HD 240429 and HD 240430

{{short description|Wide binary star system in the constellation Cassiopeia}}

{{Starbox begin}}

{{Starbox observe 2s

|epoch=J2000

|constell=Cassiopeia{{cite journal |bibcode=2012AstL...38..331A |title=XHIP: An extended hipparcos compilation |last1=Anderson |first1=E. |last2=Francis |first2=Ch. |journal=Astronomy Letters |date=2012 |volume=38 |issue=5 |page=331 |doi=10.1134/S1063773712050015 |arxiv=1108.4971 }}

|component1=HD 240429 (Krios)

|ra1={{RA|23|51|55.0287}}

|dec1={{DEC|+59|42|48.601}}

|appmag_v1=9.70{{cite journal|title=The Tycho-2 catalogue of the 2.5 million brightest stars|author=Høg, E.|display-authors=etal|date=2000|journal=Astronomy and Astrophysics|volume=355|pages=L27–L30|bibcode=2000A&A...355L..27H}}

|component2=HD 240430 (Kronos)

|ra2={{RA|23|52|09.2434}}

|dec2={{DEC|+59|42|26.521}}

|appmag_v2=9.56

}}

{{Starbox character

|component1=HD 240429

|class=G0

|component2=HD 240430

|class2=G2

}}

{{Starbox astrometry

|component1=HD 240429

|radial_v=−21.2

|prop_mo_ra=89.332

|prop_mo_dec=−29.319

|dist_ly=

|dist_pc=

|parallax=9.7559

|p_error=0.0111

|parallax_footnote={{cite Gaia DR3|1999551612692096128}}

|component2=HD 240430

|radial_v2=−21.2

|prop_mo_ra2=89.949

|prop_mo_dec2=−29.373

|dist_ly2=

|dist_pc2=

|parallax2=9.7353

|p_error2=0.0109

|parallax_footnote2={{cite Gaia DR3|1999550886837136640}}

}}

{{Starbox detail

|source=

|component1=HD 240429

|temperature=5878 ± 25

|gravity=4.43 ± 0.028

|rotational_velocity=1.1

|metal_fe=0.01 ± 0.010

|age_gyr={{val|4.00|+1.51|-1.56}}

|component2=HD 240430

|temperature2=5803 ± 25

|gravity2=4.33 ± 0.028

|rotational_velocity2=2.5

|metal_fe2=0.20 ± 0.010

|age_gyr2={{val|4.28|+1.11|-1.03}}

}}

{{Starbox catalog

|component1=HD 240429

|names1={{odlist|BD=+58°2662|SAO=35851}}{{cite simbad|title=HD 240429|access-date=30 April 2018}}

|component2=HD 240430

|names2={{odlist|BD=+58°2663|SAO=35854}}{{cite simbad|title=HD 240430|access-date=30 April 2018}}

}}

{{Starbox reference

|Simbad=HD+240429|sn=HD 240429

|Simbad2=HD+240430|sn2=HD 240430

}}

{{Starbox end}}

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.{{cite journal |last1=Semyeong |first1=Oh |last2=Price-Whelan |first2=Adrian M. |last3=Brewer |first3=John M. |last4=Hogg |first4=David W. |last5=Spergel |first5=David N. |last6=Myles |first6=Justin |title=Kronos and Krios: Evidence for Accretion of a Massive, Rocky Planetary System in a Comoving Pair of Solar-type Stars |journal=The Astrophysical Journal |arxiv=1709.05344 |date=2017 |volume=854 |issue=2 |page=138 |doi=10.3847/1538-4357/aaab4d |s2cid=119076217 |doi-access=free }} 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.{{cite news |last1=Princeton University |title=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 |url=https://www.sciencedaily.com/releases/2017/10/171012122832.htm |access-date=15 October 2017 |work=ScienceDaily |date=12 October 2017 }} Its unusual properties were described by a team of astrophysicists at Princeton University in 2017, led by Semyeong Oh.{{cite news |last1=Sokol |first1=Josh |title=Star nicknamed Kronos after eating its own planetary children |url=https://www.newscientist.com/article/2148182-star-nicknamed-kronos-after-eating-its-own-planetary-children/ |access-date=15 October 2017 |work=New Scientist |date=21 September 2017 }}

Kronos and Krios are about 350 light years away from Earth.{{cite news |last1=Fuller-Wright |first1=Liz |title=Devourer of planets? Princeton researchers dub star 'Kronos' |url=https://www.princeton.edu/news/2017/10/12/devourer-planets-princeton-researchers-dub-star-kronos |access-date=15 October 2017 |agency=Princeton University |date=12 October 2017 }} 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. According to estimates, it might have absorbed at least 15 Earth masses.