19 Draconis
 19 Draconis in optical light | |
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 16h56m01.68925s[1] |
| Declination | +65° 08′ 05.2631″[1] |
| Apparent magnitude(V) | 4.89[2] |
| Characteristics | |
| Spectral type | F8V[3] |
| U−Bcolor index | -0.03[2] |
| B−Vcolor index | +0.485[2] |
| Astrometry | |
| Radial velocity(Rv) | −21.00 ± 0.8[4]km/s |
| Proper motion(μ) | RA:237.79[1]mas/yr Dec.:50.84[1]mas/yr |
| Parallax(π) | 65.54 ± 0.33mas[1] |
| Distance | 49.8 ± 0.3ly (15.26 ± 0.08pc) |
| Absolute magnitude(MV) | 3.98[5] |
| Orbit[5] | |
| Period(P) | 52.1089 ± 0.0001 d |
| Semi-major axis(a) | 20.0 mas |
| Eccentricity(e) | 0.2221 ± 0.0002 |
| Inclination(i) | 90.5 ± 2.2° |
| Longitude of the node(Ω) | 23.5 ± 2.0° |
| Periastronepoch(T) | JD 2453427.880 ± 0.007 |
| Argument of periastron(ω) (secondary) | 338.46 ± 0.05° |
| Semi-amplitude(K1) (primary) | 17.465 ± 0.004 km/s |
| Details[5] | |
| 19 Dra A | |
| Mass | 1.04M☉ |
| Radius | 1.2R☉ |
| Luminosity | 2.02L☉ |
| Temperature | 6298 ± 80K |
| Metallicity | Z = 0.013 ± 0.004 |
| Age | 4.7Gyr |
| 19 Dra B | |
| Mass | 0.37M☉ |
| Radius | 0.3R☉ |
| Luminosity | 0.02L☉ |
| Temperature | ~3963[note 1]K |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
19 Draconis,also known ash Draconis,is astarsystem in theconstellationDraco.It is visible to the naked eye as a faint, yellow-white hued star with anapparent visual magnitudeof 4.89.[2]Based on itsparallax,the system is located about 49.8light-years(15.26parsecs) away.[1]It is moving closer to the Earth with a heliocentricradial velocityof −21 km/s.[4]
This is abinary starsystem with anorbital periodof 52.1 days and aneccentricityof 0.22. Only the primary star can be directly detected, viaDoppler shiftsorperturbationsaround the system's barycenter. Using spectroscopy and astrometry, the nature of the secondary star can be inferred. The primary star is anF-type main-sequence starwith astellar classificationof F8V,[3]4% more massive than theSun.Its surface temperature is about 6,298K,and it emits just over twice the amount of energy that the Sun does. The secondary is only 37% as massive as theSun,and its luminosity is only 2% that of the Sun. The system is about 4.7 billion years old.[5]
References
[edit]- ^abcdefvan Leeuwen, F.; et al. (2007)."Validation of the new Hipparcos reduction".Astronomy and Astrophysics.474(2): 653–664.arXiv:0708.1752.Bibcode:2007A&A...474..653V.doi:10.1051/0004-6361:20078357.S2CID18759600.
- ^abcdMermilliod, J.-C. (1986)."Compilation of Eggen's UBV data, transformed to UBV (unpublished)".Catalogue of Eggen's UBV Data.Bibcode:1986EgUBV........0M.
- ^abAbt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries".The Astrophysical Journal Supplement.180(1): 117–18.Bibcode:2009ApJS..180..117A.doi:10.1088/0067-0049/180/1/117.S2CID122811461.
- ^abGontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system".Astronomy Letters.32(11): 759–771.arXiv:1606.08053.Bibcode:2006AstL...32..759G.doi:10.1134/S1063773706110065.S2CID119231169.
- ^abcdWang, Xiaoli; Ren, Shulin; Fu, Yanning (2015)."Self-Consistent Orbits and Physical Properties for Eight Single-Lined Spectroscopic Binaries".The Astronomical Journal.150(4): 110.Bibcode:2015AJ....150..110W.doi:10.1088/0004-6256/150/4/110.
Notes
[edit]- ^FromL= 4πR2σTeff4,rearranging to makeTeff= (L/ 4πR2σ)1/4.WhereLis the luminosity,Ris the radius,Teffis the effective surface temperature andσis theStefan–Boltzmann constant.
