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ASASSN-19de (TCP J06373299-0935420)

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Robin Leadbeater's picture
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ASASSN-19de (TCP J06373299-0935420)

This normally 19th mag star in Monoceros is currently at mag 10.3 (g) and still brightening. An R~500 ALPY spectrum taken last night shows a blue continuum with no H alpha line and H beta and higher Balmer lines in weak absorption. The spectrum can be viewed here

https://britastro.org/specdb/data_graph.php?obs_id=3925

and a current light curve and finder image is available here on the ASASSN website

https://asas-sn.osu.edu/light_curves/d99aa5e7-0b3f-4127-afbe-cd34192b0a67

Robin

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Identity

Hi Robin. Very interesting. Am I right in thinking this would be consistent with an accretion disk in an optically thick state? Or are there other - perhaps more likely - explanations?

Robin Leadbeater's picture
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CV spectra

Hi David,

I'm afraid I am not enough of an expert to interpret spectra of CVs, beyond being able to tell the difference between the spectrum of a classical nova and one of a dwarf nova. This is a typical spectrum of a dwarf nova in outburst. In this case a large amplitude outburst of a star with no previous history of outbursts so a likely WZ Sge (UGWZ)  type (I am reliant on Patrick Schmeer for this classification)

The source of the additional flux is impressively hot. The continuum fits to a ~35000K Planck curve, like an O star

Robin

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Image from Feb 24

Here's an image of it from last night. I get it to be 10.68 (using Gaia G and the green plane of this colour image)

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Image from 25 Feb, eve

Here's another image. As Nick's image shows, and indeed Robin's spectrum indicates, the object is very blue. I've uploaded a higher quality image to my member's page.

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Robin Leadbeater's picture
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Another spectrum last night

Another spectrum last night. It has cooled significantly (to ~15000K) and the Balmer absorption lines are more pronounced

Robin