{"id":213615,"date":"2022-10-02T10:52:58","date_gmt":"2022-10-02T08:52:58","guid":{"rendered":"https:\/\/osr.org\/?p=213615"},"modified":"2024-05-24T22:41:04","modified_gmt":"2024-05-24T20:41:04","slug":"evrendeki-bilinen-en-buyuk-yildiz-hangisi","status":"publish","type":"post","link":"https:\/\/osr.org\/tr\/blog\/ipuclari-ve-hediyeler\/evrendeki-bilinen-en-buyuk-yildiz-hangisi\/","title":{"rendered":"Evrendeki bilinen en b\u00fcy\u00fck y\u0131ld\u0131z hangisi?"},"content":{"rendered":"
Mesele y\u0131ld\u0131zlara gelindi\u011finde, g\u00fcne\u015fimiz t\u00fcm dikkatleri \u00fczerine \u00e7eker. D\u00fcnya\u2019da s\u00fcren ya\u015fam yaln\u0131zca kelimenin ger\u00e7ek anlam\u0131yla onun y\u00f6r\u00fcngesinde d\u00f6nmekle kalmaz, o ayn\u0131 zamanda g\u00f6ky\u00fcz\u00fcndeki y\u0131ld\u0131zlar\u0131n geri kalan\u0131n\u0131 da \u00e7ok k\u00fc\u00e7\u00fck g\u00f6sterir; en az\u0131ndan bizim bak\u0131\u015f a\u00e7\u0131m\u0131zdan. Buna kar\u015f\u0131n, galaksimizin uzak k\u00f6\u015felerine do\u011fru gitti\u011finizde, G\u00fcne\u015f art\u0131k \u00f6yle devasa g\u00f6r\u00fcnmez. Asl\u0131nda, boyutlar\u0131 itibariyle fazlas\u0131yla ortalama bir y\u0131ld\u0131zd\u0131r. O halde, evrendeki bilinen en b\u00fcy\u00fck y\u0131ld\u0131z hangisidir?<\/p>\n
Arizona eyaletinin Flagstaff kentinde bulunan Lowell G\u00f6zlemevi\u2019nde bir astronom olan Phil Massey yan\u0131t olarak, \u201cBu, k\u00fctleden mi yoksa bir y\u0131ld\u0131z\u0131n toplam hacminden mi bahsetti\u011finize, yani ne kadar yer kaplad\u0131\u011f\u0131na ba\u011fl\u0131\u201d diyor. Fiziksel boyut s\u00f6z konusuysa, genellikle en a\u011f\u0131r y\u0131ld\u0131zlar dikkat \u00e7ekicidir ve en hacimli y\u0131ld\u0131zlar \u00e7o\u011fu zaman en hafif olanlard\u0131r. Zira, y\u0131ld\u0131zlar ya\u015fland\u0131k\u00e7a, geni\u015flemeye ve k\u00fctle kaybetmeye e\u011filimlidirler. Massey, \u201cT\u0131pk\u0131 insanlardan bahsetmek gibi. En uzun boya sahip olan insanlar en fazla a\u011f\u0131rl\u0131\u011fa sahip olmayabilir\u201d diyor.<\/p>\n<\/div>\n
Diyelim ki k\u00fctleden bahsediyorsunuz. Massey, bu alandaki rekor sahibinin, \u2018R136a1\u2019 ad\u0131 verilen bir y\u0131ld\u0131z oldu\u011funu aktar\u0131yor. Samanyolu\u2019nun y\u00f6r\u00fcngesinde d\u00f6nen k\u00fc\u00e7\u00fck bir galaksi olan B\u00fcy\u00fck Macellan Bulutu\u2019nda, D\u00fcnya\u2019dan yakla\u015f\u0131k 160 bin \u0131\u015f\u0131ky\u0131l\u0131 mesafede bulunuyor. Bu y\u0131ld\u0131z \u00e7ap olarak, g\u00fcne\u015fimizin 30 il\u00e2 40 kat\u0131 b\u00fcy\u00fckl\u00fc\u011f\u00fcnde; g\u00f6z\u00fcn\u00fcz\u00fcn \u00f6n\u00fcne di\u011ferinden 200 kattan daha b\u00fcy\u00fck olan dev bir pilates topunun yan\u0131nda duran bir kiraz\u0131 getirin. Bu y\u0131ld\u0131z ayn\u0131 zamanda nispeten gen\u00e7 -g\u00fcne\u015fimizin 4.5 milyar y\u0131l\u0131na k\u0131yasla a\u015fa\u011f\u0131 yukar\u0131 1 milyon ya\u015f\u0131nda- ve Massey\u2019in aktard\u0131\u011f\u0131 kadar\u0131yla \u201c\u00e7ok fazla so\u011fuma ya da geni\u015fleme sergilemiyor\u201d.<\/p>\n
Massey, evrendeki (bilinen) en b\u00fcy\u00fck y\u0131ld\u0131z\u0131n en b\u00fcy\u00fck \u00e7apa sahip y\u0131ld\u0131z olmas\u0131 halinde, bir grup yar\u0131\u015fmac\u0131n\u0131n s\u00f6z konusu olaca\u011f\u0131n\u0131 s\u00f6yl\u00fcyor. Listenin en \u00fcst\u00fcnde UY Scuti bulunuyor. Astronomy and Astrophysics dergisinde 2013 y\u0131l\u0131nda yay\u0131nlanan bir ara\u015ft\u0131rmaya g\u00f6re, bu k\u0131rm\u0131z\u0131 hiper-devin \u00e7ap\u0131, G\u00fcne\u015f\u2019in neredeyse 1700 kat\u0131. \u015eayet G\u00fcne\u015f bir kiraz tanesi olsayd\u0131, UY Scuti 10 katl\u0131 bir k\u00fcre olurdu. Bununla birlikte, \u00e7ok uzaklardaki y\u0131ld\u0131zlar\u0131n \u00e7ap\u0131n\u0131 tespit etme hususunda pek \u00e7ok belirsizlik mevcut (ve UY Scuti, 1000 \u0131\u015f\u0131ky\u0131l\u0131 az ya da \u00e7ok olmak \u00fczere, D\u00fcnya\u2019dan yakla\u015f\u0131k 9 bin 500 \u0131\u015f\u0131ky\u0131l\u0131 mesafede bulunuyor). Bunu yapabilmeleri i\u00e7in, bilim insanlar\u0131n\u0131n y\u0131ld\u0131z\u0131n ne kadar \u0131\u015f\u0131k \u00fcretti\u011fini bilmeleri gerekir; bahsi ge\u00e7en, y\u0131ld\u0131zlar\u0131n (azalan ya da \u00e7o\u011falan) mesafe nedeniyle daha s\u00f6n\u00fck ya da daha parlak g\u00f6r\u00fcnmesi y\u00fcz\u00fcnden g\u00fcvenilmez bir rakamd\u0131r. Massey, UY Scuti benzeri k\u0131rm\u0131z\u0131 hiper-devlerin, \u00e7o\u011fu zaman \u201cde\u011fi\u015fken\u201d oldu\u011funu, yani parlakl\u0131klar\u0131n\u0131n zaman i\u00e7inde azald\u0131\u011f\u0131n\u0131 veya artt\u0131\u011f\u0131n\u0131 ve [\u00f6l\u00e7\u00fcmlerin] b\u00fcy\u00fck bir hata pay\u0131 ile neticelendi\u011fi ger\u00e7e\u011fini de s\u00f6zlerine ekliyor.<\/p>\n
\u00d6rnek olarak, 2013 tarihli makalenin yazarlar\u0131, UY Scuti\u2019nin yakla\u015f\u0131k 192 G\u00fcne\u015f yar\u0131\u00e7ap\u0131 oran\u0131nda, tahmin edilenden daha b\u00fcy\u00fck ya da k\u00fc\u00e7\u00fck olabilece\u011fini belirtiyor. Massey, \u201cK\u0131rm\u0131z\u0131 hiper-devler a\u015f\u0131r\u0131 da\u011f\u0131n\u0131klar ve bu nedenle modellenmeleri zor\u201d diyor: \u201cY\u00fczeyleri s\u00fcrekli bi\u00e7imde hareket halinde.\u201d<\/p>\n
Benzer \u015fekilde, di\u011fer iri y\u0131ld\u0131zlar aras\u0131nda, Massey\u2019in, her ikisinin de G\u00fcne\u015f\u2019in yakla\u015f\u0131k 1500 kat\u0131 \u00e7apa sahip oldu\u011funu s\u00f6yledi\u011fi, B\u00fcy\u00fck Macellan Bulutu\u2019nda bulunan ve k\u0131rm\u0131z\u0131 s\u00fcper-devler olan (2018 tarihli bir makaleye g\u00f6re 5 milyon ya\u015f\u0131ndan daha gen\u00e7 olan) \u2018WOH G64\u2019 ve (2011 tarihli bir makaleye g\u00f6re yakla\u015f\u0131k 8.2 milyon ya\u015f\u0131nda olan) \u2018VY Canis Majoris\u2019 bulunuyor (Ve mevcut belirsizlik hesaba kat\u0131ld\u0131\u011f\u0131nda, boyut a\u00e7\u0131s\u0131ndan her iki y\u0131ld\u0131z da UY Scuti\u2019yi geride b\u0131rakabilir). Massey, \u201cHer iki durumda da inan\u0131lmaz derecede haval\u0131 oldu\u011funu d\u00fc\u015f\u00fcn\u00fcyorum\u201d diyor. Bu y\u0131ld\u0131zlardan herhangi biri g\u00fcne\u015f sistemimizin merkezindeki G\u00fcne\u015f\u2019in yerini alsayd\u0131, J\u00fcpiter\u2019e var\u0131ncaya kadar ve J\u00fcpiter de dahil olmak \u00fczere, t\u00fcm i\u00e7 gezegenleri i\u00e7lerine al\u0131rlard\u0131. Massey, \u201cD\u00fcnya dahil, t\u00fcm i\u00e7 gezegenler buharla\u015f\u0131rd\u0131\u201d diye ekliyor.<\/p>\n