HD 240429 (nicknamed Krios) and HD 240430 (Kronos) is a wide binary star system in the constellation of Cassiopeia. Both components of the system are yellow G-type main-sequence stars.[3] HD 240430 is a Sun-like star in appearance, but it seems to have eaten its own planets, for which it is given the nickname Kronos, after the Greek god and the leader of the first generation of Titans.[7] Its unusual properties were described by a team of astrophysicists at Princeton University in 2017, led by Semyeong Oh.[8]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cassiopeia |
| HD 240429 (Krios) | |
| Right ascension | 23h 51m 55.0285s[1] |
| Declination | +59° 42′ 48.613″[1] |
| Apparent magnitude (V) | 9.70[2] |
| HD 240430 (Kronos) | |
| Right ascension | 23h 52m 09.2427s[1] |
| Declination | +59° 42′ 26.526″[1] |
| Apparent magnitude (V) | 9.56[2] |
| Characteristics | |
| HD 240429 | |
| Spectral type | G0[3] |
| HD 240430 | |
| Spectral type | G2[3] |
| Astrometry | |
| HD 240429 | |
| Radial velocity (Rv) | −21.2[3] km/s |
| Proper motion (μ) | RA: 89.25[4] mas/yr Dec.: −29.68[4] mas/yr |
| Parallax (π) | 9.7004 ± 0.0250 mas[4] |
| Distance | 336.2 ± 0.9 ly (103.1 ± 0.3 pc) |
| HD 240430 | |
| Radial velocity (Rv) | −21.2[3] km/s |
| Proper motion (μ) | RA: 89.41[4] mas/yr Dec.: −30.12[4] mas/yr |
| Parallax (π) | 9.6884 ± 0.0257 mas[4] |
| Distance | 336.6 ± 0.9 ly (103.2 ± 0.3 pc) |
| Details[3] | |
| HD 240429 | |
| Surface gravity (log g) | 4.43 ± 0.028 cgs |
| Temperature | 5878 ± 25 K |
| Metallicity [Fe/H] | 0.01 ± 0.010 dex |
| Rotational velocity (v sin i) | 1.1 km/s |
| Age | 4.00+1.51 −1.56 Gyr |
| HD 240430 | |
| Surface gravity (log g) | 4.33 ± 0.028 cgs |
| Temperature | 5803 ± 25 K |
| Metallicity [Fe/H] | 0.20 ± 0.010 dex |
| Rotational velocity (v sin i) | 2.5 km/s |
| Age | 4.28+1.11 −1.03 Gyr |
| Other designations | |
| HD 240429: BD+58° 2662, HD 240429, SAO 35851[5] | |
| HD 240430: BD+58° 2663, HD 240430, SAO 35854[6] | |
| Database references | |
| SIMBAD | HD 240429 |
| HD 240430 | |
Kronos and Krios are about 350 light years away from Earth.[9] Formed around four billion years ago, they originated from the same interstellar cloud. They are moving together through space and are assumed to orbit each other slowly, with an estimated period of about 10,000 years. Kronos has a higher abundance of elements such as lithium, magnesium and iron in its atmosphere than in that of Krios. They are the most chemically different binary stars to have been discovered to date. The unusual and rich chemical composition leads scientists to the conclusion that Kronos has destroyed many of its orbiting planets.[8] According to estimates, it might have absorbed at least 15 Earth masses.[3]
See also
editReferences
edit- ^ a b c d Gaia Collaboration (2016). "Gaia Data Release 1". Astronomy & Astrophysics. 595: A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. S2CID 1828208.
- ^ a b Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ a b c d e f g Semyeong, Oh; Price-Whelan, Adrian M.; Brewer, John M.; Hogg, David W.; Spergel, David N.; Myles, Justin (2017). "Kronos and Krios: Evidence for Accretion of a Massive, Rocky Planetary System in a Comoving Pair of Solar-type Stars". The Astrophysical Journal. 854 (2): 138. arXiv:1709.05344. doi:10.3847/1538-4357/aaab4d. S2CID 119076217.
- ^ a b c d e f 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.
- ^ "HD 240429". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 April 2018.
- ^ "HD 240430". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 April 2018.
- ^ Princeton University (12 October 2017). "Devourer of planets? Astronomers dub star 'Kronos': Sun-like star Kronos shows signs of having consumed 15 Earth masses worth of rocky planets, prompting astronomers to name it after the Titan who ate his children". ScienceDaily. Retrieved 15 October 2017.
- ^ a b Sokol, Josh (21 September 2017). "Star nicknamed Kronos after eating its own planetary children". New Scientist. Retrieved 15 October 2017.
- ^ Fuller-Wright, Liz (12 October 2017). "Devourer of planets? Princeton researchers dub star 'Kronos'". Princeton University. Retrieved 15 October 2017.
External links
edit- "Kronos: Devourer Of Worlds". PBS Space Time. January 31, 2018 – via YouTube.