R Andromedae
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Star R Andromedae |
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| AladinLite | |||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Andromeda | ||||||||||||||||
| Right ascension | 00 h 24 m 1.95 s | ||||||||||||||||
| declination | + 38 ° 34 ′ 37.4 ″ | ||||||||||||||||
| Apparent brightness | 5.8 - 15.2 mag | ||||||||||||||||
| Typing | |||||||||||||||||
| B − V color index | 1.97 | ||||||||||||||||
| U − B color index | 1.25 | ||||||||||||||||
| R − I index | 2.15 | ||||||||||||||||
| Spectral class | S3,5e-S8,8e (M7e) | ||||||||||||||||
| Variable star type | M. | ||||||||||||||||
| Astrometry | |||||||||||||||||
| Radial velocity | (−6.4 ± 0.7) km / s | ||||||||||||||||
| parallax | (4.13 ± 0.46) mas | ||||||||||||||||
| distance | (790) ly (240) pc |
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| Proper movement | |||||||||||||||||
| Rec. Share: | (−17.24 ± 0.49) mas / a | ||||||||||||||||
| Dec. portion: | (−30.07 ± 0.46) mas / a | ||||||||||||||||
| Physical Properties | |||||||||||||||||
| radius | (485 ± 124) R ☉ | ||||||||||||||||
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Other names and catalog entries |
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R Andromedae (short R And ) is a long-period variable star of the Mira type in the constellation Andromeda . Its apparent brightness fluctuates with a period of 409.2 days and a very large amplitude between a maximum value of 5.8 mag, where it is visible to the naked eye, and a minimum value of 15.2 mag, where it can only be detected with the help of a 25 -cm telescope is recognizable. It belongs to the spectral class S and its spectrum shows absorption bands of zirconium oxide. The American astronomer Paul Willard Merrill found absorption lines of the radioactive element technetium in him (and also other stars) , with which he proved that nucleosynthesis must take place in stars .
Individual evidence
- ↑ a b c d e f g SIMBAD : R And. Retrieved July 8, 2018 .
- ↑ a b R And , in: NN Samus, .O V. Durlevich, et al. (2009). "VizieR Online Data Catalog: General Catalog of Variable Stars (Samus + 2007-2013)".
- ↑ R and. In: VSX. AAVSO , accessed July 8, 2018 .
- ^ GT van Belle, HM Dyck, RR Thompson, JA Benson, SJ Kannappan: Angular Size Measurements of Carbon Miras and S-Type Stars . In: The Astronomical Journal . 114, No. 5, 1997, pp. 2150-2156. bibcode : 1997AJ .... 114.2150V . doi : 10.1086 / 118635 .
- ↑ John Sanford: The new cosmos star atlas . English original edition London 1989, German Stuttgart 1990, ISBN 3-440-06087-X , p. 12.
- ^ PW Merrill: Technetium in the stars . In: Science . 115, 1952, pp. 479-489 [484]. bibcode : 1952Sci ... 115..479. . doi : 10.1126 / science.115.2992.479 .