C/2001 A2 (LINEAR)
Semi-major axis 1,118 AU | | |
Eccentricity | 0.9993 | |
---|---|---|
Orbital period | 37,400 years | |
Inclination | 36.48° | |
295.12° | ||
Argument of periapsis | 295.33° | |
Last perihelion | 24 May 2001 | |
Earth MOID | 0.051 AU | |
Comet total magnitude (M1) | 7 |
C/2001 A2 (LINEAR) is a non-periodic
Observational history
The comet was discovered on 15 January 2001 by the
The comet brightened slowly at on 14 March 2001 its magnitude was estimated to be 13.1.[6] However in late March 2001 the comet experienced an outburst, brightening from about magnitude 10.8 on 28 March to a magnitude of 8 on 30 March.[7] In mid April the comet was estimated to have a magnitude of about 7.5, while on 18 April, it had brightened to a magnitude of 7,[8] and by the end of the month its magnitude was estimated to be about 6.3.[9]
Fragmentation events
Carl W. Hergenrother, Matthew A. Chamberlain, and Y. Chamberlain, of the Lunar and Planetary Laboratory reported the discovery of a double nucleus in images obtained on 30 April 2001. The two nuclei were of equal brightness and separated by 3.5 arcseconds.[9] Zdenek Sekanina calculated that the splitting occurred on Mar. 29.9 ± 1.6 UT, when the outburst was observed.[10]
Images obtained by the 8.2-metre
One more outburst was observed in June, with the comet been reported to have an apparent magnitude of 3.3 on 12 June, but by 18 June it had faded to a magnitude of 4.3, while its coma was reported to be 15 arcminutes across and its tail 4.5 degree long.[15] High resolution imaging of the coma on 16–21 June indicated the presence of more fragments, named D, E, and F, near fragment B. Fragment D was separated on June 3.5 ± 1.8, fragment E on June 9.5 ± 0.7, and fragment F on June 11.3 ± 0.5, and resulted in an outburst.[16] The successive fragmentation events in early June could explain the slow rise of the outburst, which lasted 8 days.[14]
The closest approach to Earth took place on 30 June 2001, at a distance of 0.244 AU (36.5 million km; 22.7 million mi).[2] On July 1 the comet had an estimated magnitude of 4.4–4.5 and its coma was estimated to be 16–20 arcminutes across.[16] On 5 July two tails were observed, each two degrees long, and the magnitude was estimated to be about 5.[17] On more outburst took place in mid July, as the comet was reported to have a magnitude of 4.4 on 13 July, but by the end of the month its magnitude was reported to be about 7.[18] No new fragment was detected after that outburst.[14] Smaller outbursts of amplitude 0.4 and 0.2 mag were observed on July 25.0 and 30.0 respectively.[19]
Scientific results
The
The radio spectrum of the comet in the submillimeter and millimeter was obtained using the
The comet was also observed by the Far Ultraviolet Spectroscopic Explorer on 12 July 2001, during an outburst. In spectrum of the comet were detected for the first time in a comet the C–X and B–X lines of carbon monoxide, OI (1D–1D) at 1152 Å and three hydrogen lines of the Lyman series. The flux of all the lines was decreased by a factor of two within 7.5 hours. The CO emission could be separated into a cold and a hot component, with the cold component being attributed to excitation of CO2.[24]
References
- ^ a b "IAUC 7564: C/2001 A2; 2001J; 2001G". www.cbat.eps.harvard.edu. 16 January 2001. Retrieved 10 March 2023.
- ^ a b "Small-Body Database Lookup: C/2001 A2-B (LINEAR)". ssd.jpl.nasa.gov.
- S2CID 118729804.
- ^ "Brightest comets seen since 1935". www.icq.eps.harvard.edu. Retrieved 26 August 2023.
- ^ "MPEC 2001-B05 : COMET C/2001 A2 (LINEAR)". minorplanetcenter.net. 16 January 2001.
- ^ "IAUC 7600: P/2000 WT_168; C/2001 A2". www.cbat.eps.harvard.edu. 20 March 2001.
- ^ "IAUC 7605: 2001ai; C/2001 A2". www.cbat.eps.harvard.edu. 30 March 2001.
- ^ "IAUC 7611: 2001ay; SGR 1900+14; C/2001 A2". www.cbat.eps.harvard.edu. 19 April 2001.
- ^ a b "IAUC 7616: C/2001 A2; 2001bb". www.cbat.eps.harvard.edu. 1 May 2001.
- ^ a b "IAUC 7630: 2001bq; C/2001 A2". www.cbat.eps.harvard.edu. 22 May 2001.
- ^ "Comet LINEAR Splits Further - Third Nucleus Observed with the VLT". www.eso.org. 18 May 2001. Retrieved 27 August 2023.
- ^ "IAUC 7627: Poss. N IN Aql; C/2001 A2". www.cbat.eps.harvard.edu. 17 May 2001.
- ^ "IAUC 7625: C/2001 J1; C/2001 A2; 2001bf". www.cbat.eps.harvard.edu. 15 May 2001.
- ^ S2CID 122522118.
- ^ "IAUC 7645: 2001cp; 2001ck; 2001cm; C/2001 A2". www.cbat.eps.harvard.edu. 20 June 2001.
- ^ a b "IAUC 7656: C/2001 A2". www.cbat.eps.harvard.edu. 5 July 2001.
- ^ "IAUC 7659: X-RAY TRANSIENTS IN M31; C/2001 A2". www.cbat.eps.harvard.edu. 12 July 2001.
- ^ "IAUC 7676: C/2001 O2; 2001dk; 2001dl; C/2001 A2". www.cbat.eps.harvard.edu. 1 August 2001.
- ^ "IAUC 7679: 2001dm; V1178 Sco; C/2001 A2". www.cbat.eps.harvard.edu. 9 August 2001.
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- S2CID 12938088.
- S2CID 117846683.