Long-period brown dwarfs from SOPHIE

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Long-period brown dwarfs from SOPHIE

Post by Lazarus on 30th November 2015, 5:39 pm

Bouchy et al. "The SOPHIE search for northern extrasolar planets VIII. Follow-up of ELODIE candidates: long-period brown-dwarf companions"
http://arxiv.org/abs/1511.08397

Under the Hatzes & Rauer criterion, most of them would be considered planet candidates.
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Re: Long-period brown dwarfs from SOPHIE

Post by Shellface on 30th November 2015, 6:37 pm

Under the Hatzes & Rauer criterion, most of them would be considered planet candidates.
I know, this isn't the right place… but are we really going to blithely assume that because the radii distribution of objects in the ~0.3 - 70 Mjup interval is close to constant, there is no physical distinction between giant planets and brown dwarfs?

The notion is bizarre to me… that's a span in densities of over 2 orders. Can even a layman not hypothesise that this may cause structural differences? Does that not count for anything? Is there nothing that can be taken from the Herculean efforts it took to properly understand the relationship between stellar structure and the H-R diagram?


Regardless. I'm quite a fan of studies of brown dwarf companions, and that plus seeing the continuing use of ELODIE data after almost a decade since its decommissioning was pleasant to see.

It's rather remarkable that the orbital fit for HD 18757 is so well-constrained, considering how little of the orbit is covered. I suppose that's a testament to good periastron coverage.

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Re: Long-period brown dwarfs from SOPHIE

Post by Stalker on 1st December 2015, 4:38 am

Shellface wrote:there is no physical distinction between giant planets and brown dwarfs?

No, not at the boundary. Of course a 1Mj planet and a 60Mj BD are different objets. The BD would be still very hot after severa billion years and almost totally degenerate, but between the two there is no boundary dependent of the deuterium burning mass limit. for example, the birth of a degenerate core occure at 4-5 Mj, well inside the conservative planetary domain.

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Re: Long-period brown dwarfs from SOPHIE

Post by Edasich on 8th January 2016, 4:23 pm

I'm not sure it's the most suitable thread, but...

Another brown dwarf listed at EPE:

http://exoplanet.eu/catalog/hd_19467_b/
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Re: Long-period brown dwarfs from SOPHIE

Post by Edasich on 10th February 2016, 6:23 am

Some possible RV-detected exoplanet candidates according to the planet-BD mass limit selected.

The SOPHIE search for northern extrasolar planets IX. Populating the brown dwarf desert

Radial velocity planet search surveys of nearby Solar-type stars have shown a strong deficit of brown dwarf companions within ∼5AU. There is presently no comprehensive explanation of this lack of brown dwarf companions, therefore, increasing the sample of such objects is crucial to understand their formation and evolution. Based on precise radial velocities obtained using the SOPHIE spectrograph at Observatoire de Haute-Provence we characterise the orbital parameters of 15 companions to solar-type stars and constrain their true mass using astrometric data from the Hipparcos space mission. The nine companions not shown to be stellar in nature have minimum masses ranging from ~13 to 70MJup, and are well distributed across the planet/brown dwarf mass regime, making them an important contribution to the known population of massive companions around solar-type stars. We characterise six companions as stellar in nature with masses ranging from a minimum mass of 76±4MJup to a mass of 0.35±0.03M⊙. The orbital parameters of two previously known sub-stellar candidates are improved.

Plus, couldn't this and other similar topics about SOPHIE detections be merged in a single "SOPHIE results" thread?
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