This diagram illustrates the combined power of the Hubble and Webb space telescopes in nailing down precise distances to a special class of variable star that is used in calibrating the expansion rate of the universe. These Cepheid variable stars are seen in crowded star fields. Light contamination from surrounding stars may make the measurement of the brightness of a Cepheid less precise. Webb’s sharper infrared vision allows for a Cepheid target to be more clearly isolated from surrounding stars, as seen in the right side of the diagram. The Webb data confirms the accuracy of 30 years of Hubble observations of Cepheids that were critical in establishing the bottom rung of the cosmic distance ladder for measuring the universe’s expansion rate. At the left, NGC 5584 is seen in a composite image from Webb’s NIRCam (Near-Infrared Camera) and Hubble’s Wide Field Camera 3.
Credits
Science
NASA, ESA, CSA, Adam G. Riess (JHU, STScI)
Illustration
Joyce Kang (STScI)
| About The Object | |
|---|---|
| Object Name | NGC 5584 |
| Object Description | Spiral galaxy, cepheid host galaxy |
| R.A. Position | 14:22:23.76 |
| Dec. Position | 00:23:15.61 |
| Constellation | Virgo |
| Distance | About 72 million light-years (22 million parsecs) |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
