusted the exposure time to 660 seconds to fill the orbit better. We wish to obtain a series of spectra with a signal-to-noise of about 30 in the continuum within each spectrum. This works out to about a 600 seconds. We will continue to take spectra of this length for the rest of the visit. We adjusted the exposure time to 660 seconds to fill the orbit better.