Spokane Falls Community College ASTRONOMY 101 LAB 5

Access the lab content at
http://astro.unl.edu/naap/esp/esp.html Name: _________________ _____


Extrasolar Planets
Remember to type your answers in blue text

Background Material
Complete the following sections after reviewing the background pages entitled Introduction,
Center of Mass, The Doppler Effect, and Detecting ExtraSolar Planets.
Question 1: In the boxes provided, label the positions on the star’s orbit with the letters
corresponding to the labeled positions of the radial velocity curve. Radial velocity is positive
when the star is moving away from Earth and negative when the star is moving towards Earth.




m
er as
B




co
eH w
A C




o.
rs e D
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Question 2: Label the positions on the planet’s orbit with the letters corresponding to the
o
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labeled positions of the radial velocity curve. Hint: the radial velocity in the plot is still that of
vi y re



the star, so for each of the planet positions determine where the star would be and in which
direction it would be moving.
C
ed d
ar stu
is




D B
Th
sh




A
Part I: Exoplanet Radial Velocity Simulator
Introduction
Open up the exoplanet radial velocity simulator. You should note that there are several distinct
panels:

NAAP – ExtraSolar Planets 1/8
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,  a 3D Visualization panel in the upper left where you can see the star and the planet
(magnified considerably). Note that the orange arrow labeled earth view shows the
perspective from which we view the system.
o The Visualization Controls panel allows one to check show multiple views. This
option expands the 3D Visualization panel so that it shows the system from three
additional perspectives.
 a Radial Velocity Curve panel in the upper right where you can see the graph of radial
velocity versus phase for the system. The graph has show theoretical curve in default
mode. A readout lists the system period and a cursor allows you to measure radial
velocity and thus the curve amplitude (the maximum value of radial velocity) on the
graph. The scale of the y-axis renormalizes as needed and the phase of perihelion (closest
approach to the star) is assigned a phase of zero. Note that the vertical red bar indicates
the phase of the system presently displayed in the 3D Visualization panel. This bar can be
dragged and the system will update appropriately.




m
 There are three panels which control system properties.




er as
co
o The Star Properties panel allows you to control the mass of the star. Note that




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the star is constrained to be on the main sequence – so the mass selection also
determines the radius and temperature of the star.




o.
rs e
o The Planet Properties panel allows you to select the mass of the planet, the semi-
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major axis, and the eccentricity of the orbit.
o The System Orientation panel controls the two perspective angles.
o

 Inclination is the angle between the Earth’s line of sight and the plane of
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the orbit. Thus, an inclination of 0º corresponds to looking directly down
vi y re


on the plane of the orbit and an inclination of 90º is viewing the orbit edge
on.
 Longitude is the angle between the line of sight and the long axis of an
ed d




elliptical orbit. Thus, when eccentricity is zero, longitude will not be
relevant.
ar stu




 There are also panels for Animation Controls (start/stop, speed, and phase) and Presets
(preconfigured values of the system variables).
is
Th
sh




NAAP – ExtraSolar Planets 2/8

This study source was downloaded by 100000793680026 from CourseHero.com on 07-05-2021 04:46:37 GMT -05:00


https://www.coursehero.com/file/13610503/LAB-5-ASTR/