Optical and near-IR spectroscopy of nova Oph 2017 (TCP J17394608-2457555)
ATel #10420; Ashish Raj, M. Pavana, G. C. Anupama, Anirban Bhowmick, Rahul Dar and Pramod Kumar S. (Indian Institute of Astrophysics)
on 24 May 2017; 11:52 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Ashish Raj (firstname.lastname@example.org)
Subjects: Infra-Red, Optical, Nova
We report optical and near-IR spectroscopic observations of the nova Oph 2017 (ATel #10366, #10367, #10369). The optical spectrum on May 11, 2017 was obtained using the HFOSC instrument mounted on the 2m Himalayan Chandra Telescope (HCT) of the Indian Astronomical Observatory, Hanle, India, in the 380-800nm wavelength range. The spectrum shows hydrogen Balmer lines, several Fe II lines, O I lines at 7773, 8227 and 8446 and Ca II triplet lines. The FWHM velocity of the H-alpha line was measured to be ~1280 km/s.
The HK band spectra on May 17, 2017 were obtained using the TIRSPEC instrument mounted on the HCT, in the cross dispersion mode. The spectra show Brackett lines, Na I line at 2.2056 micron and weak CO first overtone bands at 2.2935 and 2.3227 micron. The FWHM velocity of the Br-gamma line was measured to be ~1370 km/s.
The CO bands in our observations on May 17, 2017 have weakened. Comparing with other CO emitting novae such as V2274 Cyg, V705 Cas and V842 Cen, their ejecta velocity and the time of dust formation after the last CO detection, it is likely to see dust formation in next 15-20 days in nova Oph 2017. Observations with the HCT are continuing.