[Left]
Two images of a crowded starfield as seen through a ground-based telescope show the subtle brightening of a star due to the effect of gravitational microlensing, where an invisible but massive foreground object passes in front of the star and amplifies its light. The dark lensing object is estimated to be a six-solar-mass black hole that is drifting alone among the stars.
[Right]
A NASA Hubble Space Telescope image of the same field clearly resolves the lensed star and yields its true brightness. The Hubble observation was needed because the ground-based images do not tell how bright the lensed star actually was before (or after) it was lensed. The star fields where microlensing events are observed are so crowded with stars that the lensed star images are often blended together with images of unlensed stars. But with the Hubble images, astronomers can identify the lensed star and determine its normal brightness. The Hubble images were taken on June 15, 1999.
Credits
[LEFT] – NOAO, Cerro Tololo Inter-American Observatory;[Right] – NASA and Dave Bennett (University of Notre Dame, Indiana)
| About The Object | |
|---|---|
| Object Name | MACHO-96-BLG-5 |
| 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. |
