| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 16h 34m 20.33027s[2] |
| Declination | +57° 09′ 44.3689″[2] |
| Apparent magnitude (V) | 12.87[3] |
| Characteristics | |
| Spectral type | M4.5V / M4.5V[4] / DQ8[5] |
| Variable type | BY Draconis variable Eclipsing binary Flare star |
| Astrometry | |
| Radial velocity (Rv) | –118.24[3] km/s |
| Proper motion (μ) | RA: –1113.797 mas/yr[2] Dec.: 1180.977 mas/yr[2] |
| Parallax (π) | 67.2876 ± 0.0337 mas[2] |
| Distance | 48.47 ± 0.02 ly (14.862 ± 0.007 pc) |
| Absolute magnitude (MV) | 12.1[citation needed] |
| Orbit[6] | |
| Period (P) | 1.2683900573(17) d |
| Semi-major axis (a) | 0.0173945(64) AU |
| Eccentricity (e) | 0.00527(21) |
| Inclination (i) | 89.5514±0.0020° |
| Longitude of the node (Ω) | 15.79[4]° |
| Argument of periastron (ω) (secondary) | 107.98±0.70° |
| Semi-amplitude (K1) (primary) | 72.23[4] km/s |
| Semi-amplitude (K2) (secondary) | 77.95[4] km/s |
| Details | |
| A | |
| Mass | 0.22507(24)[6] M☉ |
| Radius | 0.25113(16)[6] R☉ |
| Luminosity (bolometric) | 0.00552[4] L☉ |
| Surface gravity (log g) | 4.994±0.007[4] cgs |
| Temperature | 3130 ± 70[4] K |
| Metallicity [Fe/H] | −0.30±0.12[7] dex |
| Age | 4.1 ± 0.8[4] Gyr |
| B | |
| Mass | 0.21017(28)[6] M☉ |
| Radius | 0.23732(14)[6] R☉ |
| Luminosity (bolometric) | 0.00486[4] L☉ |
| Surface gravity (log g) | 5.009±0.006[4] cgs |
| Temperature | 3120 ± 70[4] K |
| Metallicity [Fe/H] | −0.30±0.12[7] dex |
| Age | 4.1 ± 0.8[4] Gyr |
| Other designations | |
| Eclipsing binary: CM Dra, GJ 630.1A, CCDM J16343+5710A, WDS J16345+5709A, LHS 421, LP 101-15, NLTT 43148, TIC 199574208[3] | |
| White dwarf: GJ 630.1B, CCDM J16343+5710B, WDS J16345+5709B, EGGR 258, LHS 422, LP 101-16, NLTT 43149, WD 1633+57, TIC 199574211[5] | |
| Database references | |
| SIMBAD | A |
| B | |
| ARICNS | A |
| B | |
CM Draconis (GJ 630.1A) is an eclipsing binary star system 48.5 light-years (14.9 parsecs) away in the constellation of Draco (the Dragon). The system consists of two nearly identical red dwarf stars that orbit each other with a period of 1.268 days and a separation of 2.6 million kilometres (0.017 AU).[6] Along with two stars in the triple system KOI-126, the stars in CM Draconis are among the lightest stars with precisely measured masses and radii. Consequently, the system plays an important role in testing stellar structure models for very low mass stars.[4] These comparisons find that models underpredict the stellar radii by approximately 5%. This is attributed to consequences of the stars' strong magnetic activity.[4]
According to the system's entry in the Combined General Catalogue of Variable Stars, at least one of the components is a flare star and at least one is a BY Draconis variable.[8] The white dwarf star GJ 630.1B, located 25.7 arcseconds away shares the same proper motion as the CM Draconis stars and is thus a true companion star of the system.[9] Given the system's distance of 47 light years,[10] this corresponds to a separation of at least 370 astronomical units between CM Draconis and GJ 630.1B.
- ^ Cite error: The named reference
Kozhevnikovawas invoked but never defined (see the help page). - ^ a b c d Cite error: The named reference
GaiaDR3was invoked but never defined (see the help page). - ^ a b c Cite error: The named reference
SIMBADwas invoked but never defined (see the help page). - ^ a b c d e f g h i j k l m n Cite error: The named reference
Moraleswas invoked but never defined (see the help page). - ^ a b Cite error: The named reference
SIMBAD2was invoked but never defined (see the help page). - ^ a b c d e f Cite error: The named reference
Martin2024was invoked but never defined (see the help page). - ^ a b Cite error: The named reference
Terrien2012was invoked but never defined (see the help page). - ^ Samus (2004). "CM Dra". Combined General Catalogue of Variable Stars.
- ^ Deeg, H. J.; Ocaña, B.; Kozhevnikov, V. P.; Charbonneau, D.; O'Donovan, F. T.; Doyle, L. R. (2008). "Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis". Astronomy and Astrophysics. 480 (2): 563–571. arXiv:0801.2186. Bibcode:2008A&A...480..563D. doi:10.1051/0004-6361:20079000. S2CID 10252705.
- ^ Gliese, W.; Jahreiß, H. (1991). "GJ 630.1A". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2008-10-12.