ARAS Eruptive Stars

 

Symbiotic Stars Studies
BX Mon - Eclipse Egress 2022 - Draft

 

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Low resolution spectra secured by Forrest Sims (LISA R = 1000)

The two first spectra (JD 9644.658 & 9645.649) are represented in black and blue - Note the high consistency of the continuum.
The Ca II doublet appears in faint emission. Some faint lines are detected. See fig. x the identification in medium echelle spectrum

The emerging of the eclipse is detected with the spectrum acquired on JD 9654.669 (orange) with the first appareance of an increase of the blue continuum, disappearence of Ca II emission.
H beta appears in faint emission

 

 

 

Light curve - V band - Data: Forrest Sims, David Boyd

flat from JD9645 to 9655: the hot component is fully eclipsed.
almost linear from JD9655 to 9667: JD9655 marks the begining of the egress in V band.

TiO1 index (ref.)
Very similar to V curve, notably the plateau until JD 9654

The TiO index (0.80 +/- 0.02) measured during the total eclipse allows to determine the true spectral type of the RG: 5.7 - 5.8

 

Flux measured on the continuum f(B), f(V), f(R) at lambda = 4361, 5448, 6407 respectively on a 20 A range.

in units of 10^13 erg/s/cm^2

The flux ratios, measured on the continuum f(B), f(V), f(R) at lambda = 4361, 5448, 6407 respectiely, produce a new information and confirm the visual estimation from spectra (fg. 1): the blue continuum increases *before* the egress as determined from V lightcuve. If we assume a linear trend of the B/V ratio, it places the begining of the egress on JD ~ 9650.

While the V band luminosity continue to grow with a slower slope, after JD 9667, the flux ratio V/R is stable since JD 9667 and B/V declines strongly after a short plateau (JD 9667-69)

 

Note: the point JD9672 is probably underestimated

Todo:

Flux H alpha

 

 

Spectra can be downloded from ARAS Eruptive Stars Database: https://aras-database.github.io/database/bxmon.html

Observers in 2022: Forrest Sims (FAS), Joan Guarro (JGF), Franck Boubault (FBO), David Boyd (DBO)

 

Medium resolution spectra:

 

 

Long term monitoring

Database : 107 spectra (R = 500 to 11000) from 2011 to 2021

 

 

Dashed lines: ephemeris Fekel+,2000

 

 

 

References