Transcient in Cygnus

[Francois Teyssier]

Discovery at mag 9.2 : PSN J21040470+4631129 2019 07 12.4900* 21 04 04.70 +46 31 12.9 9.2 U Cyg 9 0
by by Hideo Nishimura, Shizuoka-ken, Japan

http://www.cbat.eps.harvard.edu/unconf/ ... 31129.html

Image 300 secondes with Echelle spectrograph R = 11000

NovaCyg2019.PNG (277.41 KiB) Viewed 17507 times

Send spectra to francoismathieu.teyssier at bbox.fr for ATel and inclusion in ARAS database

f

[Francois Teyssier]

...

Just a dwarf nova in outburst

FWHM (H alpha ) = 330 km/s and 1/2 FWZI = 500 km/s


Dommage

François

[Francois Teyssier]

The ATel:
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The Astronomer's Telegram http://www.astronomerstelegram.org

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ATEL #12936 ATEL #12936

Title: Echelle spectroscopy of TCP J21040470+4631129
Author: Francois Teyssier (ARAS Group, Rouen, France)
Queries: shore@df.unipi.it
Posted: 13 Jul 2019; 02:43 UT
Subjects:Cataclysmic Variable, Transient

We report optical echelle spectroscopy (R ~ 11000, 4100-7300A) the newly
reported transient TCP J21040470+4631129 (discovered on 2019 Jul.12.190
UT by Hideo Nishimura). The spectrum is consistent, obtains on 2019 Jul
12.9 UT (exposure time of 2589 sec, S/N ~ 40 hat 6100 A). The spectrum
is consistent with a large amplitude outburst of a cataclysmic variable.
The He I lines (e.g. 4471, 5013, 5876, 6678, 7065) all show symmetric
double peaks with separation 210 km/s (HWZI ~ 540 km/s). He II 4686 shows
peak separation of 310 km/s (but with there are also weak peaks coincident
with the He I lines) and broader wings, HWZI ~ 700 km/s; the redshifted
peak (+130 km/s) is slightly stronger and narrower. The profiles are centered
at 12 km/s but the wings show asymmetric extensions. The H-alpha and H-beta
profiles are asymmetric (R/V peak ~ 1.14±0.05) with separation of 160
km/s (HWZI = 600 km/s). There may be an absorption component at -30 km/s
(a similar minimum is seen on the He I lines) and H-beta and H-gamma show
an underlying broad absorption line that is redshifted relative to the
emission component by about 150±50 km/s, based on the profile asymmetry.
Additional emission includes the C III lines as a broad, featureless profile.
The precursor candidate noted in the CBAT report coincides with Gaia (DR2)
2163612727665972096 with parallax 9.134+/-0.116 (g=17.77 mag)

ARAS Spectral Database: http://www.astrosurf.com/aras/Aras_Data ... taBase.htm
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Password Certification: S. N. Shore (shore@df.unipi.it)
http://www.astronomerstelegram.org/?read=12936
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[Tim Lester]

My spectrum from a little later the same night.

Tim

[Francois Teyssier]

Impressive changes in a few hours

tcpj21040470+4631129_Ha.png (14.21 KiB) Viewed 17347 times

[Paolo Berardi]

Great observations and reactivity! Not a classical nova but I've never seen such a bright cataclysmic outburst!

A fresh spectrum with Lhires III 2400 (R~16000). Mag V ~9.1



A lot of change...

Paolo

[Robin Leadbeater]

Not a classical nova but I've never seen such a bright cataclysmic outburst!

Indeed! Are there other examples where the H alpha emission in a dwarf nova outburst completely dominates the absorption like this ? (an asymmetry and line of sight effect ?)

Cheers
Robin

[David Boyd]

Spectrum of TCP J21040470+4631129 taken on 13th July with a LISA spectroscope (R=1100) on a C11 and flux calibrated with concurrently measured mean magnitude V=9.14, B-V=-0.23.

tcpj21040470+4631129_20190713_928_D.Boyd.png (26.47 KiB) Viewed 17292 times

David

[Francois Teyssier]

Nice spectrum, David

Robin:
To my knowledge, this is the first time we get high res spectra of a DN in outburst
The change of the profiles reflect probably the orbital motion of the hot spot.
The profile is the combination of the disk in itself (about 20000 K) and the hot spot.

f

[Robin Leadbeater]

Hi Francois,

The line profile of the He II 4686 line might be interesting to follow. According to this paper it is associated with spiral structure in the disc
https://academic.oup.com/mnras/article/ ... 14/1079544

Cheers
Robin