G 29-38

G29-38

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]
Distance57.16 ± 0.03 ly
(17.525 ± 0.008 pc)
Details
Mass0.593 ± 0.012[4] M☉
Radius0.01[5] R☉
Luminosity (bolometric)0.002[6] L☉
Surface gravity (log g)8.15 ± 0.05[6] cgs
Temperature11,820 ± 175[6] K
Other designations
ZZ Piscium, EGGR 159, GJ 895.2, LHS 5405, LTT 16907, NLTT 56992, WD 2326+049.[3]
Database references
SIMBADdata

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]

A light curve for ZZ Piscium, adapted from Fontaine and Brassard (2008)[10]

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
  1. ^ a b c d Cite error: The named reference Gaia DR3 was invoked but never defined (see the help page).
  2. ^ a b c d e 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. ^ a b c d "V* ZZ Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 11, 2008.
  4. ^ Cite error: The named reference kirkpatrick was invoked but never defined (see the help page).
  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. ^ a b c 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 Series 156, #1 (January 2005), pp. 47–68, doi:10.1086/425738, Bibcode:2005ApJS..156...47L.
  7. ^ O. S. Shulov and E. N. Kopatskaya, Astrofizika 10, #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 Journal 200 (September 1975), pp. L89–L93.
  9. ^ a b 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 Journal 436, #2 (December 1994), pp. 875–884.
  10. ^ Cite error: The named reference Fontaine was invoked but never defined (see the help page).