LP Andromedae
Star in the constellation Andromeda
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LP Andromedae (often abbreviated to LP And) is a carbon star in the constellation Andromeda. It is also a Mira variable[7] whose mean apparent visual magnitude is 15.12 and has pulsations with an amplitude of 1.50 magnitudes[3] and a period of 614 days.[8]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h 34m 27.5216s[2] |
| Declination | +43° 33′ 01.2996″[2] |
| Apparent magnitude (V) | 15.12 variable[3] |
| Characteristics | |
| Spectral type | C8,3.5e[4] |
| Apparent magnitude (G) | 16.9041[2] |
| Apparent magnitude (J) | 9.623[5] |
| Apparent magnitude (H) | 6.355[5] |
| Apparent magnitude (K) | 2.71[6] |
| Variable type | Mira[7] |
| Astrometry | |
| Proper motion (μ) | RA: −21.313±0.532 [2] mas/yr Dec.: −22.058±0.453[2] mas/yr |
| Parallax (π) | 2.5002±0.3626 mas[2] |
| Distance | approx. 1,300 ly (approx. 400 pc) |
| Absolute bolometric magnitude (Mbol) | −5.21±0.26[8] |
| Details[8] | |
| Mass | 0.8 M☉ |
| Radius | 340 – 420 R☉ |
| Luminosity | 2,900 – 16,200 L☉ |
| Temperature | 2,100 – 3,350 K |
| Other designations | |
| 2MASS J23342752+4333012, IRAS 23320+4316, RAFGL 3116 | |
| Database references | |
| SIMBAD | data |
In 1974 LP Andromedae, known then as IRC+40540, was identified as a carbon star and also shown to be variable.[9] It had previously been suspected of variability during the 2 Micron All Sky Survey (2MASS). A detailed study of its spectrum showed an unusually cool star with a basic class of C8, and Swan band strength of 3.5. It also showed strong C13 isotopic bands.[4] The period was narrowed down to around 614 days, one of the longest periods known for a Mira variable.[10]
This star has a dusty envelope with an estimated mass of 3.2 M☉, fueled by the star itself which is losing mass at a rate 1.9×10−5 M☉/yr. Such a high mass loss rate should place LP Andromedae close to the end of its asymptotic giant branch evolution. The envelope extends to a distance of 3 parsec from the star, and is mainly made of silicon carbide and carbon particles.[8]