Spectroscopic classification and BVRI photometry of TCP J05210763+2338194 as a FeII-type nova

ATel #17950; U. Munari (INAF Padova), P. Valisa and S. Dallaporta (ANS Collaboration)
on 8 Aug 2026; 08:28 UT
Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it)

Tweet

The transient TCP J05210763+2338194 was discovered on 2026 Aug 06.4109 UT at unfiltered 11.2 mag (calibrated against V magnitudes of Tycho-2 stars in the field) by the NMW-TexasTech survey. According to ATel #17947, on Aug 7.0451 UT it has been measured at unfiltered 10.5 mag (calibrated against G magnitudes of Gaia stars in the field). No multiband, calibrated photometry or classification spectroscopy is available

We have recorded BVRI photometry of TCP J05210763+2338194 on Aug 8.109 UT with ANS Collaboration telescope ID 0310, which, transformed via APASS DR8 to the Landolt (2009) standard system, yields:

UT	V	B-V	V-R	V-I
2026 Aug 8.109	10.688	+0.787	+0.622	+1.203

A low-resolution spectrum (3820-9200 Ang, 1.42 Ang/pix) of TCP J05210763+2338194 has been recorded through passing clouds on Aug 8.125 UT with the Varese 0.84m telescope, equipped with a Multi-Mode Spectrograph operated in single dispersion mode. The spectrum is dominated by Balmer, OI and FeII emission lines superimposed on a smooth continuum with weak interstellar absorptions.

Balmer lines are characterized by a FWHM=800 km/s emission component and a sharper P-Cyg absorption, blue-shifted by 500 km/s. OI 7772 and 8446 lines are both present in emission, at equal intensity. For OI 7772 the emission component has FWHM=670 km/s and it is flanked by a deep P-Cyg absorption blue-shifted by 440 km/s. FeII emission lines are dominated by multiplet N.42 with a FWHM=670 km/s and no P-Cyg absorption component. HeI 5876 is also probably present in weak emission, flanked by an apparent low-velocity P-Cyg absorption, which is more likely due to superimposed and multi-component NaI of stellar and interstellar origin.

The spectrum fits well a standard FeII-type nova, probably caught in the early post-maximum phase. The modest Halpha/Hbeta ratio (6.4), the weakness of interstellar features, and the modest (B-V) color suggest a low reddening affecting this nova located at 7 deg Galactic latitude in the anti-center direction.