The Mystery of WASP-18b: Uncovering the Mass and Rotation of Its Mother Star

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Discussion Overview

The discussion revolves around the mass and rotation speed of the mother star of the exoplanet WASP-18b. Participants explore various claims and data regarding the characteristics of the star, as well as the implications of these properties on the planet itself.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant mentions finding a mass for WASP-18b of "roughly 10 times the mass of Jupiter," but later corrects this to indicate they were referring to the planet itself, not the mother star.
  • Another participant calculates the mass of the mother star to be approximately 1.2 solar masses based on the period and distance of WASP-18b, suggesting it is a sun-like star.
  • A different participant suggests a mass of 1.25 times that of the Sun and states that the rotation period of the star is about 5.6 days.
  • There is a query about how to calculate the tidal effects on WASP-18b, with a claim that the planet is expected to be 28 seconds faster in its orbit over the next decade due to these effects.
  • One participant challenges the existence of WASP-18 and its associated exoplanet, citing a lack of listings from NASA and questioning the validity of the claims made about the star and planet.

Areas of Agreement / Disagreement

Participants express differing views on the existence and properties of the mother star of WASP-18b, with some providing calculations and others questioning the validity of the information. There is no consensus on the mass or rotation speed of the star, nor on the existence of WASP-18 itself.

Contextual Notes

Some claims rely on specific assumptions about the calculations of mass and rotation, and there are unresolved questions regarding the sources of information about WASP-18 and its exoplanet. The discussion reflects uncertainty about the validity of the star's designation and the data presented.

Bjarne
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Does someone know the mass of the mother star WASP-18b is circling around as well as the rotation speed?
 
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The only mass i could find for it was "roughly 10 times the mass of jupiter" from this article (http://www.skyandtelescope.com/news/55066637.html ).

As for rotation speed, the only thing i saw is that it rotates inward and has an orbit time of around 22.5 hours.

EDIT: oops. didn't see mother star. facts above are for WASP-18b, sorry.
 
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Bjarne said:
Does someone know the mass of the mother star WASP-18b is circling around as well as the rotation speed?

Given the period of WASP-18b, and its distance (~.02 AU), I come up with a mass for the star of 1.2 solar masses, which agrees with the articles which say that it is a sun-like star.
 
Janus said:
Given the period of WASP-18b, and its distance (~.02 AU), I come up with a mass for the star of 1.2 solar masses, which agrees with the articles which say that it is a sun-like star.

I just hear 1.25 times that of the Sun, so Janus you are very close.
And I hear one rotation: 5.6 days

How can the tide effect on that planet be calculted?.
(I have read that it is so strong what we expect the planet will be be 28 seconds faster in the next decade.)
 
NASA does not list a star with exoplanets with the designation WASP-18:
http://nsted.ipac.caltech.edu/index.html

Nor was there an exoplanet that came to light in 2006 with a mass of ten Jupiters.
http://planetquest.jpl.nasa.gov/atlas/atlas_search.cfm?&Sort=DiscDate&SortDir=DESC

or that has the designation WASP-18b.
So you have a story about an unknown exoplanet that orbits a star that doesn't exist.
Maybe that is the mystery?
 
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