MY Apodis
 A light curve for MY Apodis, plotted from TESS data.[1] Approximately 400 raw data points were averaged to produce each plotted point. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus |
| Right ascension | 14h 33m 07.636s[2] |
| Declination | −81° 20′ 14.13″[2] |
| Apparent magnitude (V) | 13.75[3] |
| Characteristics | |
| Evolutionary stage | Compact star |
| Spectral type | DA4.1[3] |
| U−B color index | −0.530 |
| B−V color index | 0.25 |
| Variable type | ZZ Cet[3][4] |
| Astrometry | |
| Radial velocity (Rv) | 58.0[5] km/s |
| Proper motion (μ) | RA: −154.665 mas/yr[2] Dec.: −389.971 mas/yr[2] |
| Parallax (π) | 47.7874±0.0295 mas |
| Distance | 68.25 ± 0.04 ly (20.93 ± 0.01 pc) |
| Absolute magnitude (MV) | 11.86[3] |
| Details | |
| Mass | 0.705±0.023[6] M☉ |
| Radius | 0.011±0.001[6] R☉ |
| Luminosity | 0.00347[7] L☉ |
| Surface gravity (log g) | 8.17±0.04[3] cgs |
| Temperature | 12,330±182[3] K |
| Rotation | 13 h[8] |
| Other designations | |
| MY Aps, GJ 2108, L 19-2, LTT 5712, WD 1425-81, 1425-811[9] | |
| Database references | |
| SIMBAD | data |
MY Apodis, also known as L 19-2, GJ 2108, or WD 1425-811, is a single[7] white dwarf star located in the far southern constellation Apus. It is a low-amplitude variable star[10] with an average apparent visual magnitude of 13.75[3] and thus is much too faint to be visible to the naked eye. Based on parallax measurements, this star is located at a distance of 68.3 light-years from the Sun. It is drifting further away with a radial velocity of 58.0[5]
This compact stellar remnant has a class of DA4.1,[3] which indicates a hydrogen-rich outer atmosphere. It is a pulsating white dwarf (ZZ Ceti star) that varies photometrically with an amplitude of 0.05 in visual magnitude.[4] The low-amplitude variability of this ZZ Ceti analog was discovered by James E. Hesser and associates in 1974, who found it showed periods of 192.75±0.1 and 113.77±0.1 seconds.[10] By 2015, ten different pulsation modes had been identified, and it remained stable over four decades of observation.[11]
MY Apodis has 70.5%[6] of the mass of the Sun compressed down into 1.1%[6] of the Sun's radius. It is spinning rapidly with a rotation period of 13 hours.[8] The star is radiating just 0.35%[7] of the luminosity of the Sun at an effective temperature of 12,330 K.[3] Astroseismological models suggest the star has a thin outer hydrogen shell with a mass of 1.0×10−4 M☉, an intermediate helium layer of 1.5 to 2.0×10−2 M☉, and a core of 20% carbon and 80% oxygen that extends out to 60% of the stellar radius.[8]
References
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- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
- ^ a b c d e f g h i Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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- ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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