EU Andromedae

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EU Andromedae
EUAndLightCurve.png
A visual band light curve for EU Andromedae, from AAVSO data [1]
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 [2]   mas
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
2MASS J23195888+4714345, TYC 3640-752-1
Database references
SIMBAD data

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]

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]

Related Research Articles

Z Andromedae is a binary star system consisting of a red giant and a white dwarf. It is the prototype of a type of cataclysmic variable star known as symbiotic variable stars or simply Z Andromedae variables. The brightness of those stars vary over time, showing a quiescent, more stable phase and than an active one with a more pronounced variability and stronger brightening and/or dimming.

R Andromedae Star in the constellation Andromeda

R Andromedae is a Mira-type variable star in the constellation Andromeda. Its spectral class is type S because it shows absorption bands of zirconium monoxide (ZrO) in its spectrum. It was among the stars found by Paul Merrill to show absorption lines of the unstable element technetium, establishing that nucleosynthesis must be occurring in stars. The SH molecule was found for the first time outside earth in the atmosphere of this star. The star is losing mass due to stellar winds at a rate of 1.09×106M/yr.

OU Andromedae Star in the constellation Andromeda

OU Andromedae is a rotationally variable star in the constellation Andromeda. Varying between magnitudes 5.87 and 5.94, it has been classified as an FK Comae Berenices variable, but the classification is still uncertain. It has a spectral classification of G1IIIe, meaning that it is a giant star that shows emission lines in its spectrum. It is also likely in its horizontal branch phase of evolution.

HD 224801, also known as CG Andromedae, is an Alpha² Canum Venaticorum variable star in the constellation Andromeda. Located approximately 188 parsecs (610 ly) away, the star varies between apparent magnitudes 6.32 and 6.42 over a period of approximately 3.74 days.

IRC +10420 Yellow hypergiant star in the constellation Aquila

IRC+10420, also known as V1302 Aql, is a yellow hypergiant star located in the constellation of Aquila at a distance of 4-6 kiloparsecs of the Sun or only at 1.72 kiloparsecs using its Gaia Data Release 2 parallax.

HD 256 is a binary star system in the equatorial constellation of Cetus. It has a white hue and is dimly visible to the naked eye with an apparent visual magnitude of 6.20. Based upon parallax measurements, the system is located at a distance of approximately 474 light years from the Sun. It is drifting closer with a radial velocity of −10 km/s.

S Cassiopeiae Star in the constellation Cassiopeia

S Cassiopeiae is a Mira variable and S-type star in the constellation Cassiopeia. It is an unusually cool star, rapidly losing mass and surrounded by dense gas and dust producing masers.

IK Tauri or NML Tauri is a Mira variable star located about 280 parsecs (910 ly) from the Sun in the zodiac constellation of Taurus.

TU Andromedae Star in the constellation Andromeda

TU Andromedae is a variable star of the Mira type in the constellation Andromeda. It has a spectral type of M5e and a visual magnitude which varies between extremes of 7.6 and 13.5.

LQ Andromedae is a variable star in the constellation Andromeda. Its maximum apparent visual magnitude is 6.5, placing it at the limit of the visibility to the naked eye. The brightness, however, drops down to 6.66 with a periodic cycle of roughly 7.44 hours.

AD Andromedae Star in the constellation Andromeda

AD Andromedae is an eclipsing binary in the constellation Andromeda. Its maximum apparent visual magnitude is 11.2, but it shows a decrease of 0.62 magnitudes during the main eclipse and 0.58 during the secondary one. It is classified as a Beta Lyrae variable star with a period of almost one day.

AR Andromedae Star in the constellation Andromeda

AR Andromedae is a dwarf nova of the SS Cygni type in the constellation Andromeda. Its typical apparent visual magnitude is 17.6, but increases up to 11.0 magnitude during outbursts. The outbursts occur approximately every 23 days.

BM Andromedae is a T Tauri star in the constellation Andromeda. Its apparent visual magnitude has irregular variations between a maximum of 11.63 and a minimum of 14.02.

DX Andromedae Star in the constellation Andromeda

DX Andromedae is a cataclysmic variable star in the constellation Andromeda. It has a typical apparent visual magnitude of 15.5 during the quiescent phase, but becomes brighter during outbursts recurring with a mean cycle length of 330 days, thus is classified as a dwarf nova of the SS Cygni type.

FF Andromedae Star in the constellation Andromeda

FF Andromedae is a spectroscopic binary in the constellation Andromeda. It has a typical apparent visual magnitude of 10.4, but undergoes flare events that can increase its brightness by about a magnitude.

GR Andromedae Star in the constellation Andromeda

GR Andromedae is a variable star in the constellation Andromeda. Its apparent visual magnitude varies between 6.87 and 6.95 in a cycle of 518.2 days. It is classified as an α2 Canum Venaticorum variable.

HN Andromedae Star in the constellation Andromeda

HN Andromedae is a variable star in the constellation Andromeda. Its apparent visual magnitude varies between 6.67 and 6.76 in a cycle of 69.51 days. It is classified as an α2 Canum Venaticorum variable.

KX Andromedae is a spectroscopic binary star in the constellation Andromeda. Its apparent visual magnitude varies between 6.88 and 7.28.

LP Andromedae is a carbon star in the constellation Andromeda. It is also a Mira variable whose mean apparent visual magnitude is 15.12 and has pulsations with an amplitude of 1.50 magnitudes and a period of 614 days.

R Fornacis Variable star in the constellation Fornax

R Fornacis is a Mira variable and carbon star located in the constellation Fornax. It is around 1,800 light years away based on parallax measurements.

References

  1. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  2. 1 2 3 4 5 6 7 8 9 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.
  3. 1 2 3 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.
  4. 1 2 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.
  5. 1 2 3 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.
  6. 1 2 3 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.
  7. 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.
  8. 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.
  9. 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.