Astrophysics (Index)About

transit

(a celestial body passing between another and an observer)

A transit is the passage of an astronomical body between an observer and another astronomical body, generally used when the nearer body blocks only a bit of the further body, i.e., the further body occupies a larger portion of the celestial sphere, appearing larger; the terms eclipse and occultation mean roughly the same thing but are more generally used if the appearance of the nearer body that is blocking the view is nearly the same size or larger than that of the body blocked. However some specific situations have conventions regarding which term or terms are used. Planets transiting in front of stars are termed transiting planets, such as Venus transiting across the Sun or an extra-solar planet crossing in front of its own star. Transits (and eclipses and occultations) offer opportunities for useful measurement and study: occultations of astronomical objects behind the Moon can be used to refine position information and transits of Jupiter and Saturn by their moons have yielded useful data about both the moon and its host planet. The transit (e.g., by an exoplanet) is sometimes referred to as the primary eclipse, if the secondary eclipse is also under discussion.

The transit method is one method of detecting exoplanets and binary stars, through detection of the magnitude variation of stars due to periodic transits. Transits are also useful for follow-up studies of exoplanets discovered by other means, particularly to determine its radius relative to its host star, to help estimate the planet's density.


The word transit is also used more generally in astronomy, for an astronomical body crossing something. One example is a body crossing the field of view of an instrument such as a telescope. Another example is an astronomical body (e.g., the Sun or Moon) crossing the celestial meridian, the meridian line of the celestial sphere that (locally) happens to be directly overhead, through the zenith. A transit telescope or a meridian circle is an astronomical instrument designed to observe and record such an occurrence, often timing the moment of transit as a means to determine the body's right ascension.


(astronomy,event type,transient type)
Further reading:
https://en.wikipedia.org/wiki/Astronomical_transit
https://exoplanets.nasa.gov/faq/31/whats-a-transit/
https://astro4edu.org/resources/glossary/term/367/
https://www.esa.int/ESA_Multimedia/Videos/2019/11/What_is_a_transit
https://astronomy.swin.edu.au/cosmos/m/Meridian+Transit

Referenced by pages:
55 Cancri e (55 Cnc e)
ARIEL
batman
brown dwarf (BD)
cadence
CHEOPS
COROT
CUTE
data folding
differential spectroscopy
double transit
eclipse mapping
Evryscope
ExoFOP
exoplanet eclipse light curve
exosatellite
extra-solar planet
GJ 1214 b
HAT-P-7b
HD 189733 b
HD 209458 b
HD 80606 b
helium 1083 nm line
isochronal fitting
K2
light curve
Lowell Discovery Telescope (LDT)
Lupus Transit Survey
magma ocean
mass function
meridian circle
natural astronomical telescopes
NGTS
occultation
OGLE
phase angle
phase curve
PLATO
radial velocity (RV)
radial velocity method
Rossiter-McLaughlin effect (RM effect)
Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS)
secondary eclipse
signal-to-noise ratio (SNR)
spectroscopy
sunspot
super-Earth
time-domain astronomy
Trans-Atlantic Exoplanet Survey (TrES)
transient (AT)
transient astronomy
transit method
transit spectroscopy
transit telescope
transit timing variations (TTV)
Transiting Exoplanet Survey Satellite (TESS)
transiting planet
TRAPPIST
WASP-12b
WASP-33b
WASP-43b
WASP-67b
water-ice planet
WFCAM Transit Survey (WTS)
XO Project

Index