| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 19h 00m 10.2534s [1] |
| Declination | +70° 39′ 51.418″ [1] |
| Apparent magnitude (V) | 13.19 [2] |
| Characteristics | |
| Spectral type | DAP4.5 [3] |
| U−B color index | -0.85 [4] |
| B−V color index | +0.05 [4] |
| Astrometry | |
| Proper motion (μ) |
RA: +85.774
[1]
mas/
yr Dec.: +505.050 [1] mas/ yr |
| Parallax (π) | 77.6525 ± 0.0317 mas [1] |
| Distance | 42.00 ± 0.02
ly (12.878 ± 0.005 pc) |
| Details [5] | |
| Mass | 1.029 M☉ |
| Radius | 5,960 [a] km |
| Luminosity | 0.013182 L☉ |
| Surface gravity (log g) | 8.67 cgs |
| Temperature | 12540±143 K |
| Age | (as white dwarf) 1.138 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
GRW +70 8247 is a white dwarf star located 42 light-years from Earth [1] in the constellation Draco. With a magnitude of about 13 it is visible only through a large telescope.
Properties
Although photographed in the 19th century as part of the Carte du Ciel project, the star was not determined to be a white dwarf until G. P. Kuiper observed it in 1934. [7] This makes it the fifth or sixth white dwarf discovered. [b] At first, its spectrum was thought to be almost featureless, [7] but later observation showed it to have unusual broad, shallow absorption bands. [11] [12] In 1970, when light that it emitted was observed to be circularly polarized, it became the first white dwarf known to have a magnetic field. [13] [14] In the 1980s, it was realized that the unusual absorption bands could be explained as hydrogen absorption lines shifted by the Zeeman effect. [6] [15] [16]
Notes
-
^ Applying the
Stefan–Boltzmann law with a nominal
solar
effective temperature of 5,772
K:
- .
- ^ The star EGGR 37 was suspected to be a white dwarf by April 1934, [8] but this was not confirmed until 1938. [9] [10]
References
- ^ a b c d e f 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.
- ^ a b "LAWD 73". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 5, 2007.
- ^ Wesemael, F.; Greenstein, J. L.; Liebert, James; Lamontagne, R.; Fontaine, G.; Bergeron, P.; Glaspey, J. W. (1993). "An atlas of optical spectra of white-dwarf stars". Publications of the Astronomical Society of the Pacific. 105: 761. Bibcode: 1993PASP..105..761W. doi: 10.1086/133228. S2CID 122605705.
- ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ^ "GJ 742". Montreal White Dwarf Database. Retrieved 2024-05-30.
- ^
a
b Jesse L. Greenstein, Ronald J. W. Henry, and R. F. O'Connell (February 15, 1985).
"Further identifications of hydrogen in Grw +70°8247". Astrophysical Journal. 289: L25–L29.
Bibcode:
1985ApJ...289L..25G.
doi:
10.1086/184427.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ a b G. P. Kuiper (October 1934). "Two New White Dwarfs of Large Parallax". Publications of the Astronomical Society of the Pacific. 46 (273): 287–290. Bibcode: 1934PASP...46..287K. doi: 10.1086/124496. S2CID 123421818.
- ^ P. J. van Rhijn and J. J. Raimond (April 1934). "Some new members of the Hyades cluster". Monthly Notices of the Royal Astronomical Society. 94 (6): 508–518, at p. 517. Bibcode: 1934MNRAS..94..508V. doi: 10.1093/mnras/94.6.508.
- ^ Jöran M. Ramberg (May 1938). "Zwei weiße Zwerge unter den physischen Hyadenmigliedern". Astronomische Nachrichten (in German). 265 (6–7): 111–112. Bibcode: 1938AN....265..111R. doi: 10.1002/asna.19382650609.
- ^ See also Gerard P. Kuiper (August 1941). "List of Known White Dwarfs". Publications of the Astronomical Society of the Pacific. 53 (314): 248–252. Bibcode: 1941PASP...53..248K. doi: 10.1086/125335. S2CID 123040354.
- ^ Walter S. Adams and Frederick H. Seahes (1938). "Annual Report of the Director of the Mount Wilson Observatory (1937-1938)". Mount Wilson Observatory Annual Report. 10: 28. Bibcode: 1938MWOAR..10....1A.
- ^ Jesse L. Greenstein and Mildred S. Matthews (July 1957). "Studies of the White Dwarfs. I. Broad Features in White Dwarf Spectra". Astrophysical Journal. 126: 14–18. Bibcode: 1957ApJ...126...14G. doi: 10.1086/146364.
-
^ James C. Kemp, John B. Swedlund, J. D. Landstreet, and J. R. P. Angel (August 1970).
"Discovery of Circularly Polarized Light from a White Dwarf". Astrophysical Journal. 161: L77–L79.
Bibcode:
1970ApJ...161L..77K.
doi:
10.1086/180574.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ Angel, J.R.P.; Landstreet, J.D.; Oke, J.B. (1972). "The Spectral Dependence of Circular Polarization in Grw+70°8247". Astrophysical Journal. 171: L11–L15. Bibcode: 1972ApJ...171L..11A. doi: 10.1086/180857.
-
^ J. R. P. Angel, James Liebert, and H. S. Stockman (May 1, 1985).
"The optical spectrum of hydrogen at 160-350 million gauss in the white dwarf Grw +70°8247". Astrophysical Journal. 292: 260–266.
Bibcode:
1985ApJ...292..260A.
doi:
10.1086/163156.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ D. T. Wickramasinghe and Lilia Ferrario (April 1, 1988). "A centered dipole model for the high field magnetic white dwarf GRW +70°8247". Astrophysical Journal. 327: 222–233. Bibcode: 1988ApJ...327..222W. doi: 10.1086/166184.
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| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 19h 00m 10.2534s [1] |
| Declination | +70° 39′ 51.418″ [1] |
| Apparent magnitude (V) | 13.19 [2] |
| Characteristics | |
| Spectral type | DAP4.5 [3] |
| U−B color index | -0.85 [4] |
| B−V color index | +0.05 [4] |
| Astrometry | |
| Proper motion (μ) |
RA: +85.774
[1]
mas/
yr Dec.: +505.050 [1] mas/ yr |
| Parallax (π) | 77.6525 ± 0.0317 mas [1] |
| Distance | 42.00 ± 0.02
ly (12.878 ± 0.005 pc) |
| Details [5] | |
| Mass | 1.029 M☉ |
| Radius | 5,960 [a] km |
| Luminosity | 0.013182 L☉ |
| Surface gravity (log g) | 8.67 cgs |
| Temperature | 12540±143 K |
| Age | (as white dwarf) 1.138 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
GRW +70 8247 is a white dwarf star located 42 light-years from Earth [1] in the constellation Draco. With a magnitude of about 13 it is visible only through a large telescope.
Properties
Although photographed in the 19th century as part of the Carte du Ciel project, the star was not determined to be a white dwarf until G. P. Kuiper observed it in 1934. [7] This makes it the fifth or sixth white dwarf discovered. [b] At first, its spectrum was thought to be almost featureless, [7] but later observation showed it to have unusual broad, shallow absorption bands. [11] [12] In 1970, when light that it emitted was observed to be circularly polarized, it became the first white dwarf known to have a magnetic field. [13] [14] In the 1980s, it was realized that the unusual absorption bands could be explained as hydrogen absorption lines shifted by the Zeeman effect. [6] [15] [16]
Notes
-
^ Applying the
Stefan–Boltzmann law with a nominal
solar
effective temperature of 5,772
K:
- .
- ^ The star EGGR 37 was suspected to be a white dwarf by April 1934, [8] but this was not confirmed until 1938. [9] [10]
References
- ^ a b c d e f 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.
- ^ a b "LAWD 73". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 5, 2007.
- ^ Wesemael, F.; Greenstein, J. L.; Liebert, James; Lamontagne, R.; Fontaine, G.; Bergeron, P.; Glaspey, J. W. (1993). "An atlas of optical spectra of white-dwarf stars". Publications of the Astronomical Society of the Pacific. 105: 761. Bibcode: 1993PASP..105..761W. doi: 10.1086/133228. S2CID 122605705.
- ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ^ "GJ 742". Montreal White Dwarf Database. Retrieved 2024-05-30.
- ^
a
b Jesse L. Greenstein, Ronald J. W. Henry, and R. F. O'Connell (February 15, 1985).
"Further identifications of hydrogen in Grw +70°8247". Astrophysical Journal. 289: L25–L29.
Bibcode:
1985ApJ...289L..25G.
doi:
10.1086/184427.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ a b G. P. Kuiper (October 1934). "Two New White Dwarfs of Large Parallax". Publications of the Astronomical Society of the Pacific. 46 (273): 287–290. Bibcode: 1934PASP...46..287K. doi: 10.1086/124496. S2CID 123421818.
- ^ P. J. van Rhijn and J. J. Raimond (April 1934). "Some new members of the Hyades cluster". Monthly Notices of the Royal Astronomical Society. 94 (6): 508–518, at p. 517. Bibcode: 1934MNRAS..94..508V. doi: 10.1093/mnras/94.6.508.
- ^ Jöran M. Ramberg (May 1938). "Zwei weiße Zwerge unter den physischen Hyadenmigliedern". Astronomische Nachrichten (in German). 265 (6–7): 111–112. Bibcode: 1938AN....265..111R. doi: 10.1002/asna.19382650609.
- ^ See also Gerard P. Kuiper (August 1941). "List of Known White Dwarfs". Publications of the Astronomical Society of the Pacific. 53 (314): 248–252. Bibcode: 1941PASP...53..248K. doi: 10.1086/125335. S2CID 123040354.
- ^ Walter S. Adams and Frederick H. Seahes (1938). "Annual Report of the Director of the Mount Wilson Observatory (1937-1938)". Mount Wilson Observatory Annual Report. 10: 28. Bibcode: 1938MWOAR..10....1A.
- ^ Jesse L. Greenstein and Mildred S. Matthews (July 1957). "Studies of the White Dwarfs. I. Broad Features in White Dwarf Spectra". Astrophysical Journal. 126: 14–18. Bibcode: 1957ApJ...126...14G. doi: 10.1086/146364.
-
^ James C. Kemp, John B. Swedlund, J. D. Landstreet, and J. R. P. Angel (August 1970).
"Discovery of Circularly Polarized Light from a White Dwarf". Astrophysical Journal. 161: L77–L79.
Bibcode:
1970ApJ...161L..77K.
doi:
10.1086/180574.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ Angel, J.R.P.; Landstreet, J.D.; Oke, J.B. (1972). "The Spectral Dependence of Circular Polarization in Grw+70°8247". Astrophysical Journal. 171: L11–L15. Bibcode: 1972ApJ...171L..11A. doi: 10.1086/180857.
-
^ J. R. P. Angel, James Liebert, and H. S. Stockman (May 1, 1985).
"The optical spectrum of hydrogen at 160-350 million gauss in the white dwarf Grw +70°8247". Astrophysical Journal. 292: 260–266.
Bibcode:
1985ApJ...292..260A.
doi:
10.1086/163156.
{{ cite journal}}: CS1 maint: multiple names: authors list ( link) - ^ D. T. Wickramasinghe and Lilia Ferrario (April 1, 1988). "A centered dipole model for the high field magnetic white dwarf GRW +70°8247". Astrophysical Journal. 327: 222–233. Bibcode: 1988ApJ...327..222W. doi: 10.1086/166184.
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| This article about a white dwarf is a stub. You can help Wikipedia by expanding it. |