Echelle spectroscopy of TCP J21040470+4631129

ATel #12936; Francois Teyssier (ARAS Group, Rouen, France)
on 13 Jul 2019; 02:43 UT
Distributed as an Instant Email Notice Transients
Credential Certification: S. N. Shore (shore@df.unipi.it)

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We report optical echelle spectroscopy (R ~ 11000, 4100-7300A) the newly reported transient TCP J21040470+4631129 (discovered on 2019 Jul.12.190 UT by Hideo Nishimura). The spectrum is consistent, obtains on 2019 Jul 12.9 UT (exposure time of 2589 sec, S/N ~ 40 hat 6100 A). The spectrum is consistent with a large amplitude outburst of a cataclysmic variable. The He I lines (e.g. 4471, 5013, 5876, 6678, 7065) all show symmetric double peaks with separation 210 km/s (HWZI ~ 540 km/s). He II 4686 shows peak separation of 310 km/s (but with there are also weak peaks coincident with the He I lines) and broader wings, HWZI ~ 700 km/s; the redshifted peak (+130 km/s) is slightly stronger and narrower. The profiles are centered at 12 km/s but the wings show asymmetric extensions. The H-alpha and H-beta profiles are asymmetric (R/V peak ~ 1.14±0.05) with separation of 160 km/s (HWZI = 600 km/s). There may be an absorption component at -30 km/s (a similar minimum is seen on the He I lines) and H-beta and H-gamma show an underlying broad absorption line that is redshifted relative to the emission component by about 150±50 km/s, based on the profile asymmetry. Additional emission includes the C III lines as a broad, featureless profile. The precursor candidate noted in the CBAT report coincides with Gaia (DR2) 2163612727665972096 with parallax 9.134+/-0.116 (g=17.77 mag)

ARAS Spectral Database