SALT spectroscopic classification of transient event Gaia22axt located within the Trumpler 14 nebula as B-star

ATel #15324; M. Gromadzki, L. Wyrzykowski (Astronomical Observatory, University of Warsaw), D. A. H. Buckley (South African Astronomical Observatory), J. Brink (University of Cape Town)
on 12 Apr 2022; 17:49 UT
Credential Certification: Mariusz Gromadzki (marg@astrouw.edu.pl)

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We report on SALT spectroscopy of transient event Gaia22axt/AT2022etv located within a Trumpler 14 nebula, discovered by Gaia Science Alerts (Hodgkin et al. 2021), https://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia22axt. A low resolution (R = 350) SALT/RSS spectra was taken on 2022-03-31, under the SALT Large Programme on transients (2021-2-LSP-001). Spectrum shows stellar continuum affected by Galactic and Interstellar extinction with absorption lines of hydrogen (Balmer series), He I and few diffuse interstellar bands. This suggests that the transient is a brightening of an early B-type stars.The transient is located just 4 arcsec away from a Young Stellar Object candidate found in Povich et al. 2011, as reported by Simbad. We suspect the brightening detected by Gaia is actually a signature of the YSO identified earlier, but the coordinates in Simbad are incorrect and the star Cl* Trumpler 14 Y 340 is the actual YSO.  Further observations of the object and its photometric and spectroscopic evolution are encouraged. The spectrum and additional details can be obtained from the IAU Transient Name Server (TNS), https://www.wis-tns.org/object/2022etv. Spectrum is not flux calibrated due to lack of observation of standard star taken with the same setup as a science target.