Eta Andromedae (Eta And / η Andromedae / η And) adalah bintang ganda yang berada di rasi Andromeda. Sistem bintang ini terdiri dari dua bintang sub raksasa tipe G (G-type subgiant)]] dengan periode orbit 115.7 hari dan magnitudo keseluruhan 4.40.
Eta Andromeda A/B. | ||
Data pengamatan Epoch J2000.0 Equinox J2000.0 (ICRS) | ||
Rasi bintang | Andromeda | |
Asensio rekta | 00j 57m 12.4000d | |
Deklinasi | +23° 25′ 03.533″ | |
Magnitudo semu (V) | 4.403 | |
Karakteristik | ||
Klasifikasi bintang | G8III-IV | G8III-IV |
U-B Indeks warna | +0.69 | |
B-V Indeks warna | +0.94 | |
R-I Indeks warna | +0.48 | |
Astrometri | ||
Kecepatan radial (Rv) | −10.3 ± 0.9 km/d | |
Gerak diri: | ||
RA (μα cos δ) | −43.72 m.b/thn | |
Dec. (μδ) | −46.06 m.b/thn | |
Paralaks (π) | 13.44 ± 0.75 m.b | |
Jarak | 240 ± 10 tc (74 ± 4 pc) | |
Magnitudo mutlak (MV) | 0.52 ± 0.06 | 1.07 ± 0.07 |
Details | ||
Massa | 2.6 ± 0.35 M☉ | 2.3 ± 0.31 M☉ |
Gravitasi permukaan (log g) | 2.8 | 3.0 |
Luminositas (bolometriks) | 65 ± 3 L☉ | 39 ± 3 L☉ |
Temperatur | 4900 K | 4900 K |
Umur | 8×108 tahun | |
Orbit | ||
Periode (P) | 115.72 ± 0.01 d | |
Sumbu semi-mayor (a) | 10.37 ± 0.03 mas | |
Eksentrisitas (e) | 0.006 ± 0.002 | |
Inklinasi (i) | 30.5 ± 0.4° | |
Bujur node menaik (Ω) | 69.4 ± 0.5° | |
Periastron epos (T) | 48013 ± 1 MJD | |
Argumen periastron (ω) (secondary) | 215 ± 4° | |
Referensi Database | ||
SIMBAD | data | |
Nama lain | ||
η And, Eta Andromedae, Eta And, 38 Andromedae, 38 And, MKT 2, FOX 116A, BD+22°153, CCDM J00572+2325A, FK5 2060, GC 1136, HD 5516, HIP 4463, HR 271, IDS 00519+2253 A, PPM 90327, SAO 74388, WDS 00572+2325A/Aa. Entry 00572+2325, discoverer code MKT 2, components Aa, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line August 27, 2008.</ref> | ||
Sejarah pengamatan sunting
Eta Andromedae ditemukan dan diamati sebagai bintang ganda pada tahun 1899 dan 1900. Its orbit was computed in 1946 from spectroscopic observations. Pada pengamatan tahun 1990 sampai 1992, Eta Andromedae diamati melalui Mark III Stellar Interferometer di Mount Wilson Observatory, California, Amerika Serikat. Hasil pengamatini ini dilaporkan pada tahun 1993.
Lokasi sunting
Komponen visual sunting
Data pengamatan Epos J2000.0 Ekuinoks J2000.0 (ICRS) | |
---|---|
Rasi bintang | Andromeda |
Asensio rekta | 00j 57m 04.9d |
Deklinasi | +23° 23′ 43″ |
Magnitudo tampak (V) | 11.5 |
Posisi (relatif ke η And) | |
Epoch pengamatan | 1997 |
Jarak sudut | 129.2″ |
Sudut posisi | 232° Entry 00572+2325, discoverer code FOX 116, components AB, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line August 23, 2008.</ref> |
Referensi basis data | |
SIMBAD | data |
Penamaan lain | |
FOX 116B, BD+22°153B, CCDM J00572+2325B, IDS 00519+2253 B, WDS 00572+2325B. |
Bintang ini memiliki magnitudo 11.5, terpisah 129.2 arcsecond dari komponen utama.
Etimologi sunting
Nama lain yang diberikan oleh para astronom untuk bintang ini adalah:
Referensi sunting
- ^ HD 5516 -- Spectroscopic binary, database entry, SIMBAD. Accessed on line August 23, 2008. Kesalahan pengutipan: Tanda
<ref>
tidak sah; nama "sb0" didefinisikan berulang dengan isi berbeda - ^ The spectroscopic binary eta Andromedae: Determination of the orbit by optical interferometry, C. A. Hummel et al., Astronomical Journal 106, #6 (December 1993), pp. 2486–2492, Bibcode: 1993AJ....106.2486H, DOI:10.1086/116816.
- ^ HR 271, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line August 23, 2008.
- ^ Table 2, Resolved double-lined spectroscopic binaries: A neglected source of hypothesis-free parallaxes and stellar masses, D. Pourbaix, Astronomy and Astrophysics Supplement 145 (August 2000), pp. 215–222, Bibcode: 2000A&AS..145..215P.
- Entry 00572+2325, Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory. Accessed on line August 27, 2008.
- A list of nine stars whose velocities in the line of sight are variable, W. W. Campbell and W. H. Wright, Astrophysical Journal 12 (November 1900), pp. 254–257, Bibcode: 1900ApJ....12..254C, DOI:10.1086/140765.
- The Spectroscopic Binary η Andromedae, Katherine C. Gordon, Astrophysical Journal 103 (January 1946), pp. 13–15, Bibcode: 1946ApJ...103...13G.
- ^ BD+22 153B -- Star in double system, database entry, SIMBAD. Accessed on line August 22, 2008.
- salah satu rasi bintang menurut bangsa Cina
- http://www.atlascoelestis.com/alsufi%2020.htm
Pranala luar sunting
- η Andromedae 2009-08-27 di Wayback Machine. at Alycone Software's Star Data Pages
- Image η Andromedae