NASA’s Hubble Space Telescope photographed comet 46P/Wirtanen on December 13, when the comet was 7.4 million miles (12 million kilometers) from Earth. In the image, the comet’s nucleus is hidden in the center of a fuzzy glow from the comet’s coma. The coma is a cloud of gas and dust that the comet has ejected during its pass through the inner solar system due to heating from the Sun.
To make this composite image, the color blue was applied to high-resolution grayscale exposures acquired from the spacecraft's WFC3 instrument.
The inner part of a comet’s coma is normally not accessible from Earth. The close fly-by of comet 46P/Wirtanen allowed astronomers to study it in detail. They combined the unique capabilities of Hubble, NASA’s Chandra X-ray Observatory, and the Neil Gehrels-Swift observatory to study how gases are released from the nucleus, what the comet’s ices are composed of, and how gas in the coma is chemically altered by sunlight and solar radiation.
Comet 46P/Wirtanen made its closest approach to Earth on December 16, when it passed just over 7 million miles (11 million kilometers) from our planet, about 30 times farther away than the Moon. Although it is the brightest comet of 2018, 46P/Wirtanen is only barely visible to the unaided eye. It is best viewed through binoculars or a telescope. Backyard observers can currently find the comet within the constellation Taurus, between the Pleiades and Hyades star clusters.
Comet 46P/Wirtanen orbits the Sun once every 5.4 years, much quicker than the 75-year orbit of the more famous Comet Halley. Most of its passes through the inner solar system are much farther from Earth, making this year’s display particularly notable.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
Credits
NASA, ESA, and D. Bodewits (Auburn University) and J.-Y. Li (Planetary Science Institute)| About The Object | |
|---|---|
| Object Name | Comet Wirtanen |
| Object Description | Comet |
| R.A. Position | 03:35:19.788 |
| Dec. Position | +10:51:46.36 |
| Constellation | Taurus |
| Distance | About 7 million miles (11.5 million km) |
| Dimensions | Image is about 1500 miles across (2,500 km) |
| About The Data | |
| Data Description | The HST observations include those from program (D. Bodewits) |
| Instrument | WFC3/UVIS |
| Exposure Dates | 13 Dec 2018 |
| Filters | F689M |
| About The Image | |
| Color Info | These images are a composite of separate exposures acquired by the WFC3 instrument on the Hubble Space Telescope. The color results from assigning the color blue to a monochromatic (grayscale) image. |
| Compass Image |  |
| 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. |
