Eta Apodis
Template:Location mark Location of η Apodis (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus[1] |
| Right ascension | Template:RA[2] |
| Declination | Template:DEC[2] |
| Apparent magnitude (V) | +4.89[3] |
| Characteristics | |
| Spectral type | A2MA7-F2[4] or A2(m) CrEu[5] |
| U−B Template:Engvar | +0.11[6] |
| B−V Template:Engvar | +0.25[6] |
| Variable type | α2 CVn[7] |
| Astrometry | |
| Radial velocity (Rv) | −9.4[3] km/s |
| Proper motion (μ) | RA: −19.981 mas/yr[2] Dec.: −65.222 mas/yr[2] |
| Parallax (π) | 22.9229±0.1180 mas[2] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | +1.76[1] |
| Details | |
| Mass | 1.77[8] Template:Solar mass |
| Radius | 2.13[8] Template:Solar radius |
| Luminosity | 15.5[8] Template:Solar luminosity |
| Temperature | Script error: No such module "val".[8] K |
| Rotational velocity (v sin i) | 17.2±0.3[9] km/s |
| Age | 250±200[8] Myr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[10] | |
| Database references | |
| SIMBAD | data |
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Eta Apodis is a star in the southern circumpolar constellation Apus. Its identifier is a Bayer designation that is Latinized from η Apodis, and abbreviated Eta Aps or η Aps, respectively. Based upon parallax measurements from Gaia Data Release 3, it is Script error: No such module "convert". from Earth. It is drifting closer with a heliocentric radial velocity of −9 km/s.[3] With an apparent visual magnitude of +4.9, it can be viewed with the naked eye from the southern hemisphere.
Properties
This star has about 1.77 times the mass of the Sun and 2.13 times the Sun's radius. It is radiating 15.5 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 7,860 K.[8] Eta Apodis is a young star with an age of about 250 million years,[8] and is spinning with a projected rotational velocity of 17 km/s.[9]
The stellar classification of Eta Apodis shows this to be an Am star, which means the spectrum shows chemically peculiarities. In particular, it is an A2-type star showing an excess of the elements chromium and europium. The spectrum displays magnetically-induced features indicating an estimated surface field strength of roughly Script error: No such module "val"..[5] Data from the TESS satellite found it to be an Alpha2 Canum Venaticorum-type variable star,[7] consistent with its magnetic and chemical properties.[11] The variability range is only a thousandth of a magnitude.[7]
Based upon observations with the Spitzer Space Telescope, this system is emitting an excess of 24 μm infrared radiation. This may be caused by a debris disk of dust orbiting at a distance of more than 31 astronomical units from the star.[8]
Naming
In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Exotic Bird, refers to an asterism consisting of η Apodis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ1 Apodis, α Apodis and ε Apodis. Consequently, η Apodis itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.)[12]
References
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- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c d Template:Cite Gaia DR3
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- ↑ a b Script error: No such module "citation/CS1".
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- ↑ Script error: No such module "citation/CS1".
- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日 Template:Webarchive
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