Transition of the H-alpha line from absorption to a double-peaked emission in the Be star HD 224544

ATel #6362; V. Desnoux (for the ARAS group)
on 2 Aug 2014; 16:46 UT
Credential Certification: S. N. Shore (shore@df.unipi.it)

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We report the observation of an emission event in H-alpha for the Be star HD 224544. Spectra were obtained at the Observatoire de Haute Provence, France, with a 0.2m telescope and a Lhires III spectrograph. The spectral coverage is 6485 – 6635 A with a resolution R~11000 and SNR ~ 25 in the continuum at H-alpha; the continuum was scaled in the interval 6600-6610A. The first observation started at 2014 Jul. 28.016UT and ended at 2014 Jul. 28.065UT, followed by a spectrum taken two nights later at 2014 Jul. 30.984UT and ended at 2014 Jul. 31.016UT. Compared to the spectrum in the BeSS database taken on 2013 Aug. 2.024UT, the H-alpha transitioned from absorption to a double-peaked emission line at an intensity level 1.35± 0.05 time above the continuum, indicating that an outburst occurred. The emission has a FWZI ~ 900 km/s with V/R ~ 1.0+/-0.1 with a velocity separation of about 300 km/s. The absorption feature is blueshifted by about 50km/s with a residual central intensity of about 5% above the continuum. The BeSS database contains 11 H-alpha spectra taken of this stars obtained in 2001, 2002, and one per year from 2008 to 2013 (and one ELODIE echelle spectrum from 2001 Dec. 2), resolution ~ 45000), all of which show only a pure absorption at H-alpha. All spectra are available in the BeSS database (Be Star Spectra, http://basebe.obspm.fr, LESIA – Observatoire de Paris-Meudon). Observations at other wavelengths are encouraged, as is submission of the data to the BeSS.

BeSS database v2.0