SALT spectroscopy of the Galactic transient TCP J17234205-3103072
ATel #14015; E. Aydi (MSU), D. A. H. Buckley (SAAO), J. Mikolajewska (NCAC), M. Orio (UoW/INAF), L. Chomiuk, A. Kawash, K. V. Sokolovsky and J. Strader (MSU)
on 15 Sep 2020; 22:14 UT
Credential Certification: Elias Aydi (eaydi@saao.ac.za)
Subjects: Optical, Binary, Cataclysmic Variable, Nova, Star, Transient, Variables
We report on high-resolution optical spectroscopy of the transient TCP J17234205-3103072, which was discovered by T. Kojima (Tsumagoi, Gunma-ken, Japan) on 2020-09-08.42 UT.
On 2020-09-14.80 we obtained a 1200 s spectrum using the High Resolution Spectrograph (HRS; Crause et al. 2014, Proc. SPIE, 91476) mounted on the 11m Southern African Large Telescope as part of the SALT Large Science Program on Transients. The observations were taken in the LR mode of HRS which covers the spectral range of 3800-8900 A at a resolution of R=14000. The data were reduced with the SALT HRS MIDAS pipeline (Kniazev et al. 2016, MNRAS 459, 3068).
The spectrum shows emission lines of Balmer, O I, He I, Fe II, and He II. The FWHMs of these lines range between 400 and 600 km/s. Halpha shows a broad emission base characterized by a FWZI of around 9000 km/s with the narrower line superimposed on it. The unusual profile of Halpha is also visible in the spectra obtained by M. Fujii (vsnet-alert 24684).
The spectrum resembles that of symbiotic novae however we find no explanation for the additional broad emission component in Halpha. We do not see any features from a red giant star in the red/near IR part of the spectrum nor any forbidden lines. Based on the low velocities we speculate that the transient could alternatively be a red nova.
Follow up observations in all bands are encouraged.
