98-BLG-35 - Why not featuring?

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98-BLG-35 - Why not featuring?

Post by Edasich on 20th April 2010, 11:39 am

I was wondering why 98-BLG-35 planet is not listed amongst microlensing candidate exoplanets.
Orbital solution is not 100% as robust as microlensing exoplanets announced by MOA team, nonetheless I'd like to show you this excerpt from the latest article concerning 98-BLG-35, dated back 2002:

Planetary modelling of the three events was carried out in a supercluster computing environment. The estimated probability for explaining the data on MACHO 98-BLG-35 without a planet is <1 per cent. The best planetary model has a planet of mass ~(0.4-1.5)×MEarth at a projected radius of either ~1.5 or ~2.3au.

There is no further work (as far as I know) discarding the planetars either setting tighter limits for planetary objects.
So why is it not listed at EPE, between exoplanets?

Same for other microlensing planets left: 94-BLG-4 and 95-BLG-3.

If someone has more infos, please contribute. Thanks. Wink
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Re: 98-BLG-35 - Why not featuring?

Post by Sirius_Alpha on 20th April 2010, 1:08 pm

While I'm not 100% sure, it seems there is some ambiguity on whether the microlensing events are attributable to a planet or not. From the standpoint of Occams razor, there's no apparent reason to believe a planet model over a stellar model.

Maybe someone that knows more on the issue would offer more information.

From here:
The PLANET team data for the
microlensing event MACHO 98-BLG-35 are well-explained by a single lens; we do not confirm the evidence for a possible planet orbiting the lens reported by other researchers. To date, the PLANET team has detected no planetary signatures in 43 microlensing events, implying that no more than 1/3 of the most typical stars in the Galaxy can have Jupiter-mass planets orbiting between 1.5 and 4 AU. (One AU is the distance between the Earth and its Sun.) To read more about this result, download our technical paper.

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Re: 98-BLG-35 - Why not featuring?

Post by Lazarus on 20th April 2010, 1:29 pm

I think for quite a lot of these early microlensing candidates there isn't enough data of good enough quality to make firm conclusions. It wasn't until the observation strategy was refined that solid detections started to be made.
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Re: 98-BLG-35 - Why not featuring?

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