SDSS J1229+1122 (SDSS J122952.66+112227.8) is a
blue supergiant
A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They are usually considered to be those with luminosity class I and spectral class B9 or earlier, although sometimes A-class supergiants are also deemed blu ...
O-type star in the tail of
dwarf irregular galaxy
IC 3418. It illuminates a
nebula
A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...
clump of gas, and was discovered from the spectrum of the illumination source. The clump of gas resides in a tail caused by
ram pressure
Ram pressure is a pressure exerted on a body moving through a fluid medium, caused by relative bulk motion of the fluid rather than random thermal motion. It causes a drag (physics), drag force to be exerted on the body. Ram pressure is given in ...
stripping of gas from the galaxy by the galaxy cluster.
It was determined to be a blue supergiant through analysis of its spectrum taken with the 8m
Subaru telescope.
The discovery was made by Youichi Ohyama and Ananda Hota,
using the
Subaru Telescope.
This discovery was then followed up with the
AstroSat to image it with finer angular resolution in the ultraviolet than that of
GALEX. With addition of
HST optical data the astronomers believe that the ram pressure stripped tail of IC3418 many have many such young star forming clumps and potentially single O-type stars.
Until the discovery of the doubly
gravitationally lensed MACS J1149 Lensed Star 1 (also known as Icarus) in 2018, SDSS J1229+1122 was the most distant-known star, at (stars more distant than this are only known through events that they cause, such as stellar explosions of
supernova
A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...
e and
gamma ray burst
In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme electromagnetic emissions are second ...
s).
(The record for the most distant star is
Earendel, as of October 2023.)
The star (SDSS J1229+1122) and its galaxy are in the
Virgo Cluster
The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the Virgo constellation. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the larger ...
of galaxies. The clump of gas that the star illuminates is referred to as ''D3'' or ''IC3418 D3'', and lies within a filamentary structure referred to as ''F1'' or ''IC3418 F1''.
[ The galactic tail and all within it are escaping the galaxy to become intracluster flotsam, unattached to any galaxy, just the cluster.][
]
References
{{DEFAULTSORT:SDSS J1229+1122
Stars in IC 3418
O-type supergiants
Extragalactic stars
IC 3418
Virgo Cluster
Virgo (constellation)
SDSS objects