// Workers AI · dad joke modeWhat did GD 358 say to its star friend? You're a-maize-ing.
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Hercules |
| Right ascension | 16h 47m 19.02s[2] |
| Declination | +32° 28′ 31.9″[2] |
| Apparent magnitude (V) | 13.65[2] |
| Characteristics | |
| Evolutionary stage | white dwarf[3] |
| Spectral type | DBV2[3] |
| B−V color index | -0.1[2] |
| Variable type | DBV[3] |
| Astrometry | |
| Proper motion (μ) | RA: 6[2] mas/yr Dec.: -162[2] mas/yr |
| Parallax (π) | 23.2012±0.0298 mas[4] |
| Distance | 140.6 ± 0.2 ly (43.10 ± 0.06 pc) |
| Absolute magnitude (MV) | +10.33[5] |
| Details[6] | |
| Mass | 0.584+0.025 −0.019 M☉ |
| Radius | 0.0132±0.0004 R☉ |
| Radius | 9,170+300 −290 km |
| Luminosity | 0.061±0.002 L☉ |
| Surface gravity (log g) | 7.964+0.048 −0.043 cgs |
| Temperature | 24,967±200 K |
| Other designations | |
| EGGR 239, V777 Her, PG 1645+325, WD 1645+325. | |
| Database references | |
| SIMBAD | data |
GD 358 is a variable white dwarf star of the DBV type. Like other pulsating white dwarfs, its variability arises from non-radial gravity wave pulsations within the star itself.[7] GD 358 was discovered during the 1958–1970 Lowell Observatory survey for high proper motion stars in the Northern Hemisphere.[8] Although it did not have high proper motion, it was noticed that it was a very blue star, and hence might be a white dwarf.[9] Greenstein confirmed this in 1969.[10]
In 1968, Arlo U. Landolt discovered the first intrinsically variable white dwarf when he found that HL Tau 76 varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes.[11] By the middle of the 1970s, a number of additional variable white dwarfs had been found, but, like HL Tau 76, they were all white dwarfs of spectral type DA, with hydrogen-dominated atmospheres.[12][13][14] In 1982, calculations by Don Winget and his coworkers suggested that helium-atmosphere DB white dwarfs with surface temperatures around 19,000 K should also pulsate.[15] Winget then searched for such stars and found that GD 358 was a variable DB, or DBV, white dwarf.[1] This was the first prediction of a class of variable stars before their observation.[16], p. 89. In 1985, this star was given the variable-star designation V777 Herculis, which is also another name for this class of variable stars.[17]; [18]
Notes and references
[edit]- 1 2 Winget, D. E.; Robinson, E. L.; Nather, R. E.; Fontaine, G. (1982-11-01). "Photometric observations of GD 358 : OB white dwarfs do pulsate". The Astrophysical Journal. 262: L11–L15. Bibcode:1982ApJ...262L..11W. doi:10.1086/183902. ISSN 0004-637X.
- 1 2 3 4 5 6 "GD 358". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 12, 2007.
- 1 2 3 McCook, George P.; Sion, Edward M. (1999). "A Catalog of Spectroscopically Identified White Dwarfs". The Astrophysical Journal Supplement Series. 121 (1): 1. Bibcode:1999ApJS..121....1M. doi:10.1086/313186. III/210
- ↑ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ↑ Limoges, M. -M; Bergeron, P.; Lépine, S. (2015). "Physical Properties of the Current Census of Northern White Dwarfs within 40 pc of the Sun". The Astrophysical Journal Supplement Series. 219 (2): 19. arXiv:1505.02297. Bibcode:2015ApJS..219...19L. doi:10.1088/0067-0049/219/2/19. S2CID 118494290.
- ↑ Córsico, A. H.; Uzundag, M.; Kepler, S. O.; Silvotti, R.; Althaus, L. G.; Koester, D.; Baran, A. S.; Bell, K. J.; Bischoff-Kim, A.; Hermes, J. J.; Kawaler, S. D.; Provencal, J. L.; Winget, D. E.; Montgomery, M. H.; Bradley, P. A.; Kleinman, S. J.; Nitta, A. (2022). "Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS. III. Asteroseismology of the DBV star GD 358". Astronomy & Astrophysics. 659: A30. arXiv:2111.15551. Bibcode:2022A&A...659A..30C. doi:10.1051/0004-6361/202142153. S2CID 244729212.
- ↑ Winget, D E (1998-12-14). "Asteroseismology of white dwarf stars". Journal of Physics: Condensed Matter. 10 (49): 11247–11261. Bibcode:1998JPCM...1011247W. doi:10.1088/0953-8984/10/49/014. ISSN 0953-8984. S2CID 250749380.
- ↑ Giclas, H. L.; Burnham, R.; Thomas, N. G. (1971). Lowell proper motion survey Northern Hemisphere. The G numbered stars. 8991 stars fainter than magnitude 8 with motions > 0".26/Year. Bibcode:1971lpms.book.....G. I/79
- ↑ Giclas, Henry L.; Burnham, Robert; Thomas, Norman Gene (1967). "A list of white dwarf suspects II : Special objects of small proper motion from the Lowell survey". Lowell Observatory Bulletin. 7 (141): 49. Bibcode:1967LowOB...7...49G.
- ↑ Greenstein, Jesse L. (1969). "The Lowell Suspect White Dwarfs". The Astrophysical Journal. 158: 281. Bibcode:1969ApJ...158..281G. doi:10.1086/150191.
- ↑ Landolt, Arlo U. (1968). "A New Short-Period Blue Variable". The Astrophysical Journal. 153: 151. Bibcode:1968ApJ...153..151L. doi:10.1086/149645.
- ↑ Robinson, E. L.; McGraw, J. T. (1976). "Observations of variable white dwarfs: One new variable and 35 nonvariables". The Astrophysical Journal. 207: L37. Bibcode:1976ApJ...207L..37R. doi:10.1086/182173.
- ↑ Hesser, J. E.; Lasker, B. M.; Neupert, H. E. (1976). "High-frequency stellar oscillations. XI. The ZZ Ceti star BPM 30551". The Astrophysical Journal. 209: 853. Bibcode:1976ApJ...209..853H. doi:10.1086/154784.
- ↑ McGraw, J. T. (1976). "BPM 31594: A new southern-hemisphere variable white dwarf". The Astrophysical Journal. 210: L35. Bibcode:1976ApJ...210L..35M. doi:10.1086/182297.
- ↑ Winget, D. E.; Van Horn, H. M.; Tassoul, M.; Fontaine, G.; Hansen, C. J.; Carroll, B. W. (1982). "Hydrogen-driving and the blue edge of compositionally stratified ZZ Ceti star models". The Astrophysical Journal. 252: L65. Bibcode:1982ApJ...252L..65W. doi:10.1086/183721.
- ↑ Kawaler, Steven D. (1997). "White Dwarf Stars". Stellar Remnants. Saas-Fee Advanced Courses. Vol. 25. pp. 1–95. doi:10.1007/3-540-31628-0_1. ISBN 3-540-61520-2.
- ↑ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1. Bibcode:1985IBVS.2681....1K.
- ↑ Fontaine, G.; Wesemael, F. (2000). White Dwarfs. Bibcode:2000eaa..bookE1894F.
