NGC 205 SySt-2

SUSPECTED NGC 205  

Equatorial coordinates
α =  10.033330 | 00 40 08.000000
δ =  41.756720 | +41 45 24.200000
 
Constellation Andromeda
Symbiotic IR Type  
Spectral Type K5-M2
Magnitude range (V)  
Outbursts No

Identifiers

NGC 205 SySt-2 GSC TYC WRAY
SIMBAD [MMD2006] 2647 HIP SAO Hen
BD – IRAS  GAIA DR2  ESO
HD 2MASS  WISE  AAVSO

Position

Right ascension (°) 10.033330ref  Parallax (mas) Reddening E(B-V) (mag) 0.062 ± 0.005ref
Declination (°) 41.756720ref  Distance (kpc) 824.00 ± 27.00ref    
Galactic longitude (°) 120.673020ref  Proper motion in α (mas/yr)    
Galactic latitude (°) -21.065440ref  Proper motion in δ (mas/yr)    

Observations

U (mag)   X-Ray   Flickering  
B (mag)   X-Ray type   Outbursts No
V (mag) 24.85ref  IUE No Type  
R (mag)   IRAS flux at 12 μm (Jy)   IPmax (eV) 54.9ref 
I (mag)   IRAS flux at 25 μm (Jy)   OVI lines Noref 
G (mag)   IRAS flux at 60 μm (Jy)      
J (mag)   IRAS flux at 100 μm (Jy)      
H (mag)   WISE W1 (mag)      
K (mag)   WISE W2 (mag)      
L (mag)   WISE W3 (mag)      
    WISE W4 (mag)      
    Radio      
    Radio flux (mJy)      

Orbit

Orbital period (days)   γ velocity (km/h)   Size of giant’s orbit (AU)  
Eccentricity   RV of giant (km/h)   Separation (AU)  
Inclination (°)   Inferior conj. of giant (JD)   Mass function  
Ephemeris type       Mass ratio  
Ephemeris T(JD)          

Cool component

Spectral type K5-M2ref  Mass (M)   Pulsation  
Eff. temperature (K)   Radius (R)   Type  
IR type   Luminosity (L)   Pulsation period (days)  
Metallicity [Fe/H]       Ephemeris type  
        Ephemeris T(JD)  

Hot component

Type/Spectra   Mass (M)   Spin period (min)  
Eff. temperature (K) >340000ref  Radius (R)   Accretion disk  
Lower limit (K)   Luminosity (L)      
Upper limit (K)          

Links

SIMBAD     CDS Portal


Notes

NGC 205 SySt-2 has an extremely intense He II 4686 Å emission line, the effective temperature of the star that ionizes the gas should be tremendously high. According to Gonçalves et al. (2015), it is puzzling the fact that higher ionization forbidden lines are not detected in its spectrum. If confirmed as a true symbiotic binary, NGC 205 SySt-2 will be one of a few symbiotics that shows the Ne VII Raman scattering line at 4881 Å.


References

  • Gonçalves, D. R., Magrini, L., de la Rosa, I. G., et al., 2015, MNRAS, 447, 93, 2015MNRAS.447..993G

Last updated: Jan 12, 2019 @ 4:29 pm