Glossary

Airmass - A measure of the amount of air along a line of site when observing a star from below Earth’s atmosphere. It matters because the atmosphere scatters and absorbs light. The thicker the atmosphere through which starlight passes, the more the light can be distorted.

Astrophysicist - A person who studies objects that are visible in the night sky

Biases - Very short exposure pictures taken with no light falling on the image sensor, used for calibrating images

BJD - Barycentric Julian Date - the day of the year, corrected for differences in Earth’s position with respect to the barycenter of the solar system, used in astronomy to define a very precise date and time

Citizen scientist - A person who volunteers to participate in a scientific activity such as collecting or analyzing data, participating in a group project to learn more than individual scientists could learn on their own

Darks - Pictures taken through a telescope with the lens cap on, to filter out noise from the camera sensor

Data - Information collected by a scientific instrument, in our case, a telescope

Egress - The point during an exoplanet transit at which the exoplanet transit ends, once the exoplanet finishes passing in front of the disc of its host star

Ephemeris - (plural: ephemerides) - A table or data file of the calculated positions of an object in the sky at regular intervals throughout a time period

Exoplanet - A planet that is beyond our Solar System

EXOTIC - EXOplanet Transit Interpretation Code - Software that detects exoplanets by measuring the dimming of a star as an orbiting exoplanet passes in front of it.

Filters - Optical filters cover a telescope’s lens or mirror to make it easier to measure the number of photons of selected wavelengths of light. They cut out unwanted colors or wavelengths of light, enhancing details and improving contrast.

FITS or Flexible Image Transport System - FITS is the most commonly used digital file format in astronomy. The FITS standard was designed specifically for astronomical data, and includes provisions such as describing photometric and spatial calibration information, together with image origin metadata.

Flats - Fully illuminated images that have uniform lighting across the whole frame. Used for calibrating a telescope and removing dust spots on a camera sensor.

Host star - The star an exoplanet orbits around

Ingress - The point during an exoplanet transit when the whole planet has moved onto the stellar disc

Hot Jupiters - gas giant planets that orbit very close to their host star, giving the planet a high temperature

Light curve - A graph showing the change in brightness of a star over time as an exoplanet passes in front of it, as seen from the observer or telescope

Observations - Watching something carefully to gain information about it, in this case, looking at the night sky with a telescope and taking a photograph every few minutes, then using a computer to compare the brightness of a star before, during, and after an exoplanet passes in front of it

Orbital Period - The length of time it takes for a planet to orbit its star. The length of the exoplanet’s year, or the time between transits.

Planet composition - What a planet is made of (rocks, minerals, metals and/or gasses)

Relative flux - The brightness of a star compared to another star

Super-Earths - Rocky planets that are more massive than Earth but smaller than Uranus

Telescope - Optical equipment consisting of lenses and/or mirrors used for observing distant objects such as stars and planets

Telescope Mount - The part of the telescope system that controls the direction in the sky where the telescope is pointing

Transit - When an object passes in front of another object

Transit Depth - The ratio of the area of the planet to the area of the star, related to the change in brightness of the star as the exoplanet passes in front of it. A transit depth of 0.2 means 20% of the star’s brightness is being blocked. Used for calculating the size of the exoplanet, if the size of the star is already known.

Vmag - Visual magnitude or apparent relative brightness of a star

Types of Exoplanets

Exoplanet News