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
Other names ALPHIRK
Meaning Raw
 
 
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° Notesn ReferenceAna2006
Equinox2000 Last observation1998 Grade3(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


 
grafico orbita
Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.



 
 


wds21287%2B7034a.png orbit plot
Measures: green=micrometric, blue=interferometric, purple=photographic