HD 74438
Quadruple star system in the constellation Ursa Major
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HD 74438 is a spectroscopic quadruple stellar system composed of a pair of double star systems approximately 425 light years from Earth, located in the open cluster IC 2391.[7][8] With an estimated age of 43+15
−7 million years,[6] HD 74438 is the youngest quadruple star system known.[9] The outer orbital period of the system, estimated at around 5.7 years, is also among the shortest of quadruple systems.[6][9]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela[1] |
| Right ascension | 08h 41m 46.5806s[2] |
| Declination | −52° 03′ 44.996″[2] |
| Apparent magnitude (V) | +7.59 (8.2/8.2/9.4/9.4)[3] |
| Characteristics | |
| Spectral type | A2mA5-A8[4] |
| Astrometry | |
| Proper motion (μ) | RA: −17.745[2] mas/yr Dec.: +17.056[2] mas/yr |
| Parallax (π) | 6.9075±0.0755 mas[2] |
| Distance | 472 ± 5 ly (145 ± 2 pc) |
| Absolute magnitude (MV) | +3.23[5] |
| Orbit[6] | |
| Primary | AB |
| Name | CD |
| Period (P) | 2,074.2±3.5 days |
| Semi-major axis (a) | 5.54±0.04 au |
| Eccentricity (e) | 0.458±0.015 |
| Inclination (i) | 73.2 or 106.8° |
| Semi-amplitude (K1) (primary) | 12.8±0.3 km/s |
| Semi-amplitude (K2) (secondary) | 18.5±0.4 km/s |
| Orbit[6] | |
| Primary | A |
| Name | B |
| Period (P) | 20.5729±0.0003 days |
| Semi-major axis (a) | 0.215±0.002 au |
| Eccentricity (e) | 0.3692±0.0001 |
| Inclination (i) | 52.5 or 127.5° |
| Semi-amplitude (K1) (primary) | 45.81±0.09 km/s |
| Semi-amplitude (K2) (secondary) | 50.77±0.09 km/s |
| Orbit[6] | |
| Primary | C |
| Name | D |
| Period (P) | 4.4243±0.0001 days |
| Semi-major axis (a) | 0.0681±0.001 au |
| Eccentricity (e) | 0.1535±0.0003 |
| Inclination (i) | 84.0 or 96.0° |
| Semi-amplitude (K1) (primary) | 45.81±0.09 km/s |
| Semi-amplitude (K2) (secondary) | 50.77±0.09 km/s |
| Details[6] | |
| A | |
| Mass | 1.70±0.06 M☉ |
| Radius | 1.46±0.15 R☉ |
| Luminosity | 8.87±1.40 L☉ |
| Temperature | 8,250±250 K |
| B | |
| Mass | 1.54±0.06 M☉ |
| Radius | 1.42±0.15 R☉ |
| Luminosity | 5.72±0.95 L☉ |
| Temperature | 7,500±250 K |
| C | |
| Mass | 0.96±0.14 M☉ |
| Radius | 0.84±0.36 R☉ |
| Luminosity | 0.64±0.51 L☉ |
| Temperature | 5,625±410 K |
| D | |
| Mass | 0.87±0.14 M☉ |
| Radius | 0.80±0.29 R☉ |
| Luminosity | 0.48±0.32 L☉ |
| Temperature | 5,375±410 K |
| Other designations | |
| HD 74438, CD−52°2497, SAO 236190 | |
| Database references | |
| SIMBAD | data |
The HD 74438 system was confirmed to be a gravitationally bound quadruple system in 2017 from data collected in the Gaia-ESO Survey.[7] In a paper published in 2022, HD 74438 was identified as a possible progenitor of a sub-Chandrasekhar Type Ia supernova.[6]