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Question
Hi,
My question is about when scientists discover an exoplanet around a distant star by means of measuring the amount of "wobble" of that star due to the gravitational pull of an orbiting planet. When a planet is found and they determine how many earth masses it is, how do they know that it is entirely the planet causing the wobble and not also moons of that planet? For example a planet that appears to be, lets say for example 15 earth masses, when really it could be 12 earth masses and have 6 large moons. Do they take that into account or is that more than they are able to determine at this time, or at least with that method?
Thank You
Hi Jason,
They are capable of separating the results of say, 2 eight-mass planets in different orbits around the star, but I think one planet with several smaller moons orbiting that planet... I think that is still beyond their capabilities. I've never heard of any moons of any exo-planets as yet being claimed to be discovered. (The combined mass of moons and planet would act as "one" in that case). Even all exo-planets to date are by stellar inference; we have yet to obtain a photograph of any exo-planet.
Clear Skies,
Tom Whiting
Erie, PA
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Answers by Expert:
Tom Whiting
Expertise
Astronomy has been my hobby/pasttime for over 50 years. Currently own 3 telescopes, the largest of which is a 30 inch Newtonian truss Dob that is portable.I taught Astronomy/Meteorology at the University Level for 13 years before retiring in 1995. Being retired and home most of the time, I am able to answer all questions relatively quickly, unless it's a new moon weekend with good observing conditions. No astrology questions please, or questions about alleged UFO picture identifications.
Experience
Experience: Astronomy has been my hobby and study for over 50 years. We currently now own a 30 inch portable telescope (Updated - Pennsylvania`s largest portable telescope). It can be seen on our website at:http://www.velocity.net/~bwhiting and also attend several regional starparties during the year, and have been on 5 total solar eclipse expeditions.
Organizations: President, Erie County Mobile Observers Group for over 15 years.
Publications: Wrote the "Over Erie Skies" newspaper article in our local newspaper for 11 years (1975-86).
Education: Masters Degree- Taught at the University level for 13 years. Retired 20 years -USAF Pilot - KC-135 with 180 combat missions; Also Eagle Scout, Philmont staff 2 Yrs, Order of Arrow Lodge Chief, Ham Radio (inactive).
Awards: two discoveries: The mini-coathanger asterism in Ursa Minor (the little dipper) And the mini-ladle- another asterism in the bowl of Ursa Minor. Clients: Currently President of the ECMOG as mentioned above.
Education/Credentials
BS Metallurgical Engineering Grove City College, PAMaster's Degree, Gannon University, Erie, PA
Also retired USAF pilot, 20 years.
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