This illustration shows the rhythmic rise and fall of starlight from the Cepheid variable star V1 over a seven-month period.
Cepheid variables are pulsating stars that brighten and fade in a predictable pattern. The illustrated graph shows that V1 completes a pulsation cycle every 31.4 days. The red dots on the graph represent observations by the American Association of Variable Star Observers (AAVSO), who partnered with the Space Telescope Science Institute's Hubble Heritage Project to study the star. The four stars on the graph denote observations made by the Hubble Space Telescope's Wide Field Camera 3.
Ten amateur astronomers from around the world made 214 observations of V1 between July 2010 and December 2010, obtaining four pulsation cycles. The AAVSO study allowed the Hubble Heritage team to target Hubble observations that would capture the star at its brightest and dimmest phases.
Credits
Illustration: NASA, ESA, and Z. Levay (STScI);Science: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and the American Association of Variable Star Observers;
Acknowledgment: T. Rector (University of Alaska, Anchorage)
| About The Object | |
|---|---|
| Object Name | M31 |
| R.A. Position | 00h 41m 26.99s |
| Dec. Position | 41° 10' 6.0" |
| 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. |
