HJ 4093
Quadruple star system in the constellation Puppis
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HJ 4093 (WDS J08263-3904) is a star system in the constellation Puppis. It comprises HD 71487 and HD 71488, which together form a visual binary and are themselves close binary systems, making HJ 4093 a four-star system. They are separated by about 1,400 astronomical units, having an estimated orbital period in the order of 10,000 years.[4] The combined apparent magnitude is 6.07,[12] making the system (faintly) visible to the naked eye only in ideal conditions, within places far from light pollution.[13]
(6.588 + 8.96)[4]
primary eclipse: 6.98[5]
secondary ecl.: 6.66[5]
(7.900 + 8.10)[7]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis[1][2] |
| HD 71487 | |
| Right ascension | 08h 26m 17.7301s[3] |
| Declination | −39° 03′ 32.258″[3] |
| Apparent magnitude (V) | 6.49±0.01 (6.588 + 8.96)[4] primary eclipse: 6.98[5] secondary ecl.: 6.66[5] |
| HD 71488 | |
| Right ascension | 08h 26m 18.3057s[6] |
| Declination | −39° 03′ 36.747″[6] |
| Apparent magnitude (V) | 7.40[4] (7.900 + 8.10)[7] |
| Characteristics | |
| HD 71487 | |
| Evolutionary stage | Main sequence[4] |
| Spectral type | B9V + A7V[4] |
| B−V color index | −0.11[4] |
| Variable type | Eclipsing binary[8] |
| HD 71488 | |
| Evolutionary stage | Main sequence[4] |
| Spectral type | A5V + A6V[4] |
| B−V color index | +0.30[4] |
| Astrometry | |
| HD 71487 | |
| Radial velocity (Rv) | +25.4±0.6[9] km/s |
| Proper motion (μ) | RA: −7.896 mas/yr[3] Dec.: +5.975 mas/yr[3] |
| Parallax (π) | 5.7991±0.0304 mas[3] |
| Distance | 562 ± 3 ly (172.4 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.258±0.409[4] |
| HD 71488 | |
| Proper motion (μ) | RA: −6.1±2.0 mas/yr[6] Dec.: +10.4±2.9 mas/yr[6] |
| Position (relative to HD 71487)[7] | |
| Component | HD 71488 |
| Epoch of observation | 2015 |
| Angular distance | 8.1″ |
| Position angle | 124° |
| Orbit[4] | |
| Primary | HD 71487 A |
| Name | HD 71487 B |
| Period (P) | 1.2569956(9) days |
| Semi-major axis (a) | 0.03956±0.00023 au (8.51±0.05 R☉) |
| Eccentricity (e) | 0.127±0.027 |
| Inclination (i) | 81.33±0.20° |
| Semi-amplitude (K1) (primary) | 109.9±0.9 km/s |
| Semi-amplitude (K2) (secondary) | 232.1±1.5 km/s |
| Orbit[4] | |
| Primary | HD 71488 A |
| Name | HD 71488 B |
| Period (P) | 101.3±3.8 years |
| Semi-major axis (a) | 0.179±0.012" (34.4 au) |
| Eccentricity (e) | 0.054±0.041 |
| Inclination (i) | 155±13° |
| Longitude of the node (Ω) | 47±71° |
| Periastron epoch (T) | 1976.23±13.06 |
| Argument of periastron (ω) (secondary) | 318±74° |
| Details[4] | |
| HD 71487 A | |
| Mass | 3.58±0.11 M☉ |
| Radius | 2.17±0.03 R☉ |
| Luminosity | 133±24 L☉ |
| Surface gravity (log g) | 4.3±0.1 cgs |
| Temperature | 13,300±500 K |
| Metallicity [Fe/H] | −0.02±0.01 dex |
| Rotation | 1.32 days |
| Rotational velocity (v sin i) | 65±5 km/s |
| Age | 20 Myr |
| HD 71487 B | |
| Mass | 1.68±0.09 M☉ |
| Radius | 1.51±0.06 R☉ |
| Luminosity | 6.2±2.2 L☉ |
| Surface gravity (log g) | 4.2±0.1 cgs |
| Temperature | 7,400±500 K |
| Metallicity [Fe/H] | −0.08±0.03 dex |
| Rotational velocity (v sin i) | 64±2 km/s |
| Age | 20 Myr |
| HD 71488 A | |
| Mass | 2.0 M☉ |
| Age | 20 Myr |
| HD 71488 B | |
| Mass | 1.8 M☉ |
| Age | 20 Myr |
| Other designations | |
| HJ 4093, B 1605, CD−38°4462, HIP 41361, CCDM J08263-3904, WDS J08263-3904[10][11] | |
| HD 71487: NO Puppis, HR 3327, SAO 199222, TYC 7661-4332-1[10] | |
| HD 71488: HR 3328, SAO 199224, TYC 7661-4332-2[11] | |
| Database references | |
| SIMBAD | HD 71487 |
| HD 71488 | |
Parallax measurements by the Gaia spacecraft place HJ 4093 at a distance of 172±1 parsecs (562±3 light-years).[3][a] The system is very young, at 20 million years old,[4] and is part of an unnamed stellar association.[14]
HD 71487
HD 71487, also called HJ 4093 A and more frequently NO Puppis,[9][4][12] is an eclipsing binary with an orbital period of 1.256 days.[4] The overall apparent magnitude is 6.49,[4] and during the primary (deeper) and secondary eclipse it drops to 6.98 and 6.66, respectively.[5] The variability of this system was announced in 1972 by B. G. Jorgensen.[16] When using a designation about the entire system (e.g. HJ 4093), the primary and secondary are referred to as Aa and Ab, respectively,[7] but when using a specific designation (e.g. HD 71487) they may simply be called "A" and "B".[b]
The components have stellar classifications of B8V and A7V, suggesting they are hot main sequence stars. NO Puppis A has 3.58 times the mass (M☉) and 2.17 times the radius (R☉), while NO Puppis B has 1.68 times the mass and 1.51 times the radius of the Sun. The effective temperature of A is 13,300 K,[4] giving it the blue-white hue typical of a late B-type star,[17] while that of component B is 7,400 K,[4] giving it the whitish hue typical of a late A-type star.[17] NO Puppis A lies in the instability strip of slowly pulsating B-type stars and is likely of this variable star class, while NO Puppis B lies in the instability strip of Delta Scuti variables and appears to exhibit δ Scuti-like pulsations.[4]
The stars are separated by 8.5 R☉ and have an orbital eccentricity of 0.13, which is unusually high for such a close binary system, given that an orbit with such a separation would be expected to be nearly circular. At some point the system may have had several more components that were ejected due to gravitational perturbations, inducing a high eccentricity for this system.[4]
HD 71488
HD 71488, also called HJ 4093 B, is an astrometric binary system with an apparent magnitude is 7.27. The components have an orbital period of 100 years.[4] When using a designation about the entire system (e.g. HJ 4093), the primary and secondary are referred to as Ba and Bb, respectively, or sometimes as B and C, as in CCDM J08263-3904BC.[11] When using a specific designation (e.g. HD 71488) they can be called simply "A" and "B". Based on its estimated absolute magnitude and mass–luminosity relations, HD 71488 A is expected to have a spectral type of A5V and an estimated mass of 2.0 M☉, while HD 71488 B would have a spectral type of A6V and an estimated 1.8 times the mass of the Sun,[4] although direct observations give a combined spectral class of A2Va.[18]
Notes
- The distance of 173.7173 parsecs published in Gaia DR3 is based on spectra rather than parallax.