Summary
EU Andromedae (often abbreviated to EU And) is a carbon star in the constellation Andromeda. Its apparent visual magnitude varies in an irregular manner between 10.7 and 11.8.[3]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h 19m 58.8815s[2] |
| Declination | +47° 14′ 34.576″[2] |
| Apparent magnitude (V) | 10.7 – 11.8 variable [3] |
| Characteristics | |
| Spectral type | C-J5− C25 j3.5[4] |
| Apparent magnitude (B) | 12.84[5] |
| Apparent magnitude (V) | 10.38[5] |
| Apparent magnitude (G) | 9.0005[2] |
| Apparent magnitude (J) | 5.526[6] |
| Apparent magnitude (H) | 4.492[6] |
| Apparent magnitude (K) | 4.018[6] |
| B−V color index | 2.5687[5] |
| Variable type | Lb?[3] |
| Astrometry | |
| Proper motion (μ) | RA: 2.062±0.080 [2] mas/yr Dec.: −3.263±0.072[2] mas/yr |
| Parallax (π) | 0.6515 ± 0.0561 mas[2] |
| Distance | 5,000 ± 400 ly (1,500 ± 100 pc) |
| Details | |
| Radius | 82[2] R☉ |
| Luminosity | 983[2] L☉ |
| Temperature | 3,579[2] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Infrared observations of EU Andromedae show the presence of silicate grains, indicating the presence of an oxygen-rich circumstellar shell around the star, a combination known as a silicate star. Subsequently, a water maser was detected around this star (and for the first time around a carbon star), confirming the existence of the shell.[7] The most recent observations suggest that the maser originated in a circumstellar disc, seen nearly edge-on, around an unseen companion with a minimum mass of 0.5 M☉. Carbon dioxide has been detected for the first time in a silicate carbon star around EU Andromedae.[8][9]
EU Andromedae is given as the standard star for the C-J5− spectral class. C-J spectral types are assigned to stars with strong isotopic bands of carbon molecules, defined as the ratio of 12
C
to 13
C
being less than four. A more complete spectral type includes the abundance indices C25 j3.5, which indicate the Swan band strength and the isotopic band ratio.[4]
References edit
- ^ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
- ^ a b c d e f g h i Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c EU And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2018-10-17.
- ^ a b Barnbaum, Cecilia; Stone, Remington P. S.; Keenan, Philip C. (1996). "A Moderate-Resolution Spectral Atlas of Carbon Stars: R, J, N, CH, and Barium Stars". The Astrophysical Journal Supplement Series. 105: 419. Bibcode:1996ApJS..105..419B. doi:10.1086/192323.
- ^ a b c Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
- ^ a b c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ Benson, P. J.; Little-Marenin, I. R. (1987). "A Water Maser Associated with EU Andromedae: A Carbon Star near an Oxygen-rich Circumstellar Shell". Astrophysical Journal Letters. 316: L37. Bibcode:1987ApJ...316L..37B. doi:10.1086/184887.
- ^ Ohnaka, K.; Boboltz, D. A. (2008). "Imaging the oxygen-rich disk toward the silicate carbon star EU Andromedae". Astronomy and Astrophysics. 478 (3): 809–814. arXiv:0712.2395. Bibcode:2008A&A...478..809O. doi:10.1051/0004-6361:20079030. S2CID 55988822.
- ^ Lloyd Evans, T. (1990). "Carbon stars with silicate dust shells - I. Carbon stars with enhanced 13C (J stars)". Monthly Notices of the Royal Astronomical Society. 243: 336. Bibcode:1990MNRAS.243..336L.