Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Delphinus |
A | |
Right ascension | 20h 30m 17.9623s[1] |
Declination | +10° 53′ 45.335″[1] |
Apparent magnitude (V) | 6.20±0.01[2] |
B | |
Right ascension | 20h 30m 17.9505s[3] |
Declination | +10° 53′ 46.244″[3] |
Apparent magnitude (V) | 8.00±0.01[2] |
Characteristics | |
Spectral type | A1:III shell[4] |
U−B color index | −0.11[5] |
B−V color index | −0.03[5] |
Astrometry | |
Radial velocity (Rv) | −15.5 ± 2[6] km/s |
Absolute magnitude (MV) | −0.69[7] |
A | |
Proper motion (μ) | RA: +19.320 mas/yr[1] Dec.: +4.645 mas/yr[1] |
Parallax (π) | 4.6400 ± 0.0616 mas[1] |
Distance | 703 ± 9 ly (216 ± 3 pc) |
B | |
Proper motion (μ) | RA: +19.545[3] mas/yr Dec.: +4.710[3] mas/yr |
Parallax (π) | 4.1851 ± 0.1421 mas[3] |
Distance | 780 ± 30 ly (239 ± 8 pc) |
Details | |
A | |
Mass | 3.1±0.3[8] M☉ |
Surface gravity (log g) | 3.66±0.77[8] cgs |
Temperature | 10,651+932 −1156[8] K |
Metallicity [Fe/H] | 0.00[9] dex |
Rotational velocity (v sin i) | 217[10] km/s |
Age | 246[9] Myr |
B | |
Surface gravity (log g) | 4.14+0.19 −0.47[8] cgs |
Rotational velocity (v sin i) | 370[10] km/s |
Other designations | |
Database references | |
SIMBAD | data |
1 Delphini (1 Del) is the Flamsteed designation for a close binary star in the equatorial constellation Delphinus. With a combined apparent magnitude of 6.08, it is barely visible to the naked eye, even under ideal conditions. Parallax measurements put the components at a distance 703 and 780 light years respectively. However, its approaching the Solar System with a radial velocity of 15 km/s.
1 Del consists of three components. The brightest of them has a magnitude of 6.1; a companion located around 0.9 arcseconds from the primary has an apparent magnitude of 8.1; and a third star, located much farther away at around 17 arcseconds from component A, is the faintest with a magnitude of around 14 and is an unrelated background object.[11]
The entire system has a stellar classification of A1: III sh, indicating that it is a white giant + a shell star. However, there is some uncertainty about the temperature class. When resolved, the secondary has a class of B9. 1 Del A has 3 times the mass of the Sun and an effective temperature of 10,651 K,[8] giving it a bluish white glow. It is estimated to be almost 250 million years old and has a solar metallicity.[9] Both components spin rapidly, with projected rotational velocities of 217 and 370 km/s respectively.[10] As for the peculiarities, the shell star is a primary component; the spectrum of the secondary shows broad absorption lines.[10]
Due to the stability of the emission lines data from 1 Delphini has been used for developing models of shell stars and Be stars.[10]
EDR3A
was invoked but never defined (see the help page).Fabricius2002
was invoked but never defined (see the help page).EDR3B
was invoked but never defined (see the help page).Abt1995
was invoked but never defined (see the help page).Ducati
was invoked but never defined (see the help page).GCRV
was invoked but never defined (see the help page).Anderson2012
was invoked but never defined (see the help page).Anders2022
was invoked but never defined (see the help page).Gontcharov2012
was invoked but never defined (see the help page).kubat2016
was invoked but never defined (see the help page).EDR3C
was invoked but never defined (see the help page).