20557-6609 HDS 2981 AB (HD 198678)
20h 55m 40.79s -66° 08' 59.7" P.A. 243.00 sep 0.1 mag 8.17,9.00 Sp G3V dist. 101.52 pc (331.16 l.y.)
| Coord 2000 |
20557-6609 |
|
Discov num |
HDS2981 |
|
Comp |
AB |
|
Coord arcsec 2000 |
20 55 40.79 -66 08 59.7 |
|
| Date first |
1991 |
|
Date last |
2021 |
|
Obs |
8 |
|
| Pa first |
31 |
|
Pa last |
242.5 |
|
P.A. Now (θ) |
242.5° |
|
| Sep first |
0.1 |
|
Sep last |
0.076 |
|
Sep. Now (ρ) |
0.076" |
|
| Mag pri |
8.17 |
|
Mag sec |
9.00 |
|
delta mag (ΔM) |
0.83 |
|
Spectral class |
G3V (yellow) |
|
| Pri motion ra |
-002 |
|
Sec motion ra |
|
|
| Pri motion dec |
-005 |
|
Sec motion dec |
|
|
| Notes |
O
(Orbital solution) |
|
This double is physical.
20557-6609 SYSTEM COMPONENTS
| Show |
name |
SAO |
coord |
wds_name |
last |
obs |
pa |
sep |
mag1 |
mag2 |
d_mag |
orb |
current |
| Show |
HD 198678 |
254899 |
20 55 41 -66 08 60 |
HDS 2981 AB |
2021 |
8 |
243 |
0.1 |
8.17 |
9.00 |
0.83 |
Y |
<=== |
| Show |
|
254899 |
20 55 41 -66 08 60 |
HDS 2981 AC |
2021 |
1 |
172 |
1.3 |
8.17 |
14.50 |
6.33 |
|
|
Triple system
3 estimated visually detectable stars in this system
OTHER CATALOGS AND DESIGNATIONS
| Name |
HD 198678 |
|
Constellation |
Pavo |
|
SAO |
254899 |
|
HIP |
103302 |
|
| Tycho2 |
9113-00624-1 |
|
HD |
198678 |
|
CP |
CP-66 3510 |
|
Distance |
101.52 |
|
| Distance ly |
331.16 |
|
SUSPECTED ORBITAL ELEMENTS
| Identifier | 20557-6609 HDS2981 |
| coord_arcsec_2000 | 205540.79-660859.7 |
| Period (P) | 19.32y | |
Periastron (T) | 2023.33y | |
Semi-major axis (a) | 0.099a | |
| Eccentricity (e) | 0.35 | |
Inclination (i) | 156.4° | |
Longitude of periastron (ω) | 191.1° | |
| Node (Ω) | 16.9° | |
Notes | | |
Reference | Tok2021c | |
| Equinox | 2000 | |
Last observation | 2021 | |
Grade | 3 | (1=Definitive, 9=Indet.) |
| label |
theta |
rho |
| 2000 |
301.8 |
0.094 |
| 2001 |
281.6 |
0.083 |
| 2002 |
255.7 |
0.073 |
| 2003 |
223.7 |
0.067 |
| 2004 |
187.1 |
0.064 |
| 2005 |
149.0 |
0.065 |
| 2006 |
114.9 |
0.072 |
| 2007 |
88.5 |
0.083 |
| 2008 |
68.9 |
0.096 |
| 2009 |
53.8 |
0.108 |
| 2010 |
41.6 |
0.118 |
| 2011 |
31.1 |
0.126 |
| 2012 |
21.6 |
0.131 |
| 2013 |
12.6 |
0.133 |
| 2014 |
3.8 |
0.133 |
| 2015 |
354.7 |
0.130 |
| 2016 |
345.1 |
0.125 |
| 2017 |
334.5 |
0.117 |
| 2018 |
322.2 |
0.108 |
| 2019 |
307.3 |
0.097 |
| 2020 |
288.7 |
0.086 |
| 2021 |
264.7 |
0.076 |
| 2022 |
234.6 |
0.069 |
| 2023 |
199.2 |
0.065 |
| 2024 |
161.1 |
0.064 |
| 2025 |
125.1 |
0.069 |
| 2026 |
96.1 |
0.079 |
| 2027 |
74.6 |
0.092 |
| 2028 |
58.3 |
0.104 |
| 2029 |
45.3 |
0.115 |
| 2030 |
34.3 |
0.124 |
|
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Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.
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Measures: green=micrometric, blue=interferometric, purple=photographic |
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