G 29-38

Last updated
G29-38
G29-38 Debris disk.jpg
Artist's impression of G29-38 and its debris disk
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Pisces
Right ascension 23h 28m 47.6365s [1]
Declination +05° 14′ 54.235″ [1]
Apparent magnitude  (V)13.03 [2]
Characteristics
Spectral type DAV4.4 [2]
U−B color index −0.63 [2]
B−V color index 0.14 [2]
V−R color index 0.0 [3]
R−I color index 0.2 [3]
Variable type DAV (ZZ Ceti) [2]
Astrometry
Radial velocity (Rv)15.3 ± 3.0 [3]  km/s
Proper motion (μ)RA: −398.246(32)  mas/yr [1]
Dec.: −266.744(20)  mas/yr [1]
Parallax (π)57.0620 ± 0.0251  mas [1]
Distance 57.16 ± 0.03  ly
(17.525 ± 0.008  pc)
Details
Mass 0.593 ± 0.012 [4]   M☉
Radius 0.01 [5]   R☉
Luminosity (bolometric)0.002 [6]   L☉
Surface gravity (log g)8.15 ± 0.05 [6]   cgs
Temperature 11,820 ± 175 [6]   K
Other designations
ZZ  Piscium, EGGR 159, GJ  895.2, LHS  5405, LTT  16907, NLTT  56992, WD 2326+049. [3]
Database references
SIMBAD data

Giclas 29-38, also known as ZZ Piscium, is a variable white dwarf star of the DAV (or ZZ Ceti) type, whose variability is due to large-amplitude, non-radial pulsations known as gravity waves. It was first reported to be variable by Shulov and Kopatskaya in 1974. [7] [8] DAV stars are like normal white dwarfs but have luminosity variations with amplitudes as high as 30%, arising from a superposition of vibrational modes with periods from 100 to 1,000 seconds. Large-amplitude DAVs generally differ from lower-amplitude DAVs by having lower temperatures, longer primary periodicities, and many peaks in their vibrational spectra with frequencies which are sums of other vibrational modes. [9]

Contents

A light curve for ZZ Piscium, adapted from Fontaine and Brassard (2008) ZZPscLightCurve.png
A light curve for ZZ Piscium, adapted from Fontaine and Brassard (2008)

G29-38, like other complex, large-amplitude DAV variables, has proven difficult to understand. The power spectrum or periodogram of the light curve varies over times which range from weeks to years. Usually, one strong mode dominates, although many smaller-amplitude modes are often observed. The larger-amplitude modes, however, fluctuate in and out of observability; some low-power areas show more stability. Asteroseismology uses the observed spectrum of pulsations from stars like G29-38 to infer the structure of their interiors. [9]

The spectrum of G29-38 G29-38 Spectra.jpg
The spectrum of G29-38

Debris disk

The circumstellar environment of G29-38 first attracted attention in the late 1980s during a near-infrared survey of 200 white dwarfs conducted by Ben Zuckerman and Eric Becklin to search for low mass companion stars and brown dwarfs. [11] G29-38 was shown to radiate substantial emission between 2 and 5 micrometres, far in excess of that expected from extrapolation of the visual and near infrared spectrum of the star. [12] Like other young, hot white dwarfs, G29-38 is thought to have formed relatively recently (600 million years ago) from its AGB progenitor, and therefore the excess was naturally explained by emission from a Jupiter-like brown dwarf with a temperature of 1200 K and a radius of 0.15 solar radius. [11] [12] However, later observations, including speckle interferometry, failed to detect a brown dwarf. [13]

Infrared observations made in 2004 by NASA's Spitzer Space Telescope indicated the presence of a dust cloud around G29-38, which may have been created by tidal disruption of an exocomet or exoasteroid passing close to the white dwarf. [14] This may mean that G29-38 is still orbited by a ring of surviving comets and, possibly, outer planets. This is the first observation supporting the idea that comets persist to the white dwarf stage of stellar evolution. [15]

Infrared emission at 9-11 Mircons from Spitzer spectroscopy were interpreted as a mixture of amorphous olivine and a small amount of fosterite in the disk. [14] Modelling of the disk have shown that the inner edge of the disk lies at around 96±4 white dwarf radii and that the disk has a width of about 1-10 white dwarf radii. The dust mass of the disk is about 4-5 x 1018 g (about half the mass of a massive asteroid) and the disk has a temperature less than 1000 K. [16]

The white dwarf is detected in x-rays with Chandra and XMM-Newton. This is seen as evidence for accretion from the disk and while the count number is small, there is evidence that this x-ray emission could come from iron. [17]

Related Research Articles

<span class="mw-page-title-main">White dwarf</span> Type of stellar remnant composed mostly of electron-degenerate matter

A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to Earth's. A white dwarf's low luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Jacob Luyten in 1922.

<span class="mw-page-title-main">Brown dwarf</span> Type of substellar object larger than a planet

Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. Their mass is approximately 13 to 80 times that of Jupiter (MJ)—not big enough to sustain nuclear fusion of ordinary hydrogen (1H) into helium in their cores, but massive enough to emit some light and heat from the fusion of deuterium (2H). The most massive ones can fuse lithium (7Li).

<span class="mw-page-title-main">2M1207</span> Brown dwarf in the constellation Centaurus

2M1207, 2M1207A or 2MASS J12073346–3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first extrasolar planetary-mass companion to be directly imaged, and is the first discovered orbiting a brown dwarf.

<span class="mw-page-title-main">AU Microscopii</span> Star in the constellation Microscopium

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Eta Telescopii is a white-hued star in the southern constellation of Telescopium. This is an A-type main sequence star with an apparent visual magnitude of +5.03. It is approximately 158 light years from Earth and is a member of the Beta Pictoris Moving Group of stars that share a common motion through space. It forms a wide binary system with the star HD 181327 and has a substellar companion orbiting around it, named Eta Telescopii B.

<span class="mw-page-title-main">NGC 2547</span> Open cluster in the constellation Vela

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<span class="mw-page-title-main">HL Tau 76</span> Star in the constellation Taurus

HL Tau 76 is a variable white dwarf star of the DAV type. It was observed by G. Haro and W. J. Luyten in 1961, and was the first variable white dwarf discovered when, in 1968, Arlo U. Landolt found that it varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes. Like other DAV white dwarfs, its variability arises from non-radial gravity wave pulsations within itself., § 7. Later observation and analysis has found HL Tau 76 to pulsate in over 40 independent vibrational modes, with periods between 380 seconds and 1390 seconds.

A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA; DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB; and GW Vir stars, with atmospheres dominated by helium, carbon, and oxygen, and the spectral type PG 1159. GW Vir stars may be subdivided into DOV and PNNV stars; they are not, strictly speaking, white dwarfs but pre-white dwarfs which have not yet reached the white dwarf region on the Hertzsprung-Russell diagram. A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed, and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.

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Ross 548 is a white dwarf in the equatorial constellation of Cetus. With a mean apparent visual magnitude of 14.2 it is much too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of 107 light years from the Sun. It was found to be variable in 1970 and in 1972 it was given the variable star designation ZZ Ceti. This is a pulsating white dwarf of the DAV type that is the prototype of the ZZ Ceti variable class., pp. 891, 895.

<span class="mw-page-title-main">GD 362</span> Star in the constellation Hercules

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<span class="mw-page-title-main">GD 66</span> Star in the constellation Auriga

GD 66 or V361 Aurigae is a 0.64 solar mass (M☉) pulsating white dwarf star located 170 light years from Earth in the Auriga constellation. The estimated cooling age of the white dwarf is 500 million years. Models of the relationship between the initial mass of a star and its final mass as a white dwarf star suggest that when the star was on the main sequence it had a mass of approximately 2.5 M☉, which implies its lifetime was around 830 million years. The total age of the star is thus estimated to be in the range 1.2 to 1.7 billion years.

HD 210277 b is an extrasolar planet orbiting the star HD 210277. It was discovered in September 1998 by the California and Carnegie Planet Search team using the highly successful radial velocity method. The planet is at least 24% more massive than Jupiter. The mean distance of the planet from the star is slightly more than Earth's distance from the Sun. However, the orbit is very eccentric, so at periastron this distance is almost halved, and at apastron it is as distant as Mars is from the Sun.

<span class="mw-page-title-main">HR 8799</span> Star in the constellation Pegasus

HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. These planets were the first exoplanets whose orbital motion was confirmed by direct imaging. The star is a Gamma Doradus variable: its luminosity changes because of non-radial pulsations of its surface. The star is also classified as a Lambda Boötis star, which means its surface layers are depleted in iron peak elements. It is the only known star which is simultaneously a Gamma Doradus variable, a Lambda Boötis type, and a Vega-like star.

<span class="mw-page-title-main">GD 165</span> Star in the constellation Boötes

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<span class="mw-page-title-main">HD 115600</span> Star in the constellation Centaurus

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<span class="mw-page-title-main">LSPM J0207+3331</span> Star in the constellation Taurus

LSPM J0207+3331 is a cold and old white dwarf that hosts a circumstellar disk, located 145 light-years from Earth. It was discovered in October 2018 by a volunteer participating in the Backyard Worlds citizen science project. Until 2021 it was the oldest and coldest white dwarf known to host a disk. The white dwarf WD 2317+1830 with a detected disk is at least twice as old and around 2,000 K colder.

<span class="mw-page-title-main">WD 0145+234</span> White dwarf in the constellation Aries

WD 0145+234 is a white dwarf star approximately 95 ly (29 pc) from Earth in the constellation of Aries that has been associated with studies suggesting that a very large exoasteroid near the star was substantially disrupted, resulting in a considerable amount of dust and debris around the star. Alternatively, the outburst around WD 0145+234 is explained with ongoing collisions between planetesimals inside the dusty debris disk around the white dwarf.

<span class="mw-page-title-main">Exoasteroid</span> Asteroids found outside of the Solar System

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References

  1. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 5 The general catalogue of trigonometric parallaxes, W. F. van Altena, J. T. Lee, E. D. Hoffleit, New Haven, CT: Yale University Observatory, c1995, 4th ed., completely revised and enlarged. CDS ID I/238A.
  3. 1 2 3 4 "V* ZZ Psc". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved December 11, 2008.
  4. ↑ Kirkpatrick, J. Davy; Marocco, Federico; Gelino, Christopher R.; Raghu, Yadukrishna; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella C.; Schurr, Steven D.; Apps, Kevin; Schneider, Adam C.; Meisner, Aaron M.; Kuchner, Marc J.; Caselden, Dan; Smart, R. L.; Casewell, S. L.; Raddi, Roberto (2024-04-01). "The Initial Mass Function Based on the Full-sky 20 pc Census of ∼3600 Stars and Brown Dwarfs". The Astrophysical Journal Supplement Series. 271 (2): 55. Bibcode:2024ApJS..271...55K. doi: 10.3847/1538-4365/ad24e2 . ISSN   0067-0049.
  5. ↑ §1, The Dust cloud around the White Dwarf G 29-38. 2. Spectrum from 5-40 microns and mid-infrared variability, William T. Reach, Carey Lisse, Ted von Hippel, and Fergal Mullally, Astrophysical Journal, in press, Bibcode:2008arXiv0810.3276R.
  6. 1 2 3 Table 1, The Formation Rate and Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey, James Liebert, P. Bergeron, and J. B. Holberg, The Astrophysical Journal Supplement Series156, #1 (January 2005), pp. 47–68, doi:10.1086/425738, Bibcode:2005ApJS..156...47L.
  7. ↑ O. S. Shulov and E. N. Kopatskaya, Astrofizika10, #1 (January–March, 1974), pp. 117–120. Translated into English as Variability of the white dwarf G 29-38, Astrophysics, 10, #1 (January, 1974), pp. 72–74. DOI 10.1007/BF01005183.
  8. ↑ G 29-38 and G 38-29: two new large-amplitude variable white dwarfs, J. T. McGraw and E. L. Robinson, Astrophysical Journal200 (September 1975), pp. L89–L93.
  9. 1 2 Observational limits on companions to G29-38, S. J. Kleinman, R. E. Nather, D. E. Winget, J. C. Clemens, P. A. Bradley, A. Kanaan, J. L. Provencal, C. F. Claver, T. K. Watson, K. Yanagida, J. S. Dixson, M. A. Wood, D. J. Sullivan, E. Meistas, E. M. Leibowitz, P. Moskalik, S. Zola, G. Pajdosz, J. Krzesinski, J.-E. Solheim, A. Bruvold, D. O'Donoghue, M. Katz, G. Vauclair, N. Dolez, M. Chevreton, M. A. Barstow, S. O. Kepler, O. Giovannini, C. J. Hansen, and S. D. Kawaler, Astrophysical Journal436, #2 (December 1994), pp. 875–884.
  10. ↑ Fontaine, G.; Brassard, P. (October 2008). "The Pulsating White Dwarf Stars". Publications of the Astronomical Society of the Pacific. 120 (872): 1043. Bibcode:2008PASP..120.1043F. doi: 10.1086/592788 . S2CID   119685025.
  11. 1 2 A low-temperature companion to a white dwarf star, E. E. Becklin & B. Zuckerman, Nature336 (Dec. 15, 1988), pp. 656-658
  12. 1 2 Excess infrared radiation from a white dwarf - an orbiting brown dwarf? B. Zuckerman & E. E. Becklin, Nature330, (Nov. 12, 1987), pp. 138-140
  13. ↑ Keck Speckle Imaging of the White Dwarf G29-38: No Brown Dwarf Companion Detected, Marc J. Kuchner, Christopher D. Koresko, and Michael E. Brown, The Astrophysical Journal508, #1 (November 20, 1998), pp. L81–L83. doi : 10.1086/311725. Bibcode : 1998ApJ...508L..81K.
  14. 1 2 The Dust Cloud around the White Dwarf G29-38, William T. Reach, Marc J. Kuchner, Ted von Hippel, Adam Burrows, Fergal Mullally, Mukremin Kilic, and D. E. Winget, Astrophysical Journal635, #2 (December 2005), pp. L161–L164.
  15. ↑ NASA's Spitzer Finds Possible Comet Dust Around Dead Star Archived 2006-02-17 at the Wayback Machine , NASA press release, January 11, 2006.
  16. ↑ Ballering, Nicholas P.; Levens, Colette I.; Su, Kate Y. L.; Cleeves, L. Ilsedore (2022-11-01). "The Geometry of the G29-38 White Dwarf Dust Disk from Radiative Transfer Modeling". The Astrophysical Journal. 939 (2): 108. arXiv: 2211.00118 . Bibcode:2022ApJ...939..108B. doi: 10.3847/1538-4357/ac9a4a . ISSN   0004-637X.
  17. ↑ Estrada-Dorado, S.; Guerrero, M. A.; Toalá, J. A.; Chu, Y. -H.; Lora, V.; Rodríguez-López, C. (2023-02-01). "XMM-Newton Detection of X-Ray Emission from the Metal-polluted White Dwarf G 29-38". The Astrophysical Journal. 944 (2): L46. arXiv: 2302.05028 . Bibcode:2023ApJ...944L..46E. doi: 10.3847/2041-8213/acba7e . ISSN   0004-637X.
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