21287+7034 LAB 6 Aa,Ab
21h 28m 39.58s +70° 33' 38.5" P.A. 226.00 sep 0.2 mag 3.20,6.60 Sp B2III dist. 210.08 pc (685.28 l.y.)
| Coord 2000 |
21287+7034 |
|
Discov num |
LAB 6 |
|
Comp |
Aa,Ab |
|
Coord arcsec 2000 |
21 28 39.58 +70 33 38.5 |
|
| Date first |
1971 |
|
Date last |
2007 |
|
Obs |
85 |
|
| Pa first |
47 |
|
Pa last |
226 |
|
P.A. Now (θ) |
46.3° |
|
| Sep first |
0.3 |
|
Sep last |
0.172 |
|
Sep. Now (ρ) |
0.299" |
|
| Mag pri |
3.20 |
|
Mag sec |
6.60 |
|
delta mag (ΔM) |
3.4 |
|
Spectral class |
B2III (blue-white) |
|
| Pri motion ra |
+013 |
|
Sec motion ra |
|
|
| Pri motion dec |
+008 |
|
Sec motion dec |
|
|
| Notes |
N
O
(See Notes, Orbital solution) |
|
This double is physical.
21287+7034 SYSTEM COMPONENTS
| Show |
name |
SAO |
coord |
wds_name |
last |
obs |
pa |
sep |
mag1 |
mag2 |
d_mag |
orb |
current |
| Show |
|
10057 |
21 28 40 +70 33 38 |
LAB 6 Aa,Ab |
2007 |
85 |
226 |
0.2 |
3.20 |
6.60 |
3.40 |
Y |
<=== |
| Show |
Alfirk |
10057 |
21 28 40 +70 33 38 |
STF 2806 AB |
2020 |
104 |
250 |
13.6 |
3.17 |
8.63 |
5.46 |
|
|
Triple system
2 estimated visually detectable stars in this system
OTHER CATALOGS AND DESIGNATIONS
| Common name |
Alfirk |
|
Constellation |
Cepheus |
|
SAO |
10057 |
|
HIP |
106032 |
|
| Tycho2 |
4465-02643-1 |
|
Gaia DR2 |
2272185759992826624 |
|
HD |
205021 |
|
HR |
8238 |
|
| GC |
30118 |
|
ADS |
15032 |
|
BD |
BD+69 1173 |
|
Bayer |
Beta Cephei |
|
| Bayer name |
Bet Cep |
|
Flamsteed |
8 Cephei |
|
Flamsteed name |
8 Cep |
|
FK5 |
809 |
|
| Distance |
210.08 |
|
Distance ly |
685.28 |
|
Bayer greek |
β Cep |
|
ORBITAL ELEMENTS
| Period (P) | 83y | |
Periastron (T) | 1997.99y | |
Semi-major axis (a) | 0.195a | |
| Eccentricity (e) | 0.732 | |
Inclination (i) | 87.3° | |
Longitude of periastron (ω) | 194.6° | |
| Node (Ω) | 46.4° | |
Notes | n | |
Reference | Ana2006 | |
| Equinox | 2000 | |
Last observation | 1998 | |
Grade | 3 | (1=Definitive, 9=Indet.) |
| label |
theta |
rho |
| 2000 |
243.9 |
0.011 |
| 2001 |
31.7 |
0.016 |
| 2002 |
40.1 |
0.040 |
| 2003 |
42.2 |
0.063 |
| 2004 |
43.2 |
0.085 |
| 2005 |
43.8 |
0.104 |
| 2006 |
44.2 |
0.123 |
| 2007 |
44.5 |
0.140 |
| 2008 |
44.7 |
0.156 |
| 2009 |
44.9 |
0.171 |
| 2010 |
45.1 |
0.185 |
| 2011 |
45.2 |
0.197 |
| 2012 |
45.4 |
0.210 |
| 2013 |
45.5 |
0.221 |
| 2014 |
45.6 |
0.231 |
| 2015 |
45.7 |
0.241 |
| 2016 |
45.8 |
0.251 |
| 2017 |
45.9 |
0.259 |
| 2018 |
45.9 |
0.267 |
| 2019 |
46.0 |
0.275 |
| 2020 |
46.1 |
0.281 |
| 2021 |
46.1 |
0.288 |
| 2022 |
46.2 |
0.294 |
| 2023 |
46.3 |
0.299 |
| 2024 |
46.3 |
0.304 |
| 2025 |
46.4 |
0.308 |
| 2026 |
46.4 |
0.312 |
| 2027 |
46.5 |
0.316 |
| 2028 |
46.5 |
0.319 |
| 2029 |
46.6 |
0.322 |
| 2030 |
46.6 |
0.324 |
|
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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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