A new image of the sunward plunging Comet ISON suggests that the comet is intact despite some predictions that the fragile icy nucleus might disintegrate as the Sun warms it. The comet will pass closest to the Sun on November 28.
In this NASA Hubble Space Telescope image taken on October 9, the comet's solid nucleus is unresolved because it is so small. If the nucleus broke apart then Hubble would have likely seen evidence for multiple fragments.
Moreover, the coma or head surrounding the comet's nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along. A polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.
This color composite image was assembled using two filters. The comet's coma appears cyan, a greenish-blue color due to gas, while the tail is reddish due to dust streaming off the nucleus. The tail forms as dust particles are pushed away from the nucleus by the pressure of sunlight. The comet was inside Mars' orbit and 177 million miles from Earth when photographed. Comet ISON is predicted to make its closest approach to Earth on December 26, at a distance of 39.9 million miles.
Credits
NASA, ESA, and the Hubble Heritage Team (STScI/AURA)| About The Object | |
|---|---|
| Object Name | Comet ISON |
| Object Description | Comet |
| Distance | At the time of the Hubble observations on October 9, 2013, the comet was 1.49 astronomical units (139 million miles) from the Sun. The comet was 1.91 astronomical units (177 million miles) from Earth. |
| About The Data | |
| Data Description | The image was created from Hubble data from proposal by the Hubble Heritage Team, PI: Z. Levay, M. Mutchler, C. Christian, L. Frattare, W. Januszewski, M. Livio, J. Mack, and J. Sokol (STScI/AURA), and K. Noll (NASA/GSFC). High-level science products for these data are available from the MAST archive at . |
| Instrument | HST>WFC3/UVIS |
| Exposure Dates | October 9, 2013, Exposure Time: 29 minutes |
| Filters | F438W (B) and F775W (i') |
| About The Image | |
| Color Info | This image is a composite of separate exposures acquired by the WFC3/UVIS instrument. Several filters were used to sample various wavelengths. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue/green: F438W (B) and Orange: F775W (i') |
| 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. |
