SU Andromeda ( Latin: SU Andromedae ) is a carbon star in the constellation Andromeda . It is a variable supergiant star belonging to the class of slow irregular variables , the apparent magnitude varies from 8.5 at the minimum of brightness to 8.0 at the maximum of brightness, the period is not reliably determined. [2]
| SU Andromeda | |||
|---|---|---|---|
| Star | |||
 SU Andromeda in the optical range | |||
| Observational data ( Age J2000.0 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | |||
| Visible magnitude ( V ) | 8.0 - 8.5 [2] | ||
| Constellation | Andromeda | ||
| Astrometry | |||
| Radial velocity ( R v ) | |||
| Own movement (μ) | RA: −3.362 ± 0.058 [1] Dec: −2.097 ± 0.040 [1] | ||
| Parallax (π) | 0.6979 ± 0.0439 [1] mas | ||
| Absolute magnitude (V) | −2.2 [5] | ||
| Characteristics | |||
| Spectral class | C6.4 (C5II) [2] | ||
| Color Index ( B - V ) | +2.58 [6] | ||
| Color Index ( U - B ) | +4.13 [6] | ||
| Variability | LC [2] | ||
| physical characteristics | |||
| Radius | / 1.95 [7] R ☉ | ||
| Temperature | 2905 [8] / 7311 [7] K | ||
| Luminosity | 2535 [8] / 9.833 [7] L ☉ | ||
| |||
| Database Information | |||
| SIMBAD | data | ||
Content
- 1 Variability
- 2 Spectrum
- 3 Companion Object
- 4 notes
Variability
Thomas Espin noted the possible variability of the star in 1895. [9] In 1906, William Fleming investigated photographic plates to create the Henry Draper catalog , when she independently discovered and confirmed the variability of this star. [10]
Spectrum
The Andromeda SU spectrum has Swan bands of C 2 carbon molecules. Such stars are classified as class N according to the Harvard classification scheme; these are objects in which the blue part of the continuum is completely obscured by molecular absorption bands. Later, the spectral classes of carbon stars were updated in the Morgan-Kinan system, after which SU Andromedes are classified as C6 4 , [11] which means a relatively cold carbon star, index 4 shows the moderate intensity of the Swan band. [12]
In the framework of the modern revised Morgan-Kinan system, SU Andromeda are classified as C-N5 C 2 6-. [13] The CN spectral class distinguishes such stars from objects of the CR class, in which the continuum in the blue region is not completely overlapped by absorption bands. The classification based on the infrared spectrum assigns the star to class C5 II, again to the class of moderately cold stars of luminosity class II ( bright giant ). [6]
Companion Object
Andromeda SU is located 22 "from an object of magnitude 12.77, possibly a star of the main sequence of spectral class F0. According to the second release of Gaia data, the parallax of the star is 0.7479 ± 0.0905 [7] , and the absolute magnitude is +2.4 The motion in space of this object is the same as that of SU Andromeda.If we assume that the objects move together, the absolute magnitude of the SU Andromeda is −2.2. [5]
Notes
- ↑ 1 2 3 4 5 vizier.u-strasbg.fr .
- ↑ 1 2 3 4 SU And database entry . Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.) . CDS Date of appeal October 14, 2018.
- ↑ 1 2 Gontcharov G. A. Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system // Ast. Lett. / R. Sunyaev - Nauka , 2006 .-- Vol. 32, Iss. 11. - P. 759–771. - ISSN 1063-7737 ; 1562-6873 ; 0320-0108 ; 0360-0327 - doi: 10.1134 / S1063773706110065
- ↑ 1 2 3 4 5 Collaboration G. Gaia DR2 - 2018 .-- Vol. 1345.
- ↑ 1 2 Olson, BI; Richer, HB The absolute magnitudes of carbon stars - Carbon stars in binary systems (Eng.) // The Astrophysical Journal : journal. - IOP Publishing 1975. - Vol. 200 . - P. 88-94 . - DOI : 10.1086 / 153763 . - .
- ↑ 1 2 3 Richer, Harvey B. Some Intrinsic Properties of Carbon Stars (Eng.) // The Astrophysical Journal . - IOP Publishing 1971. - Vol. 167 . - P. 521-535 . - DOI : 10.1086 / 151049 . - .
- ↑ 1 2 3 4 vizier.u-strasbg.fr .
- ↑ 1 2 Bergeat, J .; Knapik, A .; Rutily, B. Carbon-rich giants in the HR diagram and their luminosity function ( Astronomy and Astrophysics : journal. - EDP Sciences , 2002. - Vol. 390 , no. 3 . - P. 967-986 . - DOI : 10.1051 / 0004-6361: 20020525 . - .
- ↑ Espin, TE Stars with remarkable spectra (unknown) // Astronomische Nachrichten. - 1895. - T. 137 , No. 22 . - S. 369—376 . - DOI : 10.1002 / asna.18951372202 . - .
- ↑ Pickering, EC; Fleming, WP Stars having peculiar spectra. Thirteen new variable stars // The Astrophysical Journal : journal. - IOP Publishing 1906. - Vol. 23 . - P. 257-261 . - DOI : 10.1086 / 141337 . - .
- ↑ Skiff, BA Catalog of Stellar Spectral Classifications (Skiff, 2009-2016 ) // VizieR On-line Data Catalog: B / mk: journal. - 2014. - .
- ↑ Keenan, Philip C .; Morgan, WW The Classification of the Red Carbon Stars (Eng.) // The Astrophysical Journal . - IOP Publishing 1941. - Vol. 94 . - P. 501-510 . - DOI : 10.1086 / 144356 . - .
- ↑ Barnbaum, Cecilia; Stone, Remington PS; Keenan, Philip C. A Moderate-Resolution Spectral Atlas of Carbon Stars: R, J, N, CH, and Barium Stars (Eng.) // The Astrophysical Journal : journal. - IOP Publishing 1996. - Vol. 105 . - P. 419—473 . - DOI : 10.1086 / 192323 . - .