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Fast moving White Dwarf

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Jeremy's picture
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Fast moving White Dwarf

Professor Boris Gaensicke (U of Warwick), a great friend of the Variable Star Section, was interviewed on the BBC Today programme this morning. He was speaking about a fast moving white dwarf which he thinks might have been ejected from a partial supernova. You can hear it on BBC Sounds catch-up, starting at 1 h 44 minutes into the programme.

The MNRAS paper on “SDSS J124043.01+671034.68: The partially burned remnant of a low-mass white dwarf that underwent thermonuclear ignition?” reporting the discovery is here.

A popular account in Forbes magazine is here.

It’s not often ones gets to listen to an item on white dwarfs on national radio over cornflakes and marmalade!

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Morning reading and listening

Thanks Jeremy (although I'm slightly disturbed by the juxtaposition of marmalade and cornflakes). On a hilarious note, please read this article published yesterday:

https://www.dailymail.co.uk/debate/article-8523421/Has-star-sign-wrong-along.html

Apparently NASA discovered Oph just a few years ago. And what exactly has C/2020 F3 (NEOWISE) got to do with anything in relation to the rest of the article? A hoot.

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What a complete load of b*****

David, I hold you personally responsible that I now have to hoover out my keyboard after reading that Daily Mail article while eating my lunchtime sandwich. Do they actually pay their astrologer to write this stuff? I have to admit though that "Comet Neowise" is certainly having a significant influence on my life at the moment.

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Hilarious

Thanks David. I am glad you are maintaining your catholic tastes in print media. What a crazy article! I always remember Patrick citing Oph as the 13th sign of the zodiac in his debunking of astrology.

BTW, Cornflakes and marmelade was my inclusive short-hand for breakfast, which in my case is "Dorset cereals seriously nutty muesli", with banana, blueberries, low fat Greek yoghurt, and semi-skimmed milk, but I thought that might sound a bit too bourgeoisie. 

Jeremy's picture
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BBC

We can relax now because the BBC has the definitive news item on its website and this object.

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Run-away white dwarf

SDSS 124043.01+671034.68 is relatively bright at Gaia g=18.44 so I'll see whether I can take an image when I'm back at my observatory in a week or so.  There is a g=12.68 star 15 arcsec distant and I hope that the scattered light from it won't cause too many problems.

Watch this space.

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Imaged

Tonight was the first session of this stay in La Palma. I imaged the field and there is something there but the WD is rather drowned out by the bright star.

Not a very good night with some moon-lit haze and high winds, which makes for poor seeing at this site. The relatively low altitude of the star (30-33 degrees tonight) at this latitude most certainly does not help.

I will process the data tomorrow and see whether there is anything worth posting.

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Not wonderful ...

As expected, the image is not very good. The 19 minute exposure in ~5 arcsec FWHM seeing was not long enough for an 18.4 magnitude object  only 15 arcsec from a star six magnitudes brighter.

The position of the WD is marked, the star is just about visible but not obvious. For comparison a snippet of the DSS2 image is included. The fainter (north-easternmost) star between the two brightest is mag 17.8 in Gaia DR2. The poor seeing is especially well demonstrated by the inability to resolve the ~6 arcsec double which is visible in the DSS2 image.

I will try again with a longer exposure in much better seeing conditions before uploading to my personal web page.

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WD imaging

Good effort though, Paul. I look forward to seeing the definitive result when conditions have improved.

Xilman's picture
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Conditions

So do I. The calimas around here have been dreadful recently. Last night had noticeably better seeing but poor transparency. Saharan dust and a full moon are not conducive to good imaging. Some more data was taken, down to an altitude of 20 degrees this time, but my expectations are not high.

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White Dwarf

So BAA is an acronym for Breakfast Appreciation Association 

Jeremy's picture
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A good start

A good start Paul. Hope you get better conditions that will allow you to go a bit deeper on this target.