Astronomy:NGC 6984
| NGC 6984 | |
|---|---|
 NGC 6984 imaged by the Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Indus |
| Right ascension | 20h 57m 53.987s[1] |
| Declination | −51° 52′ 15.13″[1] |
| Redshift | 0.015386[1] |
| Helio radial velocity | 4577 km/s[1] |
| Distance | 180 million ly[2] |
| Apparent magnitude (V) | 12.65[1] |
| Apparent magnitude (B) | 13.19[1] |
| Characteristics | |
| Type | Spiral (SAc)[3] |
| Apparent size (V) | 1.403 x 1.038 arcmin[1] |
| Other designations | |
| IRAS 20543-5203, PGC 65798, AM 2054-520, APMBGC 235+046+104, ISOSS J20578-5152, SGC 205419-5203.8, ESO 235- G 020 | |
NGC 6984 is a barred spiral galaxy located 180 million light years away in the constellation Indus. It is a Type II Seyfert galaxy, a type of active galactic nucleus (AGN).[4] It is situated south of the celestial equator, and is visible with the help of a telescope having an aperture of 10 inches (250 mm) or more.[3] It was discovered on 8 July 1834 by British astronomer John Herschel.[5]
Supernovae
NGC 6984 is notable for having been the host of two supernovae which occurred in the same location (< 0.4 arcsec),[6] about 1 year apart: SN 2012im (type Ic, mag. 18.9),[7] first known as SNhunt142,[8][9][10] and SN 2013ek (type Ib/c, mag. 16.9).[11][12] Hubble Space Telescope observations were initiated by Dr. Dan Milisavljevic.[13] NASA's press release about SN 2013ek said:
"It is so close to where SN 2012im was spotted that the two events are thought to be linked; the chance of two completely independent supernovae so close together and of the same class exploding within one year of one another is a very unlikely event. It was initially suggested that SN 2013ek may in fact be SN 2012im flaring up again, but further observations support the idea that they are separate supernovae — although they may be closely related in some as-yet-unknown way."[14]
Gallery
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The galaxy NGC 6984, an elegant spiral galaxy in the constellation Indus roughly 200 million light-years away from Earth.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "Search Results for NGC 6984". Astronomical Database. SIMBAD. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+6984.
- ↑ "Stellar explosions in NGC 6984". ESA/Hubble Picture of the Week. http://www.spacetelescope.org/images/potw1344a/.
- ↑ 3.0 3.1 "NGC 6984 - Spiral Galaxy in Indus". The Sky LIVE. https://theskylive.com/sky/deepsky/ngc6984-object.
- ↑ "NGC 6984". https://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+6984.
- ↑ Seligman, Courtney. "NGC 6984". https://cseligman.com/text/atlas/ngc69a.htm#6984.
- ↑ "SN 2012im/2013ek: A Supernova Double Take in NGC 6984". SAO Astrophysics Data System (ADS). AAS Meeting #223, id.354.29. January 2014. https://ui.adsabs.harvard.edu/abs/2014AAS...22335429M/abstract.
- ↑ "SN 2012im". IAU. https://www.wis-tns.org/object/2012im.
- ↑ "ATel #4300: PESSTO spectroscopic classification of optical transients". http://www.astronomerstelegram.org/?read=4300.
- ↑ "CBET 3607 : 20130728 : SUPERNOVAE 2012im AND 2013ek IN NGC 6984". Central Bureau for Astronomical Telegrams (CBET). http://www.cbat.eps.harvard.edu/cbet/003600/CBET003607.txt.
- ↑ "ATel #5225: A new SN suspect at the position of SNhunt142 discovered 1 year ago". http://www.astronomerstelegram.org/?read=5225.
- ↑ "SN 2013ek". IAU. https://www.wis-tns.org/object/2013ek.
- ↑ "ATel #5227: Spectroscopic classification for PSN J20575390-5152245 with FLOYDS at Faulkes Telescope South". http://www.astronomerstelegram.org/?read=5227.
- ↑ "13505 Program Information". http://www.stsci.edu/cgi-bin/get-proposal-info?id=13505&observatory=HST.
- ↑ Hubble Catches Stellar Explosions in NGC 6984, NASA, 13 November 2013, http://www.nasa.gov/content/goddard/stellar-explosions-in-ngc-6984/#.UoOpbJTXiBM
External links
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