P Cygni & VV Cep

Back from our Shelyak Instruments annual spectroscopy workshop at Observatory of Haute Provence with around 50 spectroscopists from all over the World! We had a really great time, in a very friendly atmosphere but also some great observing time (wetaher was not perfect but ok for such workshop) and exceptionnal talks including a course from Steve Shore!

Tonight (21-aug-2015), I opened the observatory and observed P Cygni, a Luminous Blue Variable star with very strong wind and a typical line profile called "P Cygni profile" with a blue absorption on the side of an emission line - very strong in the case of Halpha in P cygni itself.


The night was excellent with very good seeing and a sky background magnitude around 20.5 at zenith. I first focused the telescope:

I then pointed toward P Cygni and recorded several spectra:

Here is the telescope under the dome during this acquisition:

I then took spectra of a reference star (hd198183) which I reduced to get my instrumental response for that night, at that air mass:

ISIS results for wavelength calibration (23 orders of the Shelyak Instruments eShel echelle spectrograph):

Ordre #31 :   RMS = .0014   -   Nb. raies = 7
Ordre #32 :   RMS = .0151   -   Nb. raies = 10
Ordre #33 :   RMS = .0221   -   Nb. raies = 12
Ordre #34 :   RMS = .0084   -   Nb. raies = 15
Ordre #35 :   RMS = .0090   -   Nb. raies = 15
Ordre #36 :   RMS = .0069   -   Nb. raies = 16
Ordre #37 :   RMS = .0049   -   Nb. raies = 14
Ordre #38 :   RMS = .0067   -   Nb. raies = 15
Ordre #39 :   RMS = .0100   -   Nb. raies = 17
Ordre #40 :   RMS = .0082   -   Nb. raies = 15
Ordre #41 :   RMS = .0159   -   Nb. raies = 19
Ordre #42 :   RMS = .0188   -   Nb. raies = 15
Ordre #43 :   RMS = .0105   -   Nb. raies = 16
Ordre #44 :   RMS = .0112   -   Nb. raies = 17
Ordre #45 :   RMS = .0057   -   Nb. raies = 16
Ordre #46 :   RMS = .0090   -   Nb. raies = 15
Ordre #47 :   RMS = .0090   -   Nb. raies = 12
Ordre #48 :   RMS = .0061   -   Nb. raies = 14
Ordre #49 :   RMS = .0154   -   Nb. raies = 13
Ordre #50 :   RMS = .0024   -   Nb. raies = 9
Ordre #51 :   RMS = .0123   -   Nb. raies = 10
Ordre #52 :   RMS = .0176   -   Nb. raies = 12
Ordre #53 :   RMS = .0461   -   Nb. raies = 11
Résolution :
Ordre #31 :  FWHM = 4.44  -  Dispersion = .195 A/pixel  -  R = 8371.5
Ordre #32 :  FWHM = 4.97  -  Dispersion = .187 A/pixel  -  R = 7541.3
Ordre #33 :  FWHM = 4.31  -  Dispersion = .185 A/pixel  -  R = 8512.7
Ordre #34 :  FWHM = 4.01  -  Dispersion = .179 A/pixel  -  R = 9175.9
Ordre #35 :  FWHM = 3.74  -  Dispersion = .174 A/pixel  -  R = 9841.9
Ordre #36 :  FWHM = 3.47  -  Dispersion = .169 A/pixel  -  R = 10644.1
Ordre #37 :  FWHM = 3.50  -  Dispersion = .163 A/pixel  -  R = 10609.0
Ordre #38 :  FWHM = 3.31  -  Dispersion = .161 A/pixel  -  R = 11117.8
Ordre #39 :  FWHM = 3.17  -  Dispersion = .158 A/pixel  -  R = 11493.8
Ordre #40 :  FWHM = 3.42  -  Dispersion = .153 A/pixel  -  R = 10754.0
Ordre #41 :  FWHM = 3.28  -  Dispersion = .148 A/pixel  -  R = 11263.6
Ordre #42 :  FWHM = 3.39  -  Dispersion = .145 A/pixel  -  R = 10871.7
Ordre #43 :  FWHM = 3.05  -  Dispersion = .145 A/pixel  -  R = 11760.6
Ordre #44 :  FWHM = 3.19  -  Dispersion = .140 A/pixel  -  R = 11408.9
Ordre #45 :  FWHM = 3.27  -  Dispersion = .136 A/pixel  -  R = 11267.4
Ordre #46 :  FWHM = 3.36  -  Dispersion = .133 A/pixel  -  R = 10889.0
Ordre #47 :  FWHM = 3.47  -  Dispersion = .129 A/pixel  -  R = 10694.9
Ordre #48 :  FWHM = 3.43  -  Dispersion = .126 A/pixel  -  R = 10791.9
Ordre #49 :  FWHM = 4.14  -  Dispersion = .125 A/pixel  -  R = 8883.3
Ordre #50 :  FWHM = 4.37  -  Dispersion = .119 A/pixel  -  R = 8598.7
Ordre #51 :  FWHM = 4.70  -  Dispersion = .115 A/pixel  -  R = 8130.8
Ordre #52 :  FWHM = 5.18  -  Dispersion = .115 A/pixel  -  R = 7260.5
Ordre #53 :  FWHM = 5.62  -  Dispersion = .113 A/pixel  -  R = 6689.2

P Cygni profile shows very nice emission lines:

Here is a zoom around Halpha and He I 6678 neutral helium emission line:

My next target is VV Cep, a spectroscopic binary system of great interest as the hot companion surrounded by an accretion disk will be eclipsed by the red supergiant primary star in 2017-2018. This very rare (every 20.4 years) event will be an unique opportunity to "see" the primary huge chromosphere as the hot star light through it like a flash light. It will be a continuous target for my observatory hopefully in the next few years to come!

The overall spectrum shows all the molecular bands (TiO), typical for a red supergiant star (such as Betelgeuse for exemple) but it also display emission line coming from ionized region by the hot companion.

A zoom on Halpha shows a very nice double peak with the V (blue) peak higher than the R (red) one. The two peaks are split by about 130km/s. An article by Kawabata in 1981 gives 170km/s for outside eclipse separation and 120km/s during eclipse - obviously this emission line is not stable over time