G1.9+0.3
{{Short description|Supernova remnant in the constellation of Sagittarius}}
{{Infobox supernova
|ra = {{RA|17|48|45.4}}
|dec = {{DEC|-27|10|06}}
|discovery = {{circa}} 27,600 years ago
(discovered 1984)
|predecessor = SN 1604 (observed), Cassiopeia A (unobserved, {{circa|1680}})
|successor = SN 1885A
|event_type=Supernova remnant|distance={{circa}} 27,700 ly|host=Milky Way|constellation=Sagittarius|detected_by=VLA radio telescope|progenitor=2 White dwarfs}}
G1.9+0.3 is a supernova remnant (SNR) in the constellation of Sagittarius. It is the youngest-known SNR in the Milky Way, resulting from an explosion the light from which would have reached Earth some time between 1890 and 1908.{{cite web| title = G1.9+0.3: Discovery of Most Recent Supernova in Our Galaxy. |work=Chandra X-ray Observatory | publisher = NASA | date = 2008-05-14 | url = http://chandra.harvard.edu/photo/2008/g19/ | access-date = 2008-05-14 }} The explosion was not seen from Earth as it was obscured by the dense gas and dust of the Galactic Center, where it occurred. The remnant's young age was established by combining data from NASA's Chandra X-ray Observatory and the VLA radio observatory. It was a type Ia supernova.{{cite web |title=G1.9+0.3: The Remarkable Remains of a Recent Supernova |url=http://chandra.harvard.edu/photo/2013/g19/ |work=Chandra X-ray Observatory |publisher=NASA |date=2013-06-26 |access-date=2021-10-11}}{{cite press release | url=https://www.nasa.gov/mission_pages/chandra/trigger-for-milky-way-s-youngest-supernova-identified.html | author= | title=Trigger for Milky Way's Youngest Supernova Identified | publisher=NASA | date=March 30, 2016 | access-date=2017-01-22}}{{cite journal |last1=Chakraborti |first1=Sayan |last2=Childs |first2=Francesca |last3=Soderberg |first3=Alicia |author3-link=Alicia Soderberg |date=February 25, 2016 |title=Young Remnants of Type Ia Supernovae and Their Progenitors: A Study Of SNR G1.9+0.3 |journal=The Astrophysical Journal |volume=819 |issue=1 |pages= 37|doi=10.3847/0004-637X/819/1/37 |arxiv = 1510.08851 |bibcode = 2016ApJ...819...37C |s2cid=119246128 |doi-access=free }} The remnant has a radius of over 1.3 light-years.
Discovery
G1.9+0.3 was first identified as an SNR in 1984 from observations made with the VLA radio telescope.{{cite journal | author = Green, D.A. |author2=S.F. Gull | title = Two new young galactic supernova remnants |journal = Nature |date=December 1984 | volume = 312 | issue = 5994 | pages = 527–529 | doi = 10.1038/312527a0 | bibcode = 1984Natur.312..527G |s2cid=4355199 }} Because of its unusually small angular size, it was thought to be young—less than about one thousand years old. In 2007, X-ray observations made with the Chandra X-ray Observatory revealed that the object was about 15% larger than in the earlier VLA observations.{{cite journal | author = Reynolds, S. P. | author2 = K. J. Borkowski | author3 = D. A. Green | author4 = U. Hwang | author5 = I. Harrus | author6 = R. Petre | title = The Youngest Galactic Supernova Remnant: G1.9+0.3 | publisher = American Astronomical Society |date=June 2008 | volume = 680 | issue = 1 | pages = L41–L44 | doi = 10.1086/589570 | bibcode = 2008ApJ...680L..41R | arxiv = 0803.1487 | journal = Astrophysical Journal Letters | s2cid = 67766657 }} Further observations made with the VLA in 2008 verified increase in size, implying it is no more than 150 years old.{{cite journal | author = Green, D. A. | author2 = S. P. Reynolds | author3 = K. J. Borkowski | author4 = U. Hwang | author5 = I. Harrus | author6 = R. Petre | title = The radio expansion and brightening of the very young supernova remnant G1.9+0.3 | publisher = Monthly Notices of the Royal Astronomical Society |date=June 2008 | volume = 387 | issue = 1 | pages = L54–L58 | doi = 10.1111/j.1745-3933.2008.00484.x | bibcode = 2008MNRAS.387L..54G | arxiv = 0804.2317 | journal = Monthly Notices of the Royal Astronomical Society Letters | doi-access = free | s2cid = 18759493 }} A more recent estimate put its observable age at 110 years as of the data collection in 2008. That study also found that it was probably triggered by the merger of two white dwarf stars.
Announcement
The discovery that G1.9+0.3 had been identified as the youngest-known Galactic SNR was announced on May 14, 2008 at a NASA press conference. In the days leading up to the announcement, NASA said that they were going "to announce the discovery of an object in our Galaxy astronomers have been hunting for more than 50 years."{{cite press release | title = NASA to Announce Success of Long Galactic Hunt | publisher = NASA | url = http://www.nasa.gov/home/hqnews/2008/may/HQ_M08089_Chandra_Advisory.html | date = 2008-05-07 | access-date = 2008-05-14 | archive-date = 2021-03-30 | archive-url = https://web.archive.org/web/20210330155654/https://www.nasa.gov/home/hqnews/2008/may/HQ_M08089_Chandra_Advisory.html | url-status = dead }} Before this discovery, the youngest-known Milky Way supernova remnant was Cassiopeia A, at about 330 years.
References
{{reflist|2}}
External links
- {{cite web|url=http://www.mrao.cam.ac.uk/~dag/my-G1.9+0.3.html|title=Dave Green's research: G1.9+0.3|author=Green, Dave|publisher=University of Cambridge}}
- {{cite simbad|title=SNR G001.9+00.3}}
{{Sky|17|48|45.4|-|27|10|06|25000}}
{{supernovae}}