CK Vulpeculae

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CK Vulpeculae
Through the Hourglass CK Vulpeculae.tif
CK Vulpeculae taken by ALMA. [1]
Credit: ALMA (ESO/NAOJ/NRAO)/S. P. S. Eyres
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Vulpecula
Right ascension 19h 47m 38.0s [2]
Declination +27° 18′ 48″ [2]
Apparent magnitude  (V)max 2.6 [2]
Characteristics
B−V color index 0.7 [3]
Variable type unknown [3]
Astrometry
Distance 10000+3000
−2000 [4]   ly
(3200+900
−600 [4]   pc)
Details
Luminosity 0.9 [3]   L☉
Temperature 14,000 – 100,000 [3]   K
Other designations
CK  Vulpeculae, CK  Vul, Nova  Vul 1670, HR  7539, 11 Vul [5]
Database references
SIMBAD data

CK Vulpeculae (also Nova Vulpeculae 1670) is an object whose exact nature is unknown. [4] It was once considered to be the oldest reliably-documented nova. It consists of a compact central object surrounded by a bipolar nebula.

Contents

Models suggest CK Vulpeculae may not be a classic nova; rather it may be classified as a luminous red nova which is the result of two main sequence stars colliding and merging. A 2018 study found it was most likely the result of an unusual collision of a white dwarf and a brown dwarf. A 2020 article ruled out this proposed mechanism and proposes that CK Vulpeculae is an intermediate luminosity optical transient, i.e. an object in the luminosity gap between supernovae and novae. [4]

Eruptive history

Position of the 1670 Nova near Albireo Nova of 1670 by Hevelius.jpg
Position of the 1670 Nova near Albireo
The location of CK Vulpeculae (circled in red) CKVulLocation.png
The location of CK Vulpeculae (circled in red)

CK Vulpeculae was discovered on June 20, 1670, by Voituret Anthelme and independently on July 25 by Johannes Hevelius. It had a brightness maximum of approximately magnitude 3 at its discovery after which it faded. A second maximum of approximately 2.6 magnitude was observed in March 1671, after which Johannes Hevelius and Giovanni Cassini observed it throughout spring and summer until it faded from naked-eye view in late August 1671. A last weakly visible brightness maximum of approximately 5.5 to 6 magnitude was observed by Hevelius in March 1672 and finally faded from view late May. [6]

This was the first nova for which there are multiple and reliable observations. The next nova to be documented as comprehensively was Nova Ophiuchi 1841. [6]

Identification

Visible light is in blue, submillimeter radiation map highlighted in green, and molecular emission in red. CK Vulpeculae.jpg
Visible light is in blue, submillimeter radiation map highlighted in green, and molecular emission in red.

John Flamsteed, who was elaborating his catalogue during these years, assigned the star the Flamsteed designation 11 Vulpeculae, [5] which has been noted later by Francis Baily as one of Flamsteed's lost stars, because it had not been detectable for centuries. [7]

In 1981, a point source near the centre of a small nebula was identified as CK Vulpeculae, with an estimated red magnitude of 20.7. [8] [6] Later observations cast doubt on that identification, [9] and it is now known to be a background object. That object and another star are thought to be seen though dense nebulosity associated with CK Vulpeculae which causes them to vary dramatically in brightness. [10]

CK Vulpeculae now consists of a compact central object with gas flowing out at approximately 210  km/s into a bipolar nebula. [10] A 15" path of nebulosity seen in the 1980s lies at the centre of a 70" bipolar nebula. [11] A compact radio source is seen at the centre of this nebula, and an infrared point source, but it has not been detected at optical wavelengths. [3] The ionisation of the nebula and its radio emission indicate that the central source is still very hot and relatively luminous. [12] [10] It is either inside of a cloud of cold (~ 15 K) dust or the cloud is in front of it from the Earth's perspective. Molecular gas in the vicinity is rich in nitrogen relative to oxygen. [12]

Properties

Radioactive molecules in the remains of a stellar collision. Radioactive molecules in the remains of a stellar collision CK Vulpeculae.tif
Radioactive molecules in the remains of a stellar collision.

The luminosity of the central object, estimated from infrared dust emission, is about 0.9 L☉. [3] The luminosity required to energise the observed nebulosity is calculated at 3 L☉ from an object at 60,000 K [10] At the time of its eruption, the luminosity of CK Vulpeculae is calculated to have been at least 7,000,000 L☉. [4] Known ionic emission lines in the spectrum, and unidentified absorption features in the infrared indicate a temperature between 14,000 K and 100,000 K. [3]

Astronomers using the Atacama Large Millimetre Array (ALMA) and the Northern Extended Millimeter Array (NOEMA) radio telescopes to study CK Vulpeculae have found the first convincing evidence of a radioactive molecule outside the Earth's Solar System, which is aluminium monofluoride as the 26Al isotopologue. [14]

Nature of the eruption

In the past, a luminous red nova merger, very late thermal pulse, or a diffusion-induced nova have all been suggested but there are problems with all these explanations. [3] An analysis of the structures and isotopic abundances in the remaining nebula using the Atacama Large Millimeter Array (ALMA) in 2018 concluded that the nova and associated nebula were caused by the unusual merger of a white dwarf and brown dwarf between 1670 and 1672. [15] Although it was previously considered to be located about 2,280 ly (700 pc) away, [10] a 2020 paper ruled this out due to a larger distance for CK Vulpeculae making the intrinsic energy release too great for a stellar merger. Instead the 2020 paper concludes that the CK Vulpeculae outburst was an intermediate luminosity optical transient with an unknown cause. [4]

Related Research Articles

<span class="mw-page-title-main">Nova remnant</span> Cosmic matter (remnant)

A nova remnant is made up of the material either left behind by a sudden explosive fusion eruption by classical novae, or from multiple ejections by recurrent novae. Over their short lifetimes, nova shells show expansion velocities of around 1000 km/s, whose faint nebulosities are usually illuminated by their progenitor stars via light echos as observed with the spherical shell of Nova Persei 1901 or the energies remaining in the expanding bubbles like T Pyxidis.

<span class="mw-page-title-main">Alpha Vulpeculae</span> Star in the constellation Vulpecula

Alpha Vulpeculae, officially named Anser, is the brightest star in the constellation of Vulpecula. It is approximately 291 light-years from Earth. It forms a wide optical binary with 8 Vulpeculae.

<span class="mw-page-title-main">V476 Cygni</span> Star in the constellation Cygnus

V476 Cygni or Nova Cygni 1920 was a nova which occurred in the constellation Cygnus in 1920. It was discovered by William Frederick Denning, an English amateur astronomer, at 09:30 GMT on 20 August 1920, at which time it had a magnitude of 3.7. It reached a peak brightness of magnitude 1.7 on 23 August 1920. Its quiescent brightness is magnitude 17.09.

<span class="mw-page-title-main">NQ Vulpeculae</span> 1976 Nova seen in the constellation Vulpecula

NQ Vulpeculae also known as Nova Vulpeculae 1976, was a nova that appeared in the constellation Vulpecula in 1976. It was discovered visually at 18:20 UT on October 21, 1976 by English amateur astronomer George Alcock. Its apparent magnitude at the time of discovery was 6.5 It reached its maximum brightness of magnitude 6.0 thirteen days after its discovery, at which point it may have been faintly visible to the naked eye. A few days after maximum brightness, it had faded to magnitude 8.3.

<span class="mw-page-title-main">V1494 Aquilae</span> Nova seen in 1999 in the constellation of Aquila

V1494 Aquilae or Nova Aquilae 1999 b was a nova which occurred during 1999 in the constellation Aquila and reached a brightness of magnitude 3.9 on 2 December 1999. making it easily visible to the naked eye. The nova was discovered with 14×100 binoculars by Alfredo Pereira of Cabo da Roca, Portugal at 18:50 UT on 1 December 1999, when it had a visual magnitude of 6.0.

<span class="mw-page-title-main">QU Vulpeculae</span> 1984 Nova seen in the constellation Vulpecula

QU Vulpeculae, also known as Nova Vulpeculae 1984 Number 2, was the second nova which occurred in 1984 in the constellation Vulpecula. It was discovered by Peter Collins, an amateur astronomer from Cardiff, California at 22:08 UT on 22 December 1984. At the time of its discovery, the nova's apparent magnitude was 6.8. By the next night, Collins reported its brightness had increased to magnitude 5.6, making it visible to the naked eye.

<span class="mw-page-title-main">HD 189733</span> Binary star system in the constellation Vulpecula

HD 189733, also catalogued as V452 Vulpeculae, is a binary star system approximately 64.5 light-years away in the constellation of Vulpecula. The primary star is suspected to be an orange dwarf star, while the secondary star is a red dwarf star. Given that this system has the same visual magnitude as HD 209458, it promises much for the study of close transiting extrasolar planets. The star can be found with binoculars 0.3 degrees east of the Dumbbell Nebula (M27).

<span class="mw-page-title-main">Sakurai's Object</span> Star in the constellation Sagittarius

Sakurai's Object is a star in the constellation of Sagittarius. It is thought to have previously been a white dwarf that, as a result of a very late thermal pulse, swelled and became a red giant. It is located at the center of a planetary nebula and is believed to currently be in thermal instability and within its final shell helium flash phase.

<span class="mw-page-title-main">13 Vulpeculae</span> Star in the constellation Vulpecula

13 Vulpeculae is a blue giant with a stellar classification of class B9.5III in the northern constellation Vulpecula. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.57 and it is approximately 339 light years away from the Sun based on parallax. The star is radiating 180 times the luminosity of the Sun from its photosphere at an effective temperature of 8,801 K.

<span class="mw-page-title-main">15 Vulpeculae</span> Star in the constellation Vulpecula

15 Vulpeculae is a variable star in the northern constellation of Vulpecula, located approximately 243 light years away based on parallax. It has the variable star designation NT Vulpeculae; 15 Vulpeculae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a typical apparent visual magnitude of 4.66. This object is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.

<span class="mw-page-title-main">12 Vulpeculae</span> Star in the constellation Vulpecula

12 Vulpeculae is a star in the northern constellation of Vulpecula, located approximately 630 light years away based on parallax. It has the variable star designation V395 Vul; 12 Vulpeculae is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 4.928. It is moving closer to the Earth with a heliocentric radial velocity of -25 km/s.

<span class="mw-page-title-main">3 Vulpeculae</span> Star in the constellation Vulpecula

3 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located around 360 light years away from the Sun. 3 Vulpeculae is its Flamsteed designation. It is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.18.

<span class="mw-page-title-main">V605 Aquilae</span> Star in the constellation Aquila

V605 Aquilae, in the constellation Aquila, is the variable central star of the planetary nebula Abell 58. It is a highly unusual hydrogen-deficient carbon-rich star.

V1309 Scorpii is a contact binary that merged into a single star in 2008 in a process known as a luminous red nova. It was the first star to provide conclusive evidence that contact binary systems end their evolution in a stellar merger. Its similarities to V838 Monocerotis and V4332 Sagittarii allowed scientists to identify these stars as merged contact binaries as well.

An Intermediate Luminosity Optical Transient (ILOT) is an astronomical object which undergoes an optically detectable explosive event with an absolute magnitude (M) brighter than a classical nova (M ~ -8) but fainter than that of a supernova (M ~ -17). That nine magnitude range corresponds to a factor of nearly 4000 in luminosity, so the ILOT class may include a wide variety of objects. The term ILOT first appeared in a 2009 paper discussing the nova-like event NGC 300 OT2008-1. As the term has gained more widespread use, it has begun to be applied to some objects like KjPn 8 and CK Vulpeculae for which no transient event has been observed, but which may have been dramatically affected by an ILOT event in the past. The number of ILOTs known is expected to increase substantially when the Vera C. Rubin Observatory becomes operational.

<span class="mw-page-title-main">LV Vulpeculae</span> Nova seen in 1968 in the constellation Vulpecula

LV Vulpeculae, also known as Nova Vulpeculae 1968 no. 1, was the first of two novae in the constellation of Vulpecula which erupted in 1968. It was discovered by George Alcock who observed it from the back garden of his home in Farcet, England, on the morning of 15 April 1968. The next night it was independently discovered by Midtskoven in Norway. It reached a peak apparent magnitude of 4.79 on 17 April 1968. It was visible to the naked eye at the same time HR Delphini was a naked eye object, and the two novae were less than 15 degrees apart on the sky.

<span class="mw-page-title-main">WY Sagittae</span> 1783 Nova seen in the constellation Sagitta

WY Sagittae, also known as Nova Sagittae 1783, is a star in the constellation Sagitta which had a nova eruption visible in 1783. It was discovered on 26 July 1783 by the French astronomer Joseph Lepaute D'Agelet. It is usually difficult to precisely identify novae that were discovered hundreds of years ago, because the positions were often vaguely reported and historically there was not a clear distinction drawn between different sorts of transient astronomical events such as novae and comet apparitions. However D'Agelet observed this nova with a mural quadrant, which produced coordinates accurate enough to allow modern astronomers to identify the star. D'Agelet reported the apparent magnitude of the star as 6, but Benjamin Apthorp Gould, who analysed D'Agelet's records, determined that what D'Agelet called magnitude 6 corresponds to magnitude 5.4 ± 0.4 on the modern magnitude scale, so the nova was visible to the naked eye.

<span class="mw-page-title-main">V1370 Aquilae</span> Nova that occurred in 1982

V1370 Aquilae, also known as Nova Aquilae 1982, is a nova that appeared in the constellation Aquila during 1982. It was discovered by Minoru Honda of Kurashiki, Japan at 20:30 UT on 27 January 1982. At that time the Sun had moved just far enough from Aquila to allow the nova to be seen in the morning sky. Although it was discovered photographically, its apparent magnitude was 6–7, making it potentially visible to the naked eye under ideal conditions. A possible magnitude 20 progenitor was located on the Palomar Sky Survey prints. Spectra of the object were taken in February 1982 at Asiago Astrophysical Observatory, which confirmed that it is a nova.

<span class="mw-page-title-main">PU Vulpeculae</span> Variable star in the constellation Vulpecula

PU Vulpeculae is a very slowly evolving symbiotic nova in the northern constellation of Vulpecula, abbreviated PU Vul. It is too faint to be visible to the naked eye, reaching a maximum apparent visual magnitude of 8.7 following a minimum of 16.6. The system is located at a distance of approximately 17,000 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">QQ Vulpeculae</span> Variable star in the constellation Vulpecula

QQ Vulpeculae is a cataclysmic variable binary star system in the northern constellation of Vulpecula, abbreviated QQ Vul. It has a brightness that fluctuates around an apparent visual magnitude of 14.7, which is too faint to be viewed with the naked eye. The distance to this system is approximately 981 light years based on parallax measurements.

References

  1. ↑ "Through the Hourglass". www.eso.org. Retrieved 8 October 2018.
  2. 1 2 3 Downes, Ronald A; Webbink, Ronald F; Shara, Michael M; Ritter, Hans; Kolb, Ulrich; Duerbeck, Hilmar W (2001). "A Catalog and Atlas of Cataclysmic Variables: The Living Edition". The Publications of the Astronomical Society of the Pacific. 113 (784): 764. arXiv: astro-ph/0102302 . Bibcode:2001PASP..113..764D. doi:10.1086/320802. S2CID   16285959.
  3. 1 2 3 4 5 6 7 8 Evans, A.; et al. (2016). "CK Vul: A smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides)". Monthly Notices of the Royal Astronomical Society. 457 (3): 2871–2876. arXiv: 1512.02146 . Bibcode:2016MNRAS.457.2871E. doi:10.1093/mnras/stw352. S2CID   76657165.
  4. 1 2 3 4 5 6 Banerjee, D. P. K.; Geballe, T. R.; Evans, A.; Shahbandeh, M.; Woodward, C. E.; Gehrz, R. D.; Eyres, S. P. S.; Starrfield, S.; Zijlstra, A. (2020). "Near-infrared Spectroscopy of CK Vulpeculae: Revealing a Remarkably Powerful Blast from the Past". The Astrophysical Journal. 904 (2): L23. arXiv: 2011.02939 . Bibcode:2020ApJ...904L..23B. doi: 10.3847/2041-8213/abc885 . S2CID   226254757.
  5. 1 2 Morton, Wagman (2003). Lost Stars. Blacksburg, Virginia: McDonald and Woodward. p. 494. ISBN   978-0-939923-78-6.
  6. 1 2 3 Shara, M. M.; Moffat, A. F. J.; Webbink, R. F. (July 1, 1985). "Unraveling the oldest and faintest recovered nova - CK Vulpeculae (1670)". Astrophysical Journal. 294: 271–285. Bibcode:1985ApJ...294..271S. doi:10.1086/163296.
  7. ↑ Baily, Francis (1845). The Catalogue of Stars of the British Association for the Advancement of Science. London: Richard and John E Taylor. p. 77. Bibcode:1845tcot.book.....B. ISBN   978-1165133253.
  8. ↑ Shara, M. M.; Moffat, A. F. J. (July 1, 1982). "The recovery of CK Vulpeculae (Nova 1670) - The oldest 'old nova'". Astronomical Journal. 258 (Part 2 Letters to the Editor): L41–L44. Bibcode:1982ApJ...258L..41S. doi: 10.1086/183826 .
  9. ↑ Naylor, T.; Charles, P. A.; Mukai, K.; Evans, A. (1992). "An observational case against nova hibernation". Monthly Notices of the Royal Astronomical Society. 258 (3): 449–456. Bibcode:1992MNRAS.258..449N. doi: 10.1093/mnras/258.3.449 .
  10. 1 2 3 4 5 Hajduk, M.; van Hoof, P. A. M.; Zijlstra, A. A. (11 June 2013). "CK Vul: evolving nebula and three curious background stars". Monthly Notices of the Royal Astronomical Society. 432 (1): 167–175. arXiv: 1312.5846 . Bibcode:2013MNRAS.432..167H. doi:10.1093/mnras/stt426. S2CID   118475362.
  11. ↑ Hajduk, M; Zijlstra, Albert A; Van Hoof, P. A. M; Lopez, J. A; Drew, J. E; Evans, A; Eyres, S. P. S; Gesicki, K; Greimel, R; Kerber, F; Kimeswenger, S; Richer, M. G (2007). "The enigma of the oldest 'nova': The central star and nebula of CK Vul". Monthly Notices of the Royal Astronomical Society. 378 (4): 1298–1308. arXiv: 0709.3746 . Bibcode:2007MNRAS.378.1298H. doi:10.1111/j.1365-2966.2007.11825.x. S2CID   14892116.
  12. 1 2 Kaminski, Tomasz; Menten, Karl M.; Tylenda, Romuald; Hajduk, Marcin; Patel, Nimesh A.; Kraus, Alexander (March 23, 2015). "Nuclear ashes and outflow in the eruptive star Nova Vul 1670". Nature. 520 (7547): 322–4. arXiv: 1503.06570 . Bibcode:2015Natur.520..322K. doi:10.1038/nature14257. PMID   25799986. S2CID   4449518.
  13. ↑ "Stellar Corpse Reveals Origin of Radioactive Molecules - Observations using ALMA find radioactive isotope aluminium-26 from the remnant CK Vulpeculae". www.eso.org. Retrieved 31 July 2018.
  14. ↑ Kamiński, T; Menten, K. M; Tylenda, R; Karakas, A; Belloche, A; Patel, N. A (2017). "Organic molecules, ions, and rare isotopologues in the remnant of the stellar-merger candidate, CK Vulpeculae (Nova 1670)". Astronomy & Astrophysics. 607: A78. arXiv: 1708.02261 . Bibcode:2017A&A...607A..78K. doi:10.1051/0004-6361/201731287. S2CID   62829732.
  15. ↑ Eyres, Stewart; Evans, Aneurin; Zijlstra, Albert; Avison, Adam; Gehrz, Robert; Hajduk, Marcin; Starrfield, Sumner; Mohamed, Shazrene; Woodward, Charles; Wagner, R. Mark (16 September 2018). "ALMA reveals the aftermath of a white dwarf--brown dwarf merger in CK Vulpeculae". Monthly Notices of the Royal Astronomical Society. 481 (4): 4931. arXiv: 1809.05849 . Bibcode:2018MNRAS.481.4931E. doi:10.1093/mnras/sty2554. S2CID   119462149.
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