C/2002 T7 (LINEAR)
Hyperbolic comet discovered by LINEAR, brightened to magnitude 2.2.
C/2002 T7 (LINEAR) is a hyperbolic comet first spotted in 2002 by the LINEAR survey. Its brightness peaked at magnitude 2.2 in 2004.
The LINEAR project reported the object on 14 October 2002, when it shone at magnitude 17.5. Several observatories tracked it later that month, and on 29 October the International Astronomical Union confirmed it as a comet. Pre-discovery images from LINEAR dated 12 October were later found. At discovery, the comet was 6.9 AU from the Sun. It is considered a dynamically new visitor from the Oort Cloud, making its first journey closer to the Sun than Jupiter.
The comet grew brighter until mid-February 2004, then held at magnitude 7 until early March, when it entered twilight and became hard to observe. Its minimum solar elongation of 9° occurred in late March. It reappeared in twilight on 9 April at magnitude 4.6. Perihelion came on 23 April, but the comet continued to brighten as it neared Earth. Its closest approach was on 19 May 2004, with an estimated magnitude between 2.5 and 3. At that time, it shared the sky with the similarly bright comet C/2001 Q4 (NEAT).
On 30 April 2004, the Rosetta spacecraft’s remote-sensing instruments imaged and studied the comet from about 95 million kilometres away. Measurements of its coma and tail spanned ultraviolet to microwave wavelengths, and water molecules were successfully detected.
Quick Facts
- Discovery Ref
- IAUC_8003
- Discoverer
- LINEAR
- Discovery Date
- 14 October 2002
- Designations
- CK02T070MPEC-2002-U43
- Orbit Ref
- jpl
- Epoch
- 16 November 2003 (JD 2452959.5)
- Observation Arc
- 1,242 days
- Earliest Precovery Date
- 12 October 2002
- Obs
- 4,397
- Perihelion
- 0.614 AU
- Eccentricity
- 1.000487
- Inclination
- 160.58°
Facts from the source article.
Lore & Background
The LINEAR project announced the discovery of C/2002 T7 on 14 October 2002, when it had a magnitude of 17.5. Follow-up observations were obtained by several observatories before the end of the month, and on October 29 the International Astronomical Union announced it to be a comet. Prediscovery images from October 12 were later found. At discovery, the comet was 6.9 AU from the Sun and is considered a dynamically new object from the Oort Cloud, marking its first approach closer to the Sun than Jupiter.
The comet brightened until mid-February 2004, then stayed at magnitude 7 until early March, when it entered twilight and became difficult to observe. It passed a minimum solar elongation of 9° in late March. It was observed again on April 9 in twilight at magnitude 4.6. Perihelion occurred on April 23, but the comet continued to brighten as it approached Earth. Its closest approach was on 19 May 2004, with an estimated magnitude of 2.5 to 3. At that time, it was visible in the sky alongside the equally bright comet C/2001 Q4 (NEAT).
On 30 April 2004, the comet was imaged and studied using remote-sensing devices on the Rosetta spacecraft from a distance of about 95 million kilometres. The coma and tail were measured in wavelengths from ultraviolet to microwave, and the presence of water molecules around the comet was successfully identified.
Reader's Guide
C/2002 T7 (LINEAR) holds significance as a dynamically new comet from the Oort Cloud, making its first passage inside Jupiter's orbit. Its peak brightness of magnitude 2.2 in 2004 made it a notable naked-eye object, and it was observed simultaneously with another bright comet, C/2001 Q4 (NEAT), offering a rare dual-comet display. The comet's legacy is further enhanced by its study by the Rosetta spacecraft on 30 April 2004, which measured its coma and tail across ultraviolet to microwave wavelengths from 95 million kilometres away, successfully identifying water molecules. This early remote sensing contributed to understanding cometary composition before Rosetta's later rendezvous with comet 67P/Churyumov–Gerasimenko. The comet's hyperbolic orbit and discovery by the LINEAR project underscore the role of automated surveys in finding new comets.
Did You Know?
- The comet was discovered by the LINEAR project on 14 October 2002 at magnitude 17.5.
- It brightened to a magnitude of 2.2 in 2004.
- On 30 April 2004, the Rosetta spacecraft studied the comet from 95 million kilometres away.
- The comet was visible in the sky alongside comet C/2001 Q4 (NEAT) in May 2004.
Frequently Asked Questions
What is C/2002 T7 (LINEAR)?
It is a hyperbolic comet first flagged by the LINEAR automated survey in October 2002, when it glowed at a faint magnitude 17.5 while sitting 6.9 AU from the Sun. The IAU formally recognized it as a comet on 29 October 2002 after follow-up tracking from several observatories.
How bright did C/2002 T7 (LINEAR) get at its peak?
The comet brightened to a naked-eye magnitude of 2.2 during its 2004 apparition, with perihelion arriving on 23 April 2004. Its closest approach to Earth came a few weeks later, on 19 May 2004.
Where does C/2002 T7 (LINEAR) originate from?
It is classified as a dynamically new visitor from the Oort Cloud, meaning this 2002–2004 passage was its very first trip inside Jupiter's orbit. Its hyperbolic trajectory tells us it is on a one-way escape and will not return.
When and how was C/2002 T7 (LINEAR) discovered?
LINEAR reported the object on 14 October 2002 at magnitude 17.5, and pre-discovery frames from 12 October were later pulled from the survey archive. The IAU confirmed its cometary nature on 29 October after additional observations.
Why is C/2002 T7 (LINEAR) considered special among named comets?
As a dynamically new Oort Cloud comet on a hyperbolic path, it made a single, unrepeatable pass through the inner solar system. Its bright 2004 peak at magnitude 2.2 turned that one-time visit into a memorable naked-eye event for skywatchers.
More in Named Comets, Part 2 1-24
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