Gaia19bpg

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Jaroslav Merc
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Joined: Thu May 04, 2017 11:27 am
Location: Prague, Czech Republic
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Gaia19bpg

Post by Jaroslav Merc »

Hello everyone,

I am resubmitting here my post from the forum thread on the suspected and misclassified symbiotics as it seems that the object is very interesting and its spectroscopic observation might be time-critical. The working hypothesis is, that the object might be a symbiotic nova or a symbiotic star similar to BX Mon (based on the Halpha line profile). It is Gaia19bpg (G ~ 14; RA 21:41:50.43, DEC +51:55:45.48) located in Cygnus (window for observations is getting shorter everyday...). As I mentioned previously, the target was picked up by colleagues from Hungary who study young stellar objects (but it is not a YSO). They obtained two low-res spectra in 2019 and 2020 and a medium-res spectrum covering Halpha in 2021. We also have IR spectra which confirmed that the cool component is a giant star, excluding possible red dwarf classification.

Its outburst started at the turn of 2018 and 2019, you can find the recent Gaia light curve here: http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpg/. Recently the brightness has begun to drop, however, it seems, that the decrease stopped. That may suggest that the outburst is not over and that the drop in brightness was caused by some eclipse-like process. During the decrease of brightness, the Halpha line strengthens significantly in Gaia (very)-low-res spectra.

It would be great if we would have an observation (a low-res optical spectrum covering as wide range of wavelengths as possible) while the star is not back at the maximum of light (if this would happen). After the star will return to maximum (if this would happen), probably only next year at the beginning of the season, another low-res spectrum going as far as possible to near-UV to see the Balmer jump (if it is in emission or absorption) would be extremely useful. Anytime, the spectrum of Halpha with higher resolution to study the profiles would be very welcomed (spectrum which we already have shows an emission line with a strong absorption component).

Jaroslav
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