Electronic Telegram No. 5445
Central Bureau for Astronomical Telegrams
Mailing address: Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET C/2023 A3 (TSUCHINSHAN-ATLAS)
Further to CBET 5404, J. N. Marcus clarifies and expands on his work
mentioned therein: "The coma light-scattering model (Marcus 2007a, ICQ 29,
39; Marcus 2007b, ICQ 29, 119; URL http://www.icq.eps.harvard.edu/publ.html)
predicts strong forward-scattering enhancement of the brightness of comet
C/2023 A3 around the time of minimum scattering angle (7.0 deg) on Oct. 9.4
UT. Based on an assumed coma dust-to-gas light ratio of 10 for a 'dusty'
comet (based on the tail morphology and low C_2 relative to dust-production
rates reported earlier by D. Schleicher), the modeled brightness
increase in visual magnitude, relative to that viewed from (normalized to) a
90-degree scattering angle, is as follows for the listed dates and
corresponding scattering angles: 2024 Sept. 29.0 UT (79.5 deg, -0.3 mag);
Oct. 2.0 (58.7, -1.1); 5.0 (36.7, -2.5); 6.0 (29.1, -3.2); 7.0 (21.4, -4.1);
8.0 (13.9, -5.3); 9.0 (7.9, -6.7); 9.4 (7.0, -6.9); 10.0 (8.5, -6.5); 11.0
(15.1, -5.1); 12.0 (23.0, -3.9); 13.0 (31.1, -3.0); 14.0 (39.1, -2.3); 15.0
(46.8, -1.7); 18.0 (67.1, -0.7); and 21.0 (83.1, -0.2)." If a current
baseline set of total-visual-magnitude parameters of H = 6.0 and 2.5n = 8
is maintained to perihelion and beyond, Marcus predicts that the comet's
brightness could exceed mag 0 during Oct. 5-13, mag -2 during Oct. 7-11,
and mag -3 during Oct. 8-10, peaking around Oct. 9.4 at possibly brighter
than mag -4.
Recent digital-camera total magnitudes and coma diameters for C/2023 A3
reported by K. Yoshimoto, Yamaguchi, Japan, using a 135-mm f/3.5 lens + CMOS
camera remotely at "Deep Sky Chile": July 21.99 UT, 9.4, 3'.0; Aug. 9.00,
8.7, 2'.6. Selected visual total-magnitude and coma-diameter estimates:
July 24.90, 9.3, 4' (V. Gonano, Udine, Italy, 20x80 binoculars); 25.91, 9.5,
3' (J. G. de S. Aguiar, Campinas, Brazil, 0.27-m reflector); Aug. 10.90, 8.6,
3' (Aguiar).
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2024 CBAT
2024 September 10 (CBET 5445) Daniel W. E. Green
http://www.cbat.eps.harvard.edu/iau/cbe ... 005445.txt
COMET C/2023 A3 (TSUCHINSHAN-ATLAS)
Re: COMET C/2023 A3 (TSUCHINSHAN-ATLAS)
A recently discovered Comet C/2023 A3, also known as Tsuchinshan, was discovered in January 2023 at the Purple Mountain Observatory in China. It was later confirmed in February by the ATLAS robotic search telescope.
Comet C/2023 A3 is expected to give us a good show in September at dawn and in October at dusk.
Chart for 14 October 2024 onwards
The comet has a good prospect for the dawn, and along with a unique daytime appearance.
Comet Tsuchinshan-ATLAS was first visible only from southern hemisphere latitudes, but it started to climb into the dawn sky in mid-September after spending most of August and early September hidden behind the Sun.
https://www.facebook.com/hazarry/posts/ ... embed_post
When viewed from mid-northern latitudes, it will have traveled far enough north by the last week of September to appear in the dawn sky while positioned in the constellation Sextans.
Table below shows daily rise and set times, celestial positions and useful parameters for Comet C/2023 A3 in October and November from Brunei Darussalam.
Comet C/2023 A3 is expected to give us a good show in September at dawn and in October at dusk.
Chart for 14 October 2024 onwards
- Comet_C2023A3_chart.jpg (39.74 KiB) Viewed 125 times
Comet Tsuchinshan-ATLAS was first visible only from southern hemisphere latitudes, but it started to climb into the dawn sky in mid-September after spending most of August and early September hidden behind the Sun.
- 20240928_comet.png (508.9 KiB) Viewed 119 times
When viewed from mid-northern latitudes, it will have traveled far enough north by the last week of September to appear in the dawn sky while positioned in the constellation Sextans.
Table below shows daily rise and set times, celestial positions and useful parameters for Comet C/2023 A3 in October and November from Brunei Darussalam.
- Comet_C2023A3_ephemerides.jpg (1.1 MiB) Viewed 111 times
Last edited by hazarry on Wed Oct 09, 2024 12:27 pm, edited 1 time in total.
Re: COMET C/2023 A3 (TSUCHINSHAN-ATLAS)
Comet Tsuchinshan-ATLAS flyby the Sun today (October 08, 2024) and heading closest to Earth
Its first appearance in SOHO LASCO C3 field of view (https://soho.nascom.nasa.gov) was captured today, October 07, 2024 at 15:06 UTC.
Comet Tsuchinshan-ATLAS will soon move into the evening sky.
Its first appearance in SOHO LASCO C3 field of view (https://soho.nascom.nasa.gov) was captured today, October 07, 2024 at 15:06 UTC.
- 20241008_soho3_c2023a3.gif (3.11 MiB) Viewed 68 times
20241008_soho3_c2023a3.mp4- (8.57 MiB) Downloaded 3 times
Re: COMET C/2023 A3 (TSUCHINSHAN-ATLAS)
- CometC2023A3T_ATLAS_info.jpg (148.31 KiB) Viewed 54 times