LCO observations of V1047 Cen
ATel #12893; F. Di Mille, E. Congiu, N. Morrell, K. Boutsia (LCO)
on 27 Jun 2019; 04:16 UT
Credential Certification: Francesco Di Mille (fdimille@lco.cl)
We report observations of the rebrightening of V1047 Cen (Atel #12876) obtained with the Magellan Clay telescope at Las Campanas Observatory.
A fully calibrated spectrum covering the wavelength range 4100-10200 Angstrom (R~700) taken with the LDSS3 spectrograph (VPH-all, 1 arcsec slit, 960s) on June 19.167 UT, shows strong emission lines on a red continuum. The strongest emission lines are Halpha and [O III]5007 with Halpha having a flux slightly larger than [O III]5007.
We confirm most of the emission lines reported by Aydi et al. (ATel #12885). The broader wavelength range of our low-resolution spectrum allowed to detect both HeII 4686 and HeII 10124 which were used to determine a reddening of E(B-V)=1.1 following Williams et al. 1994. A similar value was recovered using the ratio Hbeta/HI(10049), although we note that the Hbeta/HI(10049) over HeII(4686)/HeII(10124) ratio is about 2.2, lower than the theoretical value of 4 (Williams et al. 1994).
We also observed V1047 Cen with the Echelle Mike Spectrograph on June 19.006 UT, for a total exposure time of 3600 s with the 1 arcsec slit. The spectrum, which covers the range 4200-8900 Angstrom with a resolution R~27000, reveals the complex profile of the emission lines. [O III] in particular has at least 15 resolved components with velocity in the range -400 +400 km/s confirming a FWZI of about 1000 km/s as found by Aydi et al. (ATel #12885). HI (4861) and HI (4340) show a weak P-Cyg profile with a velocity of about -1200 km/s.
We also detected diffuse interstellar bands (DIBs) at 5780,5797,6196,6613 Angstrom. By using the relation between the equivalent width of the 5780 DIB and extinction found by Phillips et al. 2013, we estimate a reddening of E(B-V)=1, which is compatible with the values obtained with the emission lines in the flux calibrated low-resolution spectrum but lower than what reported by Aydi et al. (ATel #12885).
