Classification certificate for object 2019udc
TNS Classification Report No. 5448 [ 2019TNSCR2287....1S ]

Date Received (UTC): 2019-11-05 07:17:25
Sender: Cesar Rojas-Bravo
Group: UCSC

M. R. Siebert, G. Dimitriadis, C. D. Kilpatrick, R. J. Foley, R. Nunez, K. McKinnon and P. Guhathakurta (UCSC) report/s a classification of object: AT 2019udc

Type: LBV
Redshift: 0.006

Remarks: Red spectrum (black body temperature ~ 4,500 K, assuming no host extinction) with a distinctive narrow H-alpha emission feature (FWHM ~ 1300 km/s), red-shifted at 260 km/s relative to the host (NGC 718, with spectroscopic redshift z = 0.005781). The (observed) absolute magnitude of the transient is M_r = -13.3, and dereddening by an appropriate amount to match the Na D absorption strength (EW ~ 6 Angstroms), we estimate a temperature of 15,700 K and an absolute magnitude of ~ -16. We consider these properties most similar to a reddened LBV outburst, however it is also consistent with a luminous red nova. We thank the Lick Observatory staff for helping with these target-of-opportunity observations. ATel: 13263

The following Classification spectrum was provided:

Obsdate: 2019-11-04 06:54:08
Instrument: KAST
Telescope: 3m Lick Shane Reflector

Details of the object and its spectra can be viewed here: https://wis-tns.weizmann.ac.il/object/2019udc