0 Assigned ID: 1082 ----- Attempting Submission 1 (Fri Apr 11 23:42:29 GMT 2014) ----- 0 ----- Attempting Submission 1 (Tue Jul 08 21:13:56 GMT 2014) ----- The Origin of Intermediate-Luminosity Red Transients Intermediate-luminosity red transients (ILRTs) are a new class of optical transients. They have maximum luminosities between novae and SNe, and outbursts lasting several months, becoming cool, dusty, and extremely red as the eruptions proceed. A prototype is V838 Mon, which illuminated a spectacular light echo. Their outbursts may be due to catastrophic stellar collisions and mergers. This is demonstrably true for V1309 Sco, which was a contact binary before its eruption and is now a single star. However, it is not yet clear whether all ILRTs are due to mergers. I propose WFC3 imaging of 3 ILRTs: (1) V4332 Sgr, which erupted in the Galactic bulge in 1994, is now a 19th-mag, very red remnant. Based on a high degree of linear polarization in ground-based measurements, it has been proposed that it is surrounded and obscured by a dusty, edge-on envelope, ejected during a stellar merger. If so, V4332 Sgr ought to display a dark lane at HST imaging resolution. (2) M31 RV is an ILRT that occurred in the bulge of M31 in 1988. HST images of the site taken between 1999 and 2010 failed to reveal a credible remnant of this event. However, models of expanding dusty envelopes predict that eventually, as the optical depth diminishes, the remnant should brighten. The passage of 5 years since the last HST observation of the field justifies another attempt to identify the putative merged binary. (3) CK Vul, the bright "nova" of 1670, is a candidate ILRT because of its red color and an outburst light curve resembling that of V838 Mon. A faint bipolar nebula lies at the site of CK Vul, but no credible remnant star has been found in ground-based images. HST resolution may reveal it. I will use WFC3 UVIS and IR channels to image the sites of three intermediate-luminosity transients: V4332 Sgr: exposures in B (F438W), V (F606W), and I (F814W) in order to search for a resolved compact nebula and a possible dark band across it. M31 RV: repeat imaging last done in 2009-2010 in F814W and F160W, to search for any faint red sources that may have brightened since the observations ~5 years ago. CK Vul: deep images in F300X (to search for possible faint, hot star responsible for exciting the faint emission nebula at the outburst site), and in F606W and F160W (to search for a possible faint red remnant star). Standard dithering patterns will be used for all of the imaging. COOL STARS Default false true false false false AVAILABLE STAR CIRCUMSTELLAR MATTER DUST LANE EJECTA M III-I This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 EXT-STAR CIRCUMSTELLAR MATTER EJECTA M III-I This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STAR CIRCUMSTELLAR MATTER CLASSICAL NOVA EJECTA EMISSION LINE NEBULA INTERACTING BINARY This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F814W WFC3/IR Imaging No No F160W WFC3/UVIS Imaging No No F300X WFC3/UVIS Imaging No No F606W WFC3/IR Imaging No No F160W WFC3/UVIS Imaging No No F656N POS-TARG DITHER 0.135 LINE false true 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.605 LINE false false 3 41.788 WFC3-IR-DITHER-LINE-3PT 2 false POS-TARG DITHER 0.572 LINE 0.365 false true 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 3 false /tmp/OPVisit3547636356068581506.xml The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. UVIS imaging of V4332 Sgr. ORIENT requirements are added to avoid charge bleed and diffraction spikes from a bright neighboring star 10".5 away from target. (Tic-Visit :proposal-id 13851 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "08-Jul-2014 17:04:32.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 178256 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13851 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13851 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2898 :al-overhead-at-end 83 :internal-dur-at-end 231 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3232 :pcs-gap 0 ) true 1 0 /user/bond/klingsor1/hstcycle22/ckvul/OP-cache/13851-v02.xml The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13851 :visit-id "02" :proposal-version -1 :trans-version "20140605" :date "08-Jul-2014 15:14:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 67744 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13851 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13851 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2983 :al-overhead-at-end 0 :internal-dur-at-end 156 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3316 :pcs-gap 0 ) true 1 0 /user/bond/klingsor1/hstcycle22/ckvul/OP-cache/13851-v03.xml The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13851 :visit-id "03" :proposal-version -1 :trans-version "20140605" :date "08-Jul-2014 16:11:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 375712 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13851 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13851 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 172 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13851 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3019 :al-overhead-at-end 0 :internal-dur-at-end 492 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) true 2 0