Spectroscopic Observations of recurrent nova T CrB: H-alpha, H-beta, and He II emission lines
ATel #17110; C. Moraitis, I. Srijumnong, S. Eikenberry, T. Thomas, A. Akers , (University of Central Florida), M. C. Bentz (Georgia State University)
on 25 Mar 2025; 18:45 UT
Credential Certification: Christina Moraitis (christina.moraitis@ucf.edu)
Subjects: Optical, Binary, Cataclysmic Variable
We present three spectroscopic observations (3-March, 7-March, 19-March 2025) of recurrent nova, T Corona Borealis, with the OPASpec spectrograph (Moraitis et al. 2024) on the Robinson Observatory 0.5m telescope in Orlando, FL, U.S.A. We measure equivalent widths (EW), the full width at zero intensity (FWZI), and the full width at half max (FWHM) for the H-alpha and H-beta emission lines. We also measure EWs of the He II emission line at 4685.7A.
Table 1: H-Alpha Line Analysis
Date (EST) | FWHM (km/s) | FWZI (km/s) | E.W. (A) | Line Centroid (A)
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2025-03-03T00:30 | 230 +/- 50 | 560 +/- 120 | -10.2 +/- 0.7 | 6561.5 +/- 0.2
2025-03-07T00:30 | 230 +/- 40 | 560 +/- 90 | -5.5 +/- 0.4 | 6561.6 +/- 0.3
2025-03-19T05:00 | 220 +/- 40 | 560 +/- 90 | -13.1 +/- 1.0 | 6562.0 +/- 0.3
Table 2: H-Beta Line Analysis
Date (EST) | FWHM (km/s) | FWZI (km/s) | E.W. (A) |Line Centroid (A)
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2025-03-03T00:30 | 220 +/- 40 | 600 +/- 100 | -5.5 +/- 0.4 | 4860.4 +/- 0.1
2025-03-07T00:30 | 230 +/- 40 | 460 +/- 100 | -3.1 +/- 0.2 | 4860.2 +/- 0.2
2025-03-19T05:00 | 210 +/- 40 | 470 +/- 90 | -5.8 +/- 0.6 | 4860.4 +/- 0.2
Table 3: He II Line Analysis
Date (EST) | E.W. (A)
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2025-03-03T00:30 | -1.1 +/- 0.1
2025-03-07T00:30 | -0.7 +/- 0.05
2025-03-19T05:00 | -1.6 +/- 0.2
Linewidths of both H-alpha and H-beta remain stable within our uncertainties. We observe a varied trend in EWs. EWs of H-alpha, H-beta, and He II emission features decreased on 7-March (as compared to 3-March), H-alpha increased on 9-March (as stated by Hristova et al. in ATel #17075) then lowered again on 19-March. He II emission indicates evidence of hot, high-energy ionization radiation from the white dwarf. Continued increase of He II emission could indicate nova eruption in the near future. Observations contain 18 x 300s exposure for 3-March and 10 x 300s exposures for 7-March and 19-March. We will continue to spectroscopically monitor this system.
References:
Christina D. Moraitis and Stephen S. Eikenberry "OPASpec: a double spectrograph for the Original PolyOculus Array", Proc. SPIE 13096, Ground-based and Airborne Instrumentation for Astronomy X, 1309635 (18 July 2024); https://doi.org/10.1117/12.3018947
PDF of Plots and Tables
