Thelight curve of V1280 Scorpii, plotted fromAAVSO data and (inset) the Solar Mass Ejection Imager light curve covering the time around peak brightness.[4]
V1280 Scorpii (orNova Scorpii 2007 Number 1) is the first of twonovae that occurred in the constellationScorpius during February 2007 (the second nova was the fainter V1281 Scorpii, which was discovered on 19 February 2007). Announced by theIAU in Electronic Telegram No. 835 and Circular No. 8803, the nova'smagnitude was 9.6 when it was discovered on CCD images taken at 20:42 UT on 4 February 2007 by Yuji Nakamura ofKameyama, Mie, Japan. It was independently discovered on the same night at 20:30 UT by Yukio Sakurai ofMito, Ibaraki, Japan. It peaked at magnitude 3.79 on February 17, making it easily visible to thenaked eye.[5][6][7] V1280 Scorpii is two degrees south ofM62.
The location of V1280 Scorpii (circled in red)
The early period after V1280 Scorpii's eruption was observed in great detail by theSolar Mass Ejection Imager (SMEI) instrument on theCoriolis satellite. This satellite obtained a brightness value for the nova every 102 minutes. The rise to peak brightness was exceptionally slow.[8] The SMEI light curve shows three well defined maxima for the nova, occurring around 03:00 UT on 16 February, 08:30 UT on 17 February and 05:00 UT on 19 February 2007.[4] The nova declined slowly from peak brightness until the end of February 2007, at which time it began fading rapidly as dust formed in the ejected material. At the same time dust formation was causing the visual light curve to plummet, the infrared brightness increased.[9] The formation of V1280 Scorpii's dusty structure was observed in the near (K-band) and mid (N band) infrared by theVLT interferometer, and the interferometer was able to measure the expansion of the dust shell. These were the first such observations for any nova.[8]On day 100, another brightening was observed, which corresponded to a second mass loss event. The expanding dust shell around the nova has an estimated velocity of 350 km/s.[10] The mass of the nova's white dwarf has been estimated to be 0.6M☉, based on the SMEI light curve.[4]
The morphology of V1280 Scorpii'snova remnant is complex, but overallbipolar in shape; on either sides of the nova are outflows emittingforbidden lines ofoxygen (O III) andnitrogen (N II). Surrounding the center is an equatorial torus of dust, which variably blocks light.[11]
