SU Lyn radial velocity

[Francois Teyssier]

I'm begining to work on the radial velocity of the red giant in this newly discovered symbiotic.
Ramsay & al. (2016) proposed a M5.8III type for the cool star (correction 13-04-2017)

I got a spectrum of VY Leo = 56 Leo (Mag V = 5.8 and rv = -8.4 km/s). This star is used as reference in Müerset & Schmidt (1999) : Spectral classication of the cool giants in symbiotic systems

The spectra of SU Lyn and VY Leo are corrected for heliocentric velocity,
then the spectrum of VY Leo is shifted of 8.4 km/s using ISIS.

I work on a crop of the spectrum [5000..5151]

Here's teh comparisation of the two spectra, showing the radial vélocity of SU Lyn

Computation with ISIS Radial velocity gives a vlaue of -18.0 km/s for 02-04-2017. I estimate the error at ~ 1 km/s

More data will produce the radial velocity of the system and the orbital varaition of the red giant.


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Then, I shift the spectrum of SU Lyn of +18 km/s

This give access to the (currently) very faint emission lines

H beta

sulyn_ 20170402_814_hb.png (65.55 KiB) Viewed 5014 times

[OIII]

sulyn_ 20170402_814_oiii.png (52.37 KiB) Viewed 5014 times

Then, we can get the real value of the intensities of the lines after substraction of the psesudo continuum of VY Leo from the spectrum of SU Lyn



Na I D range, with interstellar absorptions of D1 D2 and the absorptions of the symbiotic nebula

sulyn_ 20170402_814_NaID.png (44.21 KiB) Viewed 5014 times

Matche well:

sulyn_ 20170402_814_4800.png (51.77 KiB) Viewed 5014 times

François


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[Andrew Smith]

Hi François, very nice work.

I am trying to get a better understanding of RV techniques and find what you have done here using a reference star very interesting. I will follow up the reference.

I have two questions, firstly what spectroscope did you use and secondly, how did you estimate the 1 km/s error?

Regards Andrew

PS With my fiber fed echelle with temperature controlled to about +/- 0.05 C I measure a stability of +/- 0.37 km/s of the TH Ar lamp lines over several hours.

[Francois Teyssier]

Hi Andrew,

This an Shelyak eShel

I estimated the error from a previous work on EG And radial velocity and a comparisation with published value
At the date, my eshel is not yet regulated in temperature ; it is just placed in an isothermal box.
I'm working on the regulation.
I envisaged a cooling box (not regulated) and inside a regulated heating box.
I also work on a pressure contro, slightly above the atmospheric pressure

Could you, please, update the presentation of your *excellent* temperature control

All the best,

François

[Paolo Berardi]

Great work François!

Can you show the results of the profiles subtraction?

Paolo

[etienne bertrand]

Bravo pour ce résultat.