Symbiotic Star StHa 32

Information about outbursts of eruptive stars, Be activity, ...

Symbiotic Star StHa 32

Postby Francois Teyssier » Thu Mar 01, 2018 12:08 pm

Symbiotic StHa 32 is in outburst at mag V ~ 12.5
Nice target for low resolution (not yet in the database)

The ATel :

The super-soft X-ray and CH/Ba-enhanced symbiotic star StHa 32 is in outburst

ATel #11304; U. Munari (INAF Padova), S. Dallaporta, M. Graziani, G. L. Righetti, S. Tomaselli, S. Moretti, A. Maitan, F. Castellani, P. Valisa, L. Baldinelli (ANS Collaboration)
on 15 Feb 2018; 11:12 UT


The supersoft X-ray source, Barium-enhanced, metal-deficient and Halo symbiotic star StHa 32 in going into outburst, the first ever recorded to the best of our knowledge.

We are intensively following StHa 32 both photometrically and spectroscopically since 2005. Its photometric behavior in B band begun to deviate from the P=626 days orbital modulation at the beginning of November 2017. The initial rise has been very slow, gaining pace with passing time. The following are some of our most recent measurements:


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The brightness gain in B band is already 0.85 mag compare to quiescence value at the same orbital phase, with all colors turning bluer.

A low resolution spectrum (3300-8000 Ang, 2.31 Ang/pix) has been obtained on UT Feb 14.8 with the Asiago 1.22m. Comparing with similar archive spectra obtained in quiescence at exactly the same orbital phase, the major differences are: (1) a brighter and bluer continuum at shorter wavelengths, with enhanced veiling of the absorption features of the cool giant (in particular the C2 bands at 4740, 5165 Ang, and the CH band at 4303); (2) a large increase in the integrated absolute flux of all emission lines; (3) a large increase in the ionization degree: HeII 4686/Hbeta changing from 1.45 to 2.15, HeII 4686/HeI 5016 from 15 to 28, OVI 6825/HeI 6678 from 1.35 to 2.32. No obvious nebular line is present (in particular [FeVII] and [NeV]). This is consistent with a high density, density-bounded nebula increasingly ionized by a now hotter and more luminous WD. Still, enough neutral hydrogen survives in the system to be able to efficiently Raman scatter OVI 1032, 1036 to observed 6825 and 7088 Ang (the latter 0.38 times the intensity of HeI 7065).
Francois Teyssier
 
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Re: Symbiotic Star StHa 32

Postby Forrest Sims » Fri Mar 02, 2018 5:49 am

Greetings!
I had a go at StHa 32 tonight. The full Moon was not ideal but the target and reference stars were not at all close to the Moon. I took (8) 300sec guided exposures of StHa 32. I took (7) 30 sec exposures of the Miles star HD041692 for determination of the instrument and atmospheric response curve correction. All of the emission lines in the spectrum appear red shifted.

Comments appreciated:)

Woody
Attachments
stha32_20180302_105_Forrest Sims annotated.png
Forrest Sims
 
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Re: Symbiotic Star StHa 32

Postby Francois Teyssier » Fri Mar 02, 2018 6:41 am

That's great Woody! A new symbiotic in the database
You have also intense Raman OVI bands, so the ionization level remains very high >> 100 000 K
P Cygni profiles on the lower members of Balmer lines
It looks to be an outburst of an accretion disk around the white dwarf
François

Of course monitoring of the outburst is welcome
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Re: Symbiotic Star StHa 32

Postby Francisco Campos » Wed Mar 07, 2018 7:59 pm

Hello,

my contribution, not as good as Forrest's one, but still valuable, I hope...

_stha32_20180305_799_FPC.png
_stha32_20180305_799_FPC.png (7.84 KiB) Viewed 568 times


Greetings,
Fran
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