_(noao-m40).jpg) Winnecke 4 double star | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major[1] |
| A | |
| Right ascension | 12h 22m 12.5272s[2] |
| Declination | +58° 4′ 58.549″[2] |
| Apparent magnitude (V) | 9.64[3] |
| B | |
| Right ascension | 12h 22m 18.9992s[4] |
| Declination | +58° 5′ 10.366″[4] |
| Apparent magnitude (V) | 10.11[3] |
| Characteristics | |
| A | |
| Spectral type | K0 III[5] |
| B | |
| Spectral type | G0 V[5] |
| Astrometry | |
| A | |
| Parallax (π) | 3.2191±0.0118 mas[2] |
| Distance | 1,013 ± 4 ly (311 ± 1 pc) |
| Absolute magnitude (MV) | +0.88[5] |
| B | |
| Parallax (π) | 6.9328±0.0155 mas[4] |
| Distance | 470 ± 1 ly (144.2 ± 0.3 pc) |
| Absolute magnitude (MV) | +4.0[5] |
| Details | |
| A | |
| Mass | 1.15[6] M☉ |
| Radius | 4.48[7] R☉ |
| Luminosity | 13[7] L☉ |
| Surface gravity (log g) | 3.16[6] cgs |
| Temperature | 4,957[6] K |
| Metallicity[Fe/H] | −0.164[8] dex |
| Age | 4.1[8] Gyr |
| B | |
| Mass | 1.00[6] M☉ |
| Radius | 1.1[9] R☉ |
| Luminosity | 1.56[9] L☉ |
| Surface gravity (log g) | 4.36[6] cgs |
| Temperature | 6,146[6] K |
| Metallicity[Fe/H] | −0.26[6] dex |
| Other designations | |
| M40,WNC 4,BD+56 1372,CCDM 12223+5805,WDS J12222+5805 | |
| A:HD 238107,SAO 28353 | |
| B:HD 238108,SAO 28355 | |
| Database references | |
| SIMBAD | data |
| A | |
| B | |
Winnecke 4 (also known asMessier 40 orWNC 4) is anoptical double star consisting of two unrelated stars in a northerly zone of the sky,Ursa Major.
The pair were discovered byCharles Messier in 1764 while he was searching for a nebula that had been reported in the area byJohannes Hevelius. Not seeing any nebulae, Messier catalogued this apparent pair instead. The pair were rediscovered byFriedrich August Theodor Winnecke in 1863, and included in theWinnecke Catalogue of Double Stars as number 4.Burnham calls M40 "one of the few real mistakes in theMessier catalog," faulting Messier for including it when all he saw was a double star, not a nebula of any sort.[10]
In 1991 the separation between the components was measured at 51.7″, an increase since 1764. Data gathered by astronomers Brian Skiff (2001) and Richard L. Nugent (2002) strongly suggested the subject was merely anoptical double star rather than a physically connected (binary) system.[5] The A star that seems the brighter is over twice as far as B.[11] Parallax measurements from theGaia satellite show the two stars, HD 238107 and HD 238108, are at distances of 311 ± 1parsec (1,013 ± 4light-years) and 144.2 ± 0.3parsecs (470 ± 1light-year) respectively. HD 238108 is itself a genuine binary star, with an 18th magnitudewhite dwarf companion 5 arcseconds away and a parallax distance of 146.8 ± 2.3parsecs (479 ± 8light-years).[citation needed]
Media related toMessier 40 at Wikimedia Commons
