HD 73256
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| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pyxis |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 8.08[2] |
| Characteristics | |
| Spectral type | G8 IV-V Fe+0.5[3] |
| B−V Template:Engvar | Script error: No such module "val".[2] |
| Variable type | BY Dra[4] |
| Astrometry | |
| Radial velocity (Rv) | Script error: No such module "val".[1] km/s |
| Proper motion (μ) | RA: Script error: No such module "val". mas/yr[1] Dec.: Script error: No such module "val". mas/yr[1] |
| Parallax (π) | 27.2441±0.0217 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 5.20[2] |
| Details[5] | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Luminosity | Script error: No such module "val". Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | Script error: No such module "val".[6] dex |
| Rotational velocity (v sin i) | Script error: No such module "val".[6] km/s |
| Age | Script error: No such module "val". Gyr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[7] | |
| Database references | |
| SIMBAD | data |
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HD 73256 is a variable star in the southern constellation of Pyxis. It has the variable star designation CS Pyxidis. With a baseline apparent visual magnitude of 8.08,[2] it requires binoculars or a small telescope to view. The star is located at a distance of 120 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +30 km/s.[2]
The stellar classification of this star is G8IV-VFe+0.5, which suggests a slightly evolved G-type main-sequence star with a mild overabundance of iron in the spectrum. It is a BY Draconis variable with a period of 13.97 days, showing a variation of 0.03 in magnitude due to chromospheric activity.[4] The star appears overluminous for its class, which may be the result of a high metallicity.[6] The star has roughly the same mass and a slightly smaller radius as the Sun, but is radiating 74% of the Sun's luminosity.[5] It is around 2–3 billion years old and is spinning with a projected rotational velocity of 3.2 km/s.[6]
Planetary system
In 2003, S. Udry and colleagues reported the discovery of a planet in orbit around HD 73256 using data from the CORALIE spectrograph. This object is a hot Jupiter with at least 1.87 times the mass of Jupiter in an orbit with a period of 2.55 days.[6] Assuming the planet is perfectly grey with no greenhouse or tidal effects, and a Bond albedo of 0.1, the temperature would be about 1300 K. This is close to 51 Pegasi b; between the predicted temperatures of HD 189733 b and HD 209458 b (1180-1392K), before they were measured. It is a candidate for "near-infrared characterisation with the VLTI Spectro-Imager".[8]
In 2018, K. Ment and colleagues reported an attempt to confirm the existence of this planet using Keck/HIRES data, but were unable to do so despite a likelihood of success. Thus the existence of this object is disputed.[9]
In 2023, a different substellar companion on a wide orbit, likely a brown dwarf, was discovered using both radial velocity and astrometry. This study did also detect HD 73256 b, but did not update its parameters or address the dispute.[10]
Template:OrbitboxPlanet begin Template:OrbitboxPlanet hypothetical Template:OrbitboxPlanet
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See also
References
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