Forum der Vereinigung der Sternfreunde :: Nova Sct 2017 eshel spectrum

Am 15.07.2017 um 11:16 schrieb Olivier GARDE :

Link zum neuen Beitrag: http://forum.vdsastro.de/viewtopic.php?t=4863#p29940

Hi everybody,

Last night, I was able to do the spectrum of Nova Sct 2017 in high
resolution R = 11000 with eshel spectrograph (11 exposures of 1200s
each, magnitude about 10.9)

Here's the "full" spectrum, we see a whole series of emission lines
with a P Cyg profil (probably type IV)
(1)

And the graphs of Balmer lines corrected from in heliocentrique
velocity of 7.1 km/s)

(2)

(3)

(4)

From these graphs we can measure the speed of expansion of the Nova and
we find the following values:
- H Alpha: -404.27 km/s (+/- 2.5 km/s)
- B Beta: -331.16 km/s (+/- 3.1 km/s)
- H Gamma: -325.31 km/s (+/- 3.5 km/s)

To see in the next days (if the magnitude of the nova not decrease too
much) how will these velocity evolve ?

(1) https://img4.hostingpics.net/pics/41161 ... 17full.png
(2) https://img4.hostingpics.net/pics/67701 ... 2017Ha.png
(3) https://img4.hostingpics.net/pics/63946 ... 2017Hb.png
(4) https://img4.hostingpics.net/pics/49842 ... 2017Hg.png

Autor:	Olivier GARDE [ 15. Juli 2017, 11:16:27 AM ]
Betreff des Beitrags:	Nova Sct 2017 eshel spectrum
Hi everybody, Last night, I was able to do the spectrum of Nova Sct 2017 in high resolution R = 11000 with eshel spectrograph (11 exposures of 1200s each, magnitude about 10.9) Here's the "full" spectrum, we see a whole series of emission lines with a P Cyg profil (probably type IV) And the graphs of Balmer lines corrected from in heliocentrique velocity of 7.1 km/s) From these graphs we can measure the expansion velocity of the Nova and we find the following values: - H Alpha: -404.27 km/s (+/- 2.5 km/s) - B Beta: -331.16 km/s (+/- 3.1 km/s) - H Gamma: -325.31 km/s (+/- 3.5 km/s) To see in the next days (if the magnitude of the nova not decrease too much) how will these velocity evolve ?

Autor:	Berthold Stober [ 15. Juli 2017, 14:55:03 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Great Oliver! Berthold Von meinem iPhone gesendet Zitat: Am 15.07.2017 um 11:16 schrieb Olivier GARDE : Link zum neuen Beitrag: http://forum.vdsastro.de/viewtopic.php?t=4863#p29940 Hi everybody, Last night, I was able to do the spectrum of Nova Sct 2017 in high resolution R = 11000 with eshel spectrograph (11 exposures of 1200s each, magnitude about 10.9) Here's the "full" spectrum, we see a whole series of emission lines with a P Cyg profil (probably type IV) (1) And the graphs of Balmer lines corrected from in heliocentrique velocity of 7.1 km/s) (2) (3) (4) From these graphs we can measure the speed of expansion of the Nova and we find the following values: - H Alpha: -404.27 km/s (+/- 2.5 km/s) - B Beta: -331.16 km/s (+/- 3.1 km/s) - H Gamma: -325.31 km/s (+/- 3.5 km/s) To see in the next days (if the magnitude of the nova not decrease too much) how will these velocity evolve ? (1) https://img4.hostingpics.net/pics/41161 ... 17full.png (2) https://img4.hostingpics.net/pics/67701 ... 2017Ha.png (3) https://img4.hostingpics.net/pics/63946 ... 2017Hb.png (4) https://img4.hostingpics.net/pics/49842 ... 2017Hg.png

Autor:	Olivier GARDE [ 29. Juli 2017, 13:20:07 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Collapse of the H alpha line on my last spectrum last night in comparison to the 3 other spectra obtained with the same set up since the 14th July.

Autor:	Thomas Eversberg [ 29. Juli 2017, 21:49:30 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Hi Olivier and Joan! Very nice work and highly interesting spectra. I am a bit surprised about the outcome because I would have expected a vice versa time order. As far as I understand novae the outbreak first produces an optically thick wind which makes a classical PCygni profile. After some days the wind becomes optically thin and produces a strong emission line without PCygni absorption. However, in your case the strong emission comes first. Why? Cheers, Thomas

Autor:	Thomas Eversberg [ 10. August 2017, 09:00:40 AM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Aha, now my question above is answered. The optically thick pCygni profile ("fireball") now more or less disappears and changes to the optically thin (almost) pure emission line (expanding cloud). So, the above profiles from the end of July come from the fireball period. The central reversal right at about -300km/s is very interesting, though. It seems to be a kind of self-absorption due to additional material in the line-of-sight. Cheers, Thomas

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Autor:	Olivier GARDE [ 13. August 2017, 13:41:20 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Here's my last spectrum taken last night. Comparison with the last echelle spectrum of Joan (taken in the ARAS data base) And Balmer lines (H Alpha and H Beta)

Autor:	Berthold Stober [ 13. August 2017, 20:11:59 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Hi Joan I am very impressed by your splendid spectra of such a week object like this nova. I use an eShel from shelyak with a telescope C14 , a little bit smaller than yours. I don't believe that I can create such spectra , such impressive spectra of such a week star. Have you any tricks, with guiding for instance? I use PHD FOR GUIDING but it is not so easy to hold the star in the center of the fiber. Could you tell me some details how you get those spectra? Berthold

Autor:	Berthold Stober [ 14. August 2017, 22:10:21 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Thank you very, Joan, much for this Information . Very interisting But my fiberinjection from Shelyak has no slit !. Friendly Berthold

Autor:	Joan Guarro Flo [ 14. August 2017, 23:09:42 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Hallo Berthold, I know that your fiber does not have a slit, I think, yours has a reflective glass, (to be able to do the guide), with a pinhole. I and I have the same reflective glass, (also from the Shelyak house), but with a slit of 75 microns. Some time ago I bought these slits at the Shelyak house and I took them for the echelle. The slit is not very annoying and I can orintate it very well, in the North-South direction. The optical fiber I use is like the one you have, 50 microns. In the guide module I only use a single fiber (the one of, 50 microns), since the calibration and tungsten lamps are in the same guide module. Regards, Joan.

Autor:	Olivier GARDE [ 15. August 2017, 08:14:30 AM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Halo Berthold, I have also an eshel spectrograph and I do auto guiding with Maxim DL 6. I can auto guiding directly on the target into the fiber very well (3200mm local length) with less than 0,2 pixel peak error and RMS about 0,1 (guiding with an ATIK 314L+ in binning 2x2) and it works also with faint target like this nova (but with 3s exposure). Before night, I just check the coordinate of the fiber X and Y and put this coordinate as a consign for auto guiding in Maxim DL. I have an AP1600 mount and the polar align is less than 45'' off the pole.

Autor:	Berthold Stober [ 18. August 2017, 21:31:01 PM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
Great indeed! Joan! Friendly Berthold

Autor:	Olivier GARDE [ 12. September 2017, 11:40:58 AM ]
Betreff des Beitrags:	Re: Nova Sct 2017 eshel spectrum
An Atel on Nova Sct 2017 about some amateur spectra from ARAS database (amateur from Spain, France, USA, Australia, Italy) http://www.astronomerstelegram.org/?read=10737

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