Alpha Pictoris
Template:Location mark Location of α Pictoris (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pictor |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 3.27[2] |
| Characteristics | |
| Spectral type | A8 Vn kA6[3] |
| U−B Template:Engvar | +0.13[2] |
| B−V Template:Engvar | +0.21[2] |
| Astrometry | |
| Radial velocity (Rv) | +20.6[4] km/s |
| Proper motion (μ) | RA: −66.07[1] mas/yr Dec.: +242.97[1] mas/yr |
| Parallax (π) | 33.78±1.78 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 0.86[5] |
| Orbit[6] | |
| Period (P) | Script error: No such module "val". days |
| Semi-major axis (a) | 3.25 AUTemplate:Efn |
| Eccentricity (e) | Script error: No such module "val". |
| Inclination (i) | Script error: No such module "val".° |
| Longitude of the node (Ω) | Script error: No such module "val".° |
| Periastron epoch (T) | Script error: No such module "val". BJD |
| Argument of periastron (ω) (secondary) | Script error: No such module "val".° |
| Details | |
| A | |
| Mass | Script error: No such module "val".[6] Template:Solar mass |
| Radius | 3.55[7] Template:Solar radius |
| Luminosity | Script error: No such module "val".[8] Template:Solar luminosity |
| Surface gravity (log g) | 3.48[9] cgs |
| Temperature | Script error: No such module "val".[8] K |
| Metallicity [Fe/H] | −0.11[3] dex |
| Rotational velocity (v sin i) | 206[10] km/s |
| Age | 660[11][12] Myr |
| B | |
| Mass | Script error: No such module "val".[6] Template:Solar mass |
| Temperature | Script error: No such module "val".[6] K |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| CD−61°1478, Gl 248, HD 50241, HIP 32607, HR 2550, LTT 2656, SAO 249647.[13] | |
| Database references | |
| SIMBAD | data |
Script error: No such module "Check for unknown parameters".
Alpha Pictoris (α Pic, α Pictoris) is the brightest star in the southern constellation of Pictor. It has an apparent visual magnitude of 3.27,[2] which is bright enough to be viewed from urban areas in the southern hemisphere. This is actually a binary star system, whose components complete an orbit every three years and seven months.[6] It is close enough for its distance to be measured using parallax shifts, which yields a value of roughly Script error: No such module "convert". from the Sun, with a 5% margin of error.[1] Alpha Pictoris has the distinction of being the south pole star of the planet Mercury.[14]
Properties
With an estimated age of 660 million years,[11][12] the primary component is a relatively young Lambda Boötis star.[15] The stellar classification of A8 Vn kA6[3] shows this peculiarity, with the kA6 notation indicating weaker than normal calcium K-lines in the spectrum. The 'n' following the main sequence luminosity class of V indicates the absorption lines in the spectrum are broad and nebulous. This is caused by the rapid spin of the star, which has a high projected rotational velocity of 206 km/s.[10] Spectroscopy shows narrow, time-varying absorption features being caused by circumstellar gas moving toward the star. This is not the result of interstellar matter, but a shell of gas along the orbital plane. Alpha Pictoris is categorized as a rapidly rotating shell star that may have recently ejected mass from its outer atmosphere.[9][16]
Alpha Pictoris A is larger than the Sun, with a 60% greater mass[6] and a 355% greater radius.[7] It is radiating 40 times as much luminosity as the Sun from its outer atmosphere at an effective temperature of Script error: No such module "val"..[8] At this heat, the star glows with the white hue of an A-type star.[17] It is also one of the brightest known Delta Scuti variables.[18] The space velocity components of this star in the galactic coordinate system are U = -22, V = -20 and W = -9 km/s.[19]
Data from the Hipparcos mission uncovered the presence of a binary companion[15] with a companion orbiting at a semimajor axis of around 3.25 AU, or three times the distance from Earth to the Sun.[6] Alpha Pictoris is an X-ray source, which is unusual for an A-type star since stellar models don't predict them to have magnetic dynamos. This emission may instead be originating from the companion.[9][20]
Notes
References
<templatestyles src="Reflist/styles.css" />
- ↑ a b c d e f Script error: No such module "Citation/CS1".
- ↑ a b c d Script error: No such module "Citation/CS1".
- ↑ a b c Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ a b c d e f g Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1". Alpha Pictoris' database entry at VizieR.
- ↑ a b c Script error: No such module "Citation/CS1". Alpha Pictoris' database entry at VizieR.
- ↑ a b c Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Template:Cite simbad
- ↑ Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
Script error: No such module "Check for unknown parameters".