  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Telescopium |
| A | |
| Right ascension | 20h 21m 41.03652s [1] |
| Declination | −49° 59′ 57.9001″ [1] |
| Apparent magnitude (V) | 6.27 [2] |
| B | |
| Right ascension | 20h 21m 39.11678s [3] |
| Declination | −49° 59′ 47.2058″ [3] |
| Apparent magnitude (V) | 12.8 [4] |
| Characteristics | |
| A | |
| Spectral type | F9 V [5] |
| U−B color index | –0.02 [2] |
| B−V color index | +0.55 [2] |
| B | |
| Spectral type | M2.5 [6] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | 16.9±0.65 [7] km/s |
| Proper motion (μ) | RA: −357.855 mas/yr [1] Dec.: −250.604 mas/yr [1] |
| Parallax (π) | 32.0547±0.0415 mas [1] |
| Distance | 101.7 ± 0.1 ly (31.20 ± 0.04 pc) |
| Absolute magnitude (MV) | +3.80 [8] |
| B | |
| Radial velocity (Rv) | 18.33±0.39 [9] km/s |
| Proper motion (μ) | RA: −350.120 mas/yr [3] Dec.: −252.474 mas/yr [3] |
| Parallax (π) | 32.0177 ± 0.0193 mas [3] |
| Distance | 101.87 ± 0.06 ly (31.23 ± 0.02 pc) |
| Details | |
| A | |
| Mass | 1.15±0.16 [10] M☉ |
| Radius | 1.49±0.07 [11] R☉ |
| Luminosity | 2.605±0.006 [1] L☉ |
| Surface gravity (log g) | 4.11±0.03 [12] cgs |
| Temperature | 6,059+96 −59 [13] K |
| Metallicity [Fe/H] | −0.34±0.06 [14] dex |
| Rotational velocity (v sin i) | <5 [15] km/s |
| Age | 7.55+0.62 −0.85 [12] Gyr |
| Other designations | |
| WDS J20217-5000AB [16] | |
| A: 86 G. Telescopii [17] , CD–50°12929, CPD−50°11341, FK5 3630, GC 28291, GJ 9691, HD 193307, HIP 100412, HR 7766, SAO 246546 [16] | |
| B: WT 703 | |
| Database references | |
| SIMBAD | A |
| B | |
HD 193307 (HR 7766; Gliese 9691) is the primary of a binary star located the southern constellation Telescopium. It has an apparent magnitude of 6.27, [2] placing it near the limit for naked eye visibility, even under ideal conditions. The star is located relatively close at a distance of 102 light years based on Gaia DR3 parallax measurements, [1] but it is receding with a heliocentric radial velocity of 16.9 km/s . [7] At its current distance, HD 193307's brightness is diminished by 0.18 magnitudes due to extinction from interstellar dust [18] and it has an absolute magnitude of +3.80. [8] HD 193307 has a relatively high proper motion, moving at a rate of 437 mas/yr. [19]
There have been disagreements in the stellar classification of the object. Two sources give a class of F9 V, [5] indicating that it is an ordinary F-type main-sequence star. David Stanley Evans gave it a slightly more evolved class of G2 IV-V, [20] meaning that it is a G-type star with a luminosity class intermediate between a subgiant and main sequence star. Nancy Houk's spectral classification catalog lists HD 193307 as G0 V. [21]
The accepted class for HD 193307 is F9 V. [5] The object's current luminosity is 1.49 magnitudes above the ZAMS, indicating that HD 193307 is somewhat evolved. [22] has 1.15 times the Sun's mass and a slightly enlarged radius of 1.49 R☉. [11] It radiates 2.61 times the luminosity of the Sun [1] from its photosphere at an effective temperature of 6,059 K , [13] which gives it the typical whitish-yellow hue of a late F-type star. At the age of 7.55 billion years, [12] HD 193307 has nearly twice the Sun's age. The star is metal-deficient with an iron abundance 46% that of the Sun ([Fe/H] = −0.34) [14] and it spins slowly with a projected rotational velocity lower than 5 km/s . [15]
WT 703 is a 12th magnitude star located 21.3" away along a position angle of 300°. It has a class of M2.5, indicating that it is a M-type star. [4] WT 703 is located around the same distance as HD 193307 and it has a similar proper motion.
