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Cepheid Variable Star P42 in NGC 5468

A horizontal, two-panel image of a pixelated star field.

At the center of these side-by-side images is a special class of star used as a milepost marker for measuring the universe’s rate of expansion – a Cepheid variable star. The two images are very pixelated because they are a very zoomed-in view of a distant galaxy. Each of the pixels represents one or more stars. The image from the James Webb Space Telescope is significantly sharper at near-infrared wavelengths than Hubble (which is primarily a visible-ultraviolet light telescope). By reducing the clutter with Webb’s crisper vision, the Cepheid stands out more clearly, eliminating any potential confusion. Webb was used to look at a sample of Cepheids and confirmed the accuracy of the previous Hubble observations that are fundamental to precisely measuring the universe’s expansion rate and age.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    14:06:35.01
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    -05:27:15.72
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Virgo
  • Distance
    DistanceThe 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.
    About 130 million light-years

About the Data

  • Data Description
    Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
    Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.

    This image was created with Webb and Hubble data from proposals: 1685 and 11570 (A. Riess). Image processing: Alyssa Pagan (STScI).

  • Instrument
    InstrumentThe science instrument used to produce the data.
    Hubble>WFC3/IRWebb>NIRCam
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    Hubble> 28 December 2017- 25 March 2018Webb> 28 June 2023, 15 July 2023
  • Filters
    FiltersThe camera filters that were used in the science observations.
    Hubble> F160WWebb> F150W
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Cephied P42
  • Object Description
    Object DescriptionThe type of astronomical object.
    Cephied in NGC 5468
  • Release Date
    March 11, 2024
  • Science Release
    NASA’s Webb, Hubble Telescopes Affirm Universe’s Expansion Rate, Puzzle Persists
    Read the release
  • Credits
    NASA, ESA, CSA, STScI, Adam Riess (JHU, STScI)

Downloads

  • Full Res (For Print), 1298 × 726
    tif (2.5 MB)
  • Full Res (For Display), 1298 × 726
    png (1.06 MB)
A horizontal, two-panel image of a pixelated star field.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

The images are separate exposures acquired by the NIRCam instrument on the James Webb Space Telescope (left) and the WFC3/IR instrument on the Hubble Space Telescope (right).

Related Images & Videos

A face-on spiral galaxy with four spiral arms that curve outward in a counterclockwise direction. The spiral arms are filled with young, blue stars and peppered with purplish star-forming regions that appear as small blobs. The middle of the galaxy is much brighter and more yellowish, and has a distinct narrow linear bar angled from 11 o’clock to 5 o’clock. Dozens of red background galaxies are scattered across the image. The background of space is black.

NGC 5468 (Webb NIRCam + Hubble WFC3)

This image of NGC 5468, a galaxy located about 130 million light-years from Earth, combines data from the Hubble and James Webb space telescopes. This is the farthest galaxy in which Hubble has identified Cepheid variable stars. These are important milepost markers for measuring...

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Details

Last Updated
Mar 10, 2025
Contact
Media

Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov

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