B MARVELS Discovery: 1 Giant Planet & 'Failed Star' Found

[wolram]

Date:
October 19, 2016
Source:
University of Florida
Summary:
Everything we know about the formation of solar systems might be wrong, says two astronomers. They've discovered the first "binary--binary" -- two massive companions around one star in a close binary system, one so-called giant planet and one brown dwarf, or "failed star" The first, called MARVELS-7a, is 12 times the mass of Jupiter, while the second, MARVELS-7b, has 57 times the mass of Jupiter.

Edit for link, Vhttps://[URL="http://www.sciencedaily.com/releases/2016/10/161019162507.htm"]www.sciencedaily.com/releases/2016/10/161019162507.htm[/URL]

 

[mfb]

With a single example. it could always be the result of some freak encounter of a system with objects from elsewhere that got caught. And the system is clearly completely different from ours, i don't see why models describing that well should have such a huge impact on models that work for our solar system.

 

[Chronos]

I call bullshit. This is just another misdirection.

 

[|Glitch|]

Date:
October 19, 2016
Source:
University of Florida
Summary:
Everything we know about the formation of solar systems might be wrong, says two astronomers. They've discovered the first "binary--binary" -- two massive companions around one star in a close binary system, one so-called giant planet and one brown dwarf, or "failed star" The first, called MARVELS-7a, is 12 times the mass of Jupiter, while the second, MARVELS-7b, has 57 times the mass of Jupiter.

Edit for link, Vhttps://[URL='http://www.sciencedaily.com/releases/2016/10/161019162507.htm']www.sciencedaily.com/releases/2016/10/161019162507.htm[/URL][/QUOTE]
First of all, they have some serious naming issues. They continuously refer to the binary system as HD 87646, when they should be referring to it as HD 87646AB. Second, they do not identify which star the brown dwarf and the other massive exoplanet orbit. If they are both orbiting the biggest G spectral type star then they should be named HD 87646Ab and HD 87646Ac respectively. If both the brown dwarf and the massive exoplanet orbit the smaller K spectral type star, then they should be named HD 87646Bb and HD 87646Bc respectively. As their paper stands, there is confusion as to which star the brown dwarf and the massive exoplanet are orbiting.

Secondly, having two main sequence stars in a close binary orbit is not that unusual. Alpha Centauri AB is an example of two main sequence stars (a G and K spectral type, just like HD 87646AB as it happens) in a close binary orbit. Separated by only 23.625 ± 0.055 AU Alpha Centauri AB are pretty close to the same amount of separation between HD 87646AB, which is ~22 AU.

Lastly, I do not understand how this discovery would have any effect on our understanding of solar system formation. It is not a "binary-binary" system, as that would require two sets (or four) stars/brown dwarfs orbiting one another (of which there are already numerous examples, so this is certainly not the "first" as they claim). At best, HD 87646AB is a tertiary system and should therefore be named HD 87646AB-C, similar to Alpha Centauri AB-C (when Proxima Centauri is included).

Source:
Very Low-Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS VI: A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646 - arXiv 1608.03597