SALT spectroscopic classification of ASASSN-19mo as a classical nova

ATel #12795; E. Aydi (MSU), D. A. H. Buckley (SAAO), L. Chomiuk, A. Kawash, K. Sokolovsky, J. Strader (MSU), K. Z. Stanek, C. S. Kochanek, J. Shields, C. M. Basinger (OSU), B. J. Shappee (Univ. of Hawaii)
on 22 May 2019; 19:16 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Elias Aydi (eaydi@saao.ac.za)

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We report on high-resolution optical spectroscopy of the transient ASASSN-19mo, which was discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN: Shappee et al. 2014; Kochanek et al. 2017) on 2019-05-13.34UT.

On 2019-05-22.12UT, we obtained a 900 s spectrum using the High Resolution Spectrograph (HRS; Crause et al. 2014, Proc. SPIE, 91476) mounted on the 11m Southern African Large Telescope under 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 is dominated by P Cygni profiles of the Balmer, Fe II, O I, and Na I lines. The emission lines are weak, as is typical for classical novae in the optically thick phase near maximum light. Halpha shows the strongest emission line, with a FWZI of around 820 +\- 20 km/s. The Hbeta emission line is weaker and narrower with a FWZI around 490 +\- 20 km/s. The absorption features of the Halpha and Hbeta P Cygni profiles both lie at a heliocentric velocity of around -470 +\- 10 km/s relative to their rest wavelengths. The spectrum also has a large number of unidentified absorption features, possibly THEA features (see, e.g., Williams et al. 2008, ApJ 685, 451). The Na D interstellar absorptions show two distinct features, in both D1 and D2, at -130 km/s and -30 km/s. The large EW (~ 1.8 - 2.4 A) of the D1 and D2 absorptions indicate high reddening towards the nova, consistent with the Galactic reddening maps (Schlafly & Finkbeiner 2011, ApJ, 737, 103).

The latest ASAS-SN light curve shows that the object is near maximum light. Follow up observations are strongly encouraged in all bands.

 
Line identifications: 
H I : 4102, 4340, 4861, and 6563 A. 
O I: 7002, 7773, 8446 A. 
Na I: 5892 and 66159 A. 
Ca II: 8498, 8542, and 8662 A. 
Si II: 6347 and 6371 A. 
Mg II: 7896 A. 
Fe II (38): 4554 A. 
Fe II (41): 5276 A. 
Fe II (42): 4924, 5018, and 5169 A.  
Fe II (46): 5991 and 6084 A.  
Fe II (49): 5235 and 5317 A.  
Fe II (73): 7462 and 7712 A. 
Fe II (74): 6148, 6248, 6417, and 6456 A.