Free Astronomy Magazine September-October 2026 ARABIC VERSION

49 nificantly warmer than expected and determined how it most likely reached its very tight orbit around the white dwarf star. The results, publishedinthejournal Nature ,are awindowintothefutureofplanets like Jupiter after the death of the Sun,billionsofyearsintothefuture. WD 1856 b was discovered in 2020 by scientists using NASA's TESS (TransitingExoplanetSurveySatel- lite) and Spitzer space telescopes. It orbitsthewhitedwarfWD1856 +534, which is located about 80light- years from Earth. “The planet is about the size of Jupiter,butthewhitedwarfitorbits is the size of Earth, so the planet is seventimeslargerthanitsstar,” said lead author Ryan MacDonald of the University of St. Andrews in the United Kingdom. WD 1856 b orbits extremely close toitshoststar,adistance50times closer than Earth orbits the Sun. If WD 1856 b had originally been or- biting at that distance, it would havebeenobliteratedwhilethestar was a red giant. How did it survive thedeathofitshoststarandendup in its current position? ThenewstudyusedWebbtowatch theplanetpassinginfrontofitsstar. Thistransityieldeduniqueinforma- tionabouttheplanet’smass,which is between four and eleven times the mass of Jupiter. Theteamalsowasabletodetermine the planet’s temperature. During the transit, light from the star was partly blocked, but infrared light was reduced less than other wave- lengths. The difference was infrared lightemittedbytheplanetfromits own heat. The data indicated that the planet has a temperature of about 260 degrees Fahrenheit (126 degreesCelsius)—significantlyhot- terthanitwouldbeifitsonlysource ofheatwasthelightfromthewhite dwarf. This puzzling discovery turned out to be the key fact that proved how the planet must have reached its current orbit. Christopher O’Connor of North- westernUniversityinIllinois,aco- author on the paper, was responsi- ble for tracing the temperature of the planet back in time. O’Connor said, “The big question is how WD 1856 b ended up where it is today, and there are two theories. One is that the planet was swallowed by the host star as it was dying, and managed to survive on the inside. The other is that migration took place due to the gravitational ef- fect of other objects in the system. The white dwarf is part of a triple star system, and the companionstarscouldhaveinfluenced WD 1856 b’s orbit.” Theresearchersrealizedthatthere was no source of energy present to generatethatheattoday,soitmust be residual energy from an earlier time when the planet was heated. Usingmodelsofhowsub-stellarob- jectslikeWD1856bcooldownover time, coupled with the new data from Webb, the team was able to project its temperature back in time anddeducehowlongagotheheat- ingmusthavehappened.Thetiming SEPTEMBER-OCTOBER2026 ﻟﻠﻐﺎﻳﺔ ﺣﻮل اﻟﻘﺰم اﻷﺑﻴﺾ وﻗﺪ ﻧ ﴩت اﻟﻨﺘﺎﺋﺞ ﰲ ﻣﺠﻠـﺔ ﻧﻴــﺘﴩ وﻫـﻲ ﺗﻤﺜـﻞ ﻧﺎﻓـﺬة ﻋـﲆ ﻣﺴﺘﻘﺒﻞ ﻛﻮاﻛﺐ ﻣﺜـﻞ ا ﺸـﱰي ﺑﻌـﺪ ﻣـﻮت اﻟﺸــﻤﺲ ﺑﻌـﺪ ﻣﻠﻴـﺎرات اﻟﺴـﻨ ﻣـﻦ اﻵن . اﻛﺘُﺸـﻒ اﻟﻜﻮﻛـﺐ WD 1856 b ﻋـﺎم 2020 ﺑﺎﺳـﺘﺨﺪا م اﻟﻘﻤــﺮﻳﻦ اﻟﺼــﻨﺎﻋﻴ ﺗﻴﺴــﺲ وﺳﺒﻴﺘﺰر اﻟﺘﺎﺑﻌ ﻟ ﻮﻛﺎﻟﺔ ﻧﺎﺳـﺎ وﻫـﻮ ﻳـﺪور ﺣﻮل اﻟﻘﺰم اﻷﺑـﻴﺾ WD 1856+534 اﻟـﺬي ﻳﻘﻊ ﻋﲆ ﺑﻌـﺪ ﻧﺤـﻮ 80 ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ ﻣـﻦ اﻷرض . ﻗﺎل ا ﺆﻟﻒ اﻟﺮﺋﻴﴘ ﻟﻠﺪراﺳـﺔ رﻳـﺎن ﻣﺎﻛﺪوﻧﺎﻟـﺪ ﻣـﻦ ﺟﺎﻣﻌـﺔ ﺳـﺎﻧﺖ أﻧـﺪروز ﰲ ا ﻤﻠﻜـﺔ ا ﺘﺤـﺪة :» اﻟﻜﻮﻛـﺐ ﻳﻘـﺎرب ﺣﺠــﻢ ا ﺸﱰي ﺑﻴﻨﻤﺎ اﻟﻘﺰم ا ﻷﺑﻴﺾ اﻟﺬي ﻳﺪور ﺣﻮﻟﻪ ﺑﺤﺠﻢ اﻷرض وﻟﺬﻟﻚ ﻓﺈن اﻟ ﻜﻮﻛﺐ أﻛـﱪ ﻣـﻦ ﻧﺠﻤﻪ ﺑﻨﺤﻮ ﺳﺒﻊ ﻣﺮات « وﻳﺪور WD 1856 b ﻋﲆ ﻣﺴﺎﻓﺔ ﻗﺮﻳﺒﺔ ﺟـﺪاً ﻣـﻦ ﻧﺠﻤـﻪ ﺗﻌـﺎدل ﺧﻤﺴ ﻣﺮة أ ﻗﺮب ﻣﻦ ا ﺴـﺎﻓﺔ ﺑـ اﻷرض واﻟﺸﻤﺲ وﻟﻮ ﻛﺎن اﻟﻜﻮﻛﺐ ﻳﺪور أﺻـﻼً ﻋـ ﲆ ﻫﺬه ا ﺴﺎﻓﺔ ﻟﻜﺎن ﻗﺪ دﻣـ ﺮ ﺑﺎﻟﻜﺎﻣـﻞ ﻋﻨـﺪﻣﺎ ﺗﺤﻮل اﻟﻨﺠﻢ إﱃ ﻋﻤﻼق أﺣﻤﺮ . ﻓﻜﻴﻒ ﻧﺠﺎ ﻣﻦ ﻣﻮت ﻧﺠﻤﻪ ا ﻀﻴﻒ ووﺻﻞ إﱃ ﻣﻮﻗﻌﻪ اﻟﺤﺎﱄ؟ اﻋﺘﻤﺪت اﻟﺪراﺳﺔ اﻟﺠﺪﻳﺪة ﻋﲆ ﻣﺮاﻗﺒﺔ ﺗﻠﺴﻜﻮب و ﻳﺐ ﻟﻠﻜﻮﻛﺐ أﺛﻨﺎء ﻣـﺮوره أﻣﺎم ﻧﺠﻤﻪ وأﺗﺎح ﻫﺬا اﻟﻌﺒﻮر اﻟﺤﺼـﻮل ﻋـﲆ ﻣﻌﻠﻮﻣﺎت ﻓﺮﻳﺪة ﻋـﻦ ﻛﺘﻠـﺔ اﻟﻜﻮﻛـﺐ، اﻟﺘـﻲ اﻟ ﻮﻛــﺐ ـ اﻟــ ﺨﺎرﺟﻲ WD 1856 b اﻟﻤﻮﺿــﺢ ﻓــﻲﻫــﺬا اﻟﺮﺳــﻢ اﻟﺘﺨ ﻠـﻲ ﻫــ ﻮ ﻋﻤــﻼق ﻏــﺎزي ﻧﺠــﺎ ﻣــﻦ ﻣــﻮت ﻧ ﻤﮫ . ﺪور اﻵن ﺣـﻮل ﻗـﺰم أﺑـ ﺾﻋﻠـﻰﻣﺴـﺎﻓﺔ 50 ﺿـﻌﻔﺎً أﻗـﺮ ﻣـﻦ ﻣـﺪار اﻷرضﺣـﻮل اﻟﺸـﻤﺲ . ﻟـﻢ ﺗﻘﺘﺼـﺮ أرﺻﺎد ﺗﻠﺴ ﻮبﺟ ﻤﺲو ﺐ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ ﻋﻠﻰ ﺗﺤﺪ ﺪ درﺟﺔ ﺣﺮارة اﻟ ﻮﻛﺐ ﻓﺤﺴﺐ ﺑﻞ رﺻﺪت أ ﻀﺎً ﺟﺰ ﺌﺎت ﻓﻲﻏﻼﻓﮫ اﻟ ـ . ﺠﻮي ﻘﺪمﻫﺬا اﻟﻘ ﺎسدﻟ ﻼً ﻋﻠﻰ أن WD 1856 b ﻫﺎﺟﺮ إﻟﻰﻣﻮﻗﻌـﮫ اﻟـ ـ ﺤﺎﻟﻲ ﻌـﺪ ﻣﻦ ﺗﺤﻮل ﻧ ﻤﮫ إﻟﻰﻗﺰم أﺑ ﺾ ﻣﻠ ﺎرات اﻟﺴﻨ . [Artwork: NASA, ESA, CSA, Ralf Crawford (STScI)] ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 49 ﻣﻌﻠﻮﻣﺎت ﻓﺮﻳـﺪة ﻋـﻦ ﻛﺘﻠـﺔ اﻟﻜﻮﻛـﺐ اﻟﺘـﻲ ﺗﱰاوح ﺑ أرﺑﻌﺔ وأﺣﺪ ﻋ ـ ﴩ ﺿـﻌﻒ ﻛﺘﻠـﺔ ا ﺸﱰي ﻛﻤﺎ ﺗﻤﻜﻦ اﻟﻔﺮﻳﻖ ﻣﻦ ﺗﺤﺪﻳﺪ درﺟـﺔ ﺣﺮارة اﻟﻜﻮﻛﺐ . وﺧﻼل اﻟﻌﺒﻮر ﺣﺠـﺐ ﺟـﺰء ﻣﻦ ﺿﻮء اﻟﻨﺠﻢ ﻟﻜﻦ اﻧﺨﻔﺎض اﻷﺷﻌﺔ ﺗﺤـﺖ اﻟﺤﻤﺮاء ﻛﺎن أﻗﻞ ﻣﻦ ﺑﻘﻴﺔ اﻷﻃـﻮال ا ﻮﺟﻴـﺔ اً ﻷن ﺟﺰء ﻣﻨﻬﺎ ﻛﺎن ﺻﺎدر اً ﻋﻦ ﺣﺮارة اﻟﻜﻮﻛﺐ ﻧﻔﺴﻪ . وأﻇﻬﺮت اﻟﺒﻴﺎﻧـﺎت أن درﺟـﺔ ﺣـﺮارة اﻟﻜﻮﻛﺐ ﺗﺒﻠﻎ ﻧﺤـﻮ 260 درﺟـﺔ ﻓﻬﺮﻧﻬﺎﻳـﺖ ) 126 درﺟﺔ ﻣﺌﻮﻳﺔ ( وﻫﻲ أﻋـﲆ ﺑﻜﺜـ ﻣﻤـﺎ ﻳ ﺘﻮﻗﻊ ﻟﻮ ﻛﺎن ﻣﺼﺪر ﺣﺮار ﺗـﻪ اﻟﻮﺣﻴـﺪ ﻫـﻮ إﺷ ـﻌﺎع اﻟﻘــﺰم اﻷﺑ ـﻴﺾ واﺗﻀ ـﺢ أن ﻫــﺬا اﻻﻛﺘﺸﺎف ا ﺤ ﻫﻮ ا ﻔﺘـﺎح ﻟﻔﻬـﻢ ﻛﻴﻔﻴـﺔ وﺻﻮل اﻟﻜﻮﻛﺐ إﱃ ﻣﺪاره اﻟﺤﺎﱄ . ﻗﺎل ﻛﺮﻳﺴﺘﻮﻓﺮ أوﻛﻮﻧﻮر ﻣﻦ ﺟﺎﻣﻌـﺔ ﻧـﻮرث وﺳﱰن ﰲ وﻻﻳﺔ إﻟﻴﻨـﻮي وﻫـﻮ أﺣـﺪ ﻣـﺆﻟﻔﻲ اﻟﺪراﺳﺔ وا ﺴﺆول ﻋﻦ ﺗﺘﺒﻊ اﻟﺘﺎرﻳﺦ اﻟﺤﺮاري ﻟﻠﻜﻮﻛﺐ :» اﻟﺴﺆال اﻟﻜﺒ ﻫـﻮ : ﻛﻴـﻒ وﺻـﻞ WD 1856 b إﱃ ﻣﻮﻗﻌــﻪ اﻟﺤــﺎﱄ؟ ﻫﻨــﺎك ﻓﺮﺿﻴﺘﺎن اﻷوﱃ أن اﻟﻜﻮﻛﺐ اﺑﺘﻠﻌﻪ اﻟﻨﺠﻢ أﺛﻨﺎء اﺣﺘﻀﺎره وﺗﻤﻜﻦ ﺑﻄﺮﻳﻘﺔ ﻣﺎ ﻣﻦ اﻟﻨﺠﺎة ﻣـﻦ . داﺧﻠﻪ أﻣﺎ اﻟﺜﺎﻧﻴﺔ ﻓﻬﻲ أن اﻟﻜﻮﻛﺐ ﻫﺎﺟﺮ إﱃ اﻟﺪاﺧﻞ ﻧﺘﻴﺠـﺔ اﻟﺘـﺄﺛ ات اﻟﺠﺎذﺑﻴـﺔ ﻷﺟـﺮام أﺧﺮى ﰲ اﻟﻨﻈﺎم « وأﺿﺎف أن اﻟﻘـﺰم اﻷﺑـﻴﺾ ﻋﻀﻮ ﰲ ﻧﻈﺎم ﻧ ﺠﻤـﻲ ﺛﻼﺛـﻲ، ورﺑﻤـﺎ أﺛـﺮت ﻋﻀﻮ ﰲ ﻧﻈﺎم ﻧﺠﻤـﻲ ﺛﻼﺛـﻲ ورﺑﻤـﺎ أﺛـﺮت اﻟﻨﺠﻮم ا ﺮاﻓﻘﺔ ﰲ ﻣﺪار اﻟﻜﻮﻛﺐ . أدرك اﻟﺒﺎﺣﺜﻮن أﻧـﻪ ﻻ ﻳﻮﺟـﺪ اﻟﻴـﻮم ﻣﺼـﺪر ﻟﻠﻄﺎﻗﺔ ﻳﻤﻜﻦ أن ﻳﻮﻟﺪ ﻫﺬه اﻟﺤﺮارة ﻣﻤﺎ ﻳﻌﻨﻲ أﻧﻬﺎ ﺣﺮارة ﻣﺘﺒﻘﻴﺔ ﻣﻦ ﻓﱰة ﺳﺎﺑﻘ ﺔ ﺗﻌـﺮض ﻓﻴﻬﺎ اﻟﻜﻮﻛﺐ ﻟﻌﻤﻠﻴـﺔ ﺗﺴـﺨ وﺑﺎﺳـﺘﺨﺪام ﻧﻤـﺎذج ﺗﺼـﻒ ﻛﻴﻔﻴــﺔ ﺗﱪﻳـﺪ اﻷﺟـﺮام دون اﻟﻨﺠﻤﻴﺔ ﻣﺜﻞ اﻟﻜﻮﻛﺐ WD 1856 b ﻣﻊ ﻣﺮور اﻟــﺰﻣﻦ إﱃ ﺟﺎﻧـﺐ ﺑﻴﺎﻧـﺎت ﺗﻠﺴـﻜﻮب وﻳـﺐ اﻟﺠﺪﻳﺪة ﺗﻤﻜﻦ اﻟﻔﺮﻳـﻖ ﻣـﻦ إﻋـﺎدة ﺣﺴـﺎب درﺟﺔ ﺣﺮارة اﻟﻜﻮﻛـﺐ ﰲ ا ـﺎﴈ واﺳـﺘﻨﺘﺎج اﻟﺰﻣﻦ اﻟﺬ ي ﺣﺪث ﻓﻴﻪ ﻫﺬا اﻟﺘﺴـﺨ . وﻛـﺎن ﺗﻮﻗﻴﺖ ﻫﺬا اﻟﺤﺪث ﻫـﻮ اﻟـ ـ ﻌﻨﴫ اﻟﺤﺎﺳـﻢ ﻌﺮﻓﺔ ﻣﺎ إذا ﻛﺎﻧﺖ اﻟﺤﺮارة ﻧﺎﺗﺠﺔ ﻋﻦ اﺑ ﺘﻼع اﻟﻜﻮﻛﺐ داﺧﻞ اﻟﻌﻤﻼق اﻷﺣﻤﺮ أم ﻋﻦ اﻧﺘﻘﺎﻟﻪ ﻻﺣﻘًﺎ إﱃ ﻣﺪار أﻗﺮب . وﺧﻠﺺ اﻟﺒﺎﺣﺜﻮن إﱃ أن ﻋﻤﻠﻴﺔ اﻟﺘﺴﺨ ﺣﺪﺛﺖ ﻋﲆ اﻷرﺟﺢ ﺑﻌﺪ 3 إﱃ 5.5 ﻣﻠﻴﺎرات ﺳﻨﺔ ﻣﻦ ﺗﺤﻮل اﻟـﻨ ﺠﻢ إﱃ ﻗـﺰم أﺑﻴﺾ وﰲ ﻫﺬا اﻟﺴﻴﻨﺎ رﻳﻮ ﻛﺎن اﻟﻜﻮﻛﺐ ﻳـﺪور ﰲ اﻟﺒﺪاﻳﺔ ﰲ ﻣﺪار واﺳـﻊ أﺑﻘـﺎه ﺑﻤﻨـﺄى ﻋـﻦ اﻟﻨﺠﻢ ﺧﻼل ﻣﺮﺣﻠﺔ اﻟﻌﻤﻼق اﻷﺣﻤﺮ ا ـﺪﻣﺮة، ﺛﻢ ﻫﺎﺟﺮ إﱃ ﻣﻮﻗﻌﻪ اﻟﺤـﺎﱄ ﰲ وﻗـﺖ ﻻﺣـﻖ . وﻗـﺎل أوﻛﻮﻧـﻮ »: ر ﻣـﻊ اﻧﺘﻘـﺎل اﻟﻜﻮﻛـﺐ إﱃ اﻟﺪاﺧﻞ أدت ﺗﻔﺎﻋﻼﺗﻪ ﻣﻊ اﻟﺠﺎذﺑﻴـﺔ اﻟﻘﻮﻳـﺔ ـــــــــــــ ــــــــــــــــــــــــ - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 6