| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Andromeda[1] |
| Right ascension | 23h 39m 05.8103s[2] |
| Declination | +42° 27′ 57.505″[2] |
| Apparent magnitude (V) | +10.47[3] |
| Characteristics | |
| Spectral type | F8V[4] |
| B−Vcolor index | 0.41[3] |
| Variable type | planetary transit[5] |
| Astrometry | |
| Radial velocity (Rv) | −22.13(44)[6] km/s |
| Proper motion (μ) | RA: −20.202(18)mas/yr[2] Dec.: 2.996(18)mas/yr[2] |
| Parallax (π) | 3.6459±0.0221 mas[2] |
| Distance | 895 ± 5 ly (274 ± 2 pc) |
| Absolute magnitude (MV) | +3.36(16)[5] |
| Details | |
| Mass | 1.29 ± 0.06[7] M☉ |
| Radius | 1.46 ± 0.06[7] R☉ |
| Luminosity | 3.57+0.52 −0.43[5] L☉ |
| Surface gravity (log g) | 4.22 ± 0.03[8] cgs |
| Temperature | 6,570 ± 80[7] K |
| Metallicity [Fe/H] | –0.13 ± 0.08[7] dex |
| Rotational velocity (v sin i) | 8.7 ± 1.0[7] km/s |
| Age | 2.3+0.5 −0.7[7] Gyr |
| Other designations | |
| Sterrennacht,Gaia DR3 1925321658551399040,TYC 3239-992-1,GSC 03239-00992,2MASS J23390581+4227575[9] | |
| Database references | |
| SIMBAD | data |
HAT-P-6 also namedSterrennacht[10] is astar in theconstellationAndromeda, located approximately 895light years or 274parsecs away from theEarth. It is anF-type star, implying that it is hotter and more massive than theSun. Theapparent magnitude of the star is +10.54, which means that it can only be visible through thetelescope. Theabsolute magnitude of +3.36 is brighter than the Sun's +4.83, meaning that the star itself is brighter than the Sun.[5] A search for a binary companion star usingadaptive optics at theMMT Observatory turned out negative.[11]
The nameSterrennacht (Starry Night) was selected in theNameExoWorlds held by theIAU after a painting byVan Gogh.[10]
The companion planetHAT-P-6b is atransitingplanet discovered on October 15, 2007 by theHATNet Project. The planet'strue mass is slightly more than Jupiter at only 5.7%, but the radius is 33% greater, making the planet's density of 0.45 g/cm3. Its large size compared to mass comes from the great amount of heat received from the nearby star that expands the planet'satmosphere, categorizing as "hot Jupiter". The orbital period is 3.852985 days and the distance from its star is 0.05235 AU.[5] The inclination of the orbit with respect to the stellar rotation axis is roughly 166º.[12]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Nachtwacht | 1.106+0.039 −0.040 MJ | 0.05239+0.00080 −0.00082 | 3.852985±0.000005 | <0.044 | 166±10[12]° | 1.330±0.061 RJ |
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