NGC 6984

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NGC 6984
Stellar explosions in NGC 6984.jpg
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]
Heliocentric radial velocity 4577 km/s [1]
Distance 180 million ly [2]
Apparent magnitude  (V)12.65 [1]
Apparent magnitude  (B)13.19 [1]
Surface brightness 22.82 mag/arcsec² [3]
magnitude  (J)10.94 [3]
magnitude  (H)10.25 [3]
magnitude  (K)9.99 [3]
Characteristics
Type Spiral (SAc) [3]
Apparent size  (V)1.403 x 1.038 arcmin [1]
Other designations
IRAS 20543-5203, 2MASX J20575398-5152151, 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]

Contents

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]

Related Research Articles

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NGC 3184, the Little Pinwheel Galaxy, is a spiral galaxy approximately 40 million light-years away in the constellation Ursa Major. Its name comes from its resemblance to the Pinwheel Galaxy. It was discovered on 18 March 1787 by German-British astronomer William Herschel. It has two HII regions named NGC 3180 and NGC 3181.

<span class="mw-page-title-main">NGC 772</span> Galaxy in the constellation Aries

NGC 772 is an unbarred spiral galaxy approximately 106 million light-years away in the constellation Aries. It was discovered on 29 November 1785 by German-British astronomer William Herschel.

<span class="mw-page-title-main">NGC 2207 and IC 2163</span> Pair of colliding spiral galaxies in the constellation Canis Major

NGC 2207 and IC 2163 are a pair of colliding spiral galaxies about 80 million light-years away in the constellation Canis Major. Both galaxies were discovered by John Herschel in 1835.

<span class="mw-page-title-main">Arp 271</span> Interacting galaxies in the constellation Virgo

Arp 271 is a pair of similarly sized interacting spiral galaxies, NGC 5426 and NGC 5427, in the constellation of Virgo. It is not certain whether the galaxies are going to eventually collide or not. They will continue interacting for tens of millions of years, creating new stars as a result of the mutual gravitational attraction between the galaxies, a pull seen in the bridge of stars already connecting the two. Located about 130 million light-years away, the Arp 271 pair is about 130,000 light-years across. It was originally discovered in 1785 by William Herschel. It is speculated, that the Milky Way will undergo a similar collision in about five billion years with the neighbouring Andromeda Galaxy, which is currently located about 2.6 million light-years away.

<span class="mw-page-title-main">NGC 3198</span> Galaxy in the constellation Ursa Major

NGC 3198, also known as Herschel 146 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on 15 January 1788. NGC 3198 is located in the Leo Spur, which is part of the Virgo Supercluster, and is approximately 47 million light years away.

<span class="mw-page-title-main">NGC 3021</span> Galaxy in the constellation Leo Minor

NGC 3021 is a spiral galaxy in the northern constellation of Leo Minor. It is about 93 million light-years away from Earth, and is receding with a heliocentric radial velocity of 1,537±4 km/s. This galaxy was discovered December 7, 1785 by Anglo-German astronomer William Herschel. The morphological classification of NGC 3021 is SA(rs)bc, which indicates a spiral galaxy with no central bar (SA), an incomplete inner ring structure (rs), and moderate to loosely wound spiral arms (bc).

<span class="mw-page-title-main">NGC 488</span> Spiral galaxy in the constellation Pisces

NGC 488 is a face-on spiral galaxy in the constellation Pisces. It is at a distance of about 90 million light-years away from Earth. Its diameter is estimated to be 52,6 Kpc. The galaxy has a large central bulge, and is considered a prototype galaxy with multiple spiral arms. Its arms are tightly wound. Star forming activity has been traced within the arms. The nucleus of NGC 488 has been found to be chemically decoupled, being twice as metal rich as the central bulge of the galaxy. NGC 488, with the exception of its smaller companions, that form NGC 488 group, is an isolated galaxy.

<span class="mw-page-title-main">NGC 1084</span> Galaxy in the constellation Eridanus

NGC 1084 is an unbarred spiral galaxy in the constellation Eridanus. It is located at a distance of about 63 million light-years away from the Milky Way. The galaxy was discovered by William Herschel on 10 January 1785. It has multiple spiral arms, which are not well defined. It belongs in the same galaxy group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. This group is in turn associated with the Messier 77 group.

<span class="mw-page-title-main">NGC 908</span> Spiral galaxy in the constellation Cetus

NGC 908 is an unbarred spiral galaxy in the constellation Cetus. It was discovered on 20 September 1786 by William Herschel. This galaxy is 56 million light years away from Earth. It is the main galaxy in the NGC 908 group, which also includes NGC 899, NGC 907, and IC 223.

<span class="mw-page-title-main">NGC 1448</span> Galaxy in the constellation Horologium

NGC 1448 or NGC 1457 is an unbarred spiral galaxy seen nearly edge-on in the constellation Horologium. It is at a distance of 55 million light years from Earth. It was discovered by John Herschel in 1835.

<span class="mw-page-title-main">NGC 1961</span> Galaxy in the constellation Camelopardis

NGC 1961 is a spiral galaxy in the constellation Camelopardalis. It was discovered by William Herschel on 3 December 1788. It is at a distance of about 200 million light years from Earth, which, given its apparent dimensions, means that NGC 1961 is more than 220,000 light years across.

<span class="mw-page-title-main">NGC 5468</span> Spiral galaxy in the constellation Virgo

NGC 5468 is an intermediate spiral galaxy located in the constellation Virgo. It is located at a distance of about 140 million light-years from Earth, which, given its apparent dimensions, means that NGC 5468 is about 110,000 light-years across. It was discovered by William Herschel on March 5, 1785.

<span class="mw-page-title-main">NGC 2525</span> Galaxy in the constellation Puppis

NGC 2525 is a barred spiral galaxy located in the constellation Puppis. It is located at a distance of about 70 million light years from Earth, which, given its apparent dimensions, means that NGC 2525 is about 60,000 light years across. It was discovered by William Herschel on February 23, 1791.

<span class="mw-page-title-main">NGC 6365</span> Galaxy pair in the constellation Draco

NGC 6365 is a pair of spiral galaxies in the constellation Draco. It consists of two galaxies, PGC 60174 to the south, and PGC 60171 to the north. These two galaxies are also designated respectively by the NASA/IPAC database as NGC 6365A and NGC 6365B. This pair of galaxies was discovered by German astronomer Lewis Swift in 1884.

<span class="mw-page-title-main">NGC 4375</span> Galaxy in the constellation Coma Berenices

NGC 4375 is a barred spiral galaxy in the constellation of Coma Berenices. Its velocity with respect to the cosmic microwave background is 9325 ± 20 km/s, which corresponds to a Hubble distance of 137.54 ± 9.63 Mpc. However, four non-redshift measurements give a distance of 105.5 Mpc. The galaxy was discovered by German-British astronomer William Herschel on 11 April 1785.

<span class="mw-page-title-main">NGC 3362</span> Galaxy in the constellation Leo

NGC 3362 is a intermediate spiral galaxy in the constellation of Leo. Its velocity with respect to the cosmic microwave background is 8676 ± 25 km/s, which corresponds to a Hubble distance of 127.97 ± 8.97 Mpc. However, three non redshift measurements give a distance of 95.8 ± 3.984 Mpc. The galaxy was discovered by German astronomer Albert Marth on 22 March 1865.

<span class="mw-page-title-main">NGC 664</span> Galaxy in the constellation Pisces

NGC 664 is a spiral galaxy in the constellation of Pisces. Its velocity with respect to the cosmic microwave background is 5137 ± 21 km/s, which corresponds to a Hubble distance of 247.1 ± 17.3 Mly (75.77 ± 5.31 Mpc). In addition, six non redshift measurements give a distance of 218.91 ± 3.66 Mly (67.117 ± 1.123 Mpc). It was discovered by British astronomer John Herschel on 24 September 1830.

<span class="mw-page-title-main">NGC 735</span> Galaxy in the constellation Triangulum

NGC 735 is a spiral galaxy in the constellation of Triangulum. Its velocity with respect to the cosmic microwave background is 4374 ± 18 km/s, which corresponds to a Hubble distance of 210.4 ± 14.7 Mly (64.52 ± 4.52 Mpc). In addition, eight non redshift measurements give a distance of 227.21 ± 7.99 Mly (69.662 ± 2.449 Mpc). The galaxy was discovered by German-British astronomer William Herschel on 13 September 1784).

<span class="mw-page-title-main">NGC 2466</span> Galaxy in the constellation Volans

NGC 2466 is a spiral galaxy in the constellation of Volans. Its velocity with respect to the cosmic microwave background is 5428 ± 10 km/s, which corresponds to a Hubble distance of 261.2 ± 18.3 Mly (80.07 ± 5.61 Mpc). The galaxy was discovered by British astronomer John Herschel on 20 February 1835.

<span class="mw-page-title-main">NGC 5605</span> Galaxy in the constellation Libra

NGC 5605 is an intermediate spiral galaxy in the constellation of Libra. Its velocity with respect to the cosmic microwave background is 3635 ± 18 km/s, which corresponds to a Hubble distance of 174.9 ± 12.3 Mly (53.61 ± 3.76 Mpc). In addition, three non redshift measurements give a distance of 194.72 ± 0.68 Mly (59.700 ± 0.208 Mpc). The galaxy was discovered by German-British astronomer William Herschel on 11 May 1784.

References

  1. 1 2 3 4 5 6 7 "Search Results for NGC 6984". Astronomical Database. SIMBAD . Retrieved 5 November 2013.
  2. ↑ "Stellar explosions in NGC 6984". ESA/Hubble Picture of the Week. Retrieved 5 November 2013.
  3. 1 2 3 4 5 6 "NGC 6984 - Spiral Galaxy in Indus". thesky.com. The Sky LIVE. Retrieved 12 Sep 2024.
  4. ↑ "NGC 6984". simbad.u-strasbg.fr. Retrieved 12 Sep 2024.
  5. ↑ Seligman, Courtney. "NGC 6984". Celestial Atlas. Retrieved 22 August 2024.
  6. ↑ "SN 2012im/2013ek: A Supernova Double Take in NGC 6984". SAO Astrophysics Data System (ADS). AAS Meeting #223, id.354.29. January 2014. Retrieved 12 Sep 2024.
  7. ↑ "SN 2012im". Transient Name Server. IAU . Retrieved 22 August 2024.
  8. ↑ "ATel #4300: PESSTO spectroscopic classification of optical transients".
  9. ↑ "CBET 3607 : 20130728 : SUPERNOVAE 2012im AND 2013ek IN NGC 6984" . Central Bureau for Astronomical Telegrams (CBET). Retrieved 12 Sep 2024.
  10. ↑ "ATel #5225: A new SN suspect at the position of SNhunt142 discovered 1 year ago".
  11. ↑ "SN 2013ek". Transient Name Server. IAU . Retrieved 22 August 2024.
  12. ↑ "ATel #5227: Spectroscopic classification for PSN J20575390-5152245 with FLOYDS at Faulkes Telescope South".
  13. ↑ "13505 Program Information".
  14. ↑ Hubble Catches Stellar Explosions in NGC 6984, NASA, 13 November 2013, archived from the original on 21 November 2013


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