PV Cephei
| PV Cephei | |
 | |
| Observationsdata Epok: J2000.0 | |
|---|---|
| Stjärnbild | Cepheus[1] |
| Rektascension | 20t 45m 53,943 s[2] |
| Deklination | +67° 57′ 38,66″[2] |
| Skenbar magnitud () | 14,58 - 18,08[3] |
| Stjärntyp | |
| Spektraltyp | A5 Ve[4] |
| Variabeltyp | T Tau[5] |
| Astrometri | |
| Egenrörelse (µ) | RA: +8,228[6] mas/år Dek.: -1,976[6] mas/år |
| Parallax () | 2,910 ± 0,0593[6] |
| Avstånd | 1 120 ± 20 lå (344 ± 7 pc) |
| Detaljer | |
| Massa | 2,6[7] M☉ |
| Radie | 2,9[7] R☉ |
| Luminositet | 1[8] - 100[3] L☉ |
| Temperatur | 8 150[8] K |
| Ålder | <1[3] miljoner år |
| Andra beteckningar | |
| 2MASS J20455394+6757386, IRAS F20453+6746, IRAS 20453+6746, V* PV Cep, Gaia EDR3 2246924068029363840, Gaia DR2 2246924068029363840 [9] | |
PV Cephei är en ensam stjärna i den mellersta delen av stjärnbilden Cepheus. Den har en skenbar magnitud av ca 14,58 – 18,08[3] och kräver ett teleskop för att kunna observeras. Baserat på parallax enligt Gaia Data Release 2 på ca 2,9 mas,[6] beräknas den befinna sig på ett avstånd på ca 1 120 ljusår (ca 344 parsek) från solen.
Egenskaper
PV Cephei är en blå till vit stjärna i huvudserien av spektralklass A5 Ve.[5] Den har en massa som är ca 2,6[7] solmassor, en radie som är ca 2,9[7] solradier och har ungefär samma som solens utstrålning av energi[8] från dess fotosfär vid en effektiv temperatur av ca 8 200 K.[6]
Referenser
- Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, PV Cephei, 24 maj 2022..
Noter
- ^ "A changing fan". ESA/Hubble Picture of the Week. Hämtad 23 april 2013.
- ^ [a b] Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ [a b c d] Kun, M.; Szegedi-Elek, E.; Moór, A.; Kóspál, Á.; Ábrahám, P.; Apai, D.; Kiss, Z. T.; Klagyivik, P.; Magakian, T. Yu.; Mező, Gy.; Movsessian, T. A.; Pál, A.; Rácz, M.; Rogers, J. (2011). "Inner disc rearrangement revealed by dramatic brightness variations in the young star PV Cep". Monthly Notices of the Royal Astronomical Society. 413 (4): 2689. arXiv:1101.2329. Bibcode:2011MNRAS.413.2689K. doi:10.1111/j.1365-2966.2011.18341.x. S2CID 118623750.
- ^ Watson, C. L. (2006). "The International Variable Star Index (VSX)". The Society for Astronomical Sciences 25th Annual Symposium on Telescope Science. Held May 23–25. 25: 47. Bibcode:2006SASS...25...47W.
- ^ [a b] Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ^ [a b c d e] 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 c d] Caratti o Garatti, A.; Garcia Lopez, R.; Weigelt, G.; Tambovtseva, L. V.; Grinin, V. P.; Wheelwright, H.; Ilee, J. D. (2013). "LBT/LUCIFER near-infrared spectroscopy of PV Cephei. An outbursting young stellar object with an asymmetric jet". Astronomy and Astrophysics. 554: A66. arXiv:1304.6267. Bibcode:2013A&A...554A..66C. doi:10.1051/0004-6361/201321418. S2CID 46977755.
- ^ [a b c] Vioque, M.; Oudmaijer, R. D.; Baines, D.; Mendigutía, I.; Pérez-Martínez, R. (2018). "Gaia DR2 study of Herbig Ae/Be stars". Astronomy and Astrophysics. 620: A128. arXiv:1808.00476. Bibcode:2018A&A...620A.128V. doi:10.1051/0004-6361/201832870. S2CID 118928804.
- ^ PV Cephei (unistra.fr) , Hämtad 2022-07-20.
- ^ Lorenzetti, D.; Giannini, T.; Larionov, V. M.; Arkharov, A. A.; Antoniucci, S.; Di Paola, A.; Konstantinova, T. S.; Kopatskaya, E. N.; Li Causi, G.; Nisini, B. (May 2011). "Simultaneous monitoring of the photometric and polarimetric activity of the young star PV Cep in the optical/near-infrared bands". The Astrophysical Journal. 732 (2). doi:10.1088/0004-637X/732/2/69. Hämtad 6 december 2021.
Externa länkar
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Media som används på denna webbplats
Författare/Upphovsman: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg), Licens: CC BY 3.0
IAU Cepheus chart
Författare/Upphovsman: PopePompus, Licens: CC BY-SA 4.0
An R band light curve for PV Cephei, adapted from Lorenzetti et al., The Astrophysical Journal, 732:69 (11pp), 2011 May 10
(c) ESA/Hubble, CC BY 4.0
The Universe is rarely static, although the timescales involved can be very long. Since modern astronomical observations began we have been observing the birthplaces of new stars and planets, searching for and studying the subtle changes that help us to figure out what is happening within.
The bright spot located at the edge of the bluish fan-shaped structure in this Hubble image is a young star called V* PV Cephei, or PV Cep. It is a favourite target for amateur astronomers because the fan-shaped nebulosity, known as GM 1-29 or Gyulbudaghian’s Nebula, changes over a timescale of months. The brightness of the star has also varied over time.
Images of PV Cep taken in 1952 showed a nebulous streak, similar to a comet’s tail. However, these had vanished when new images of the star were obtained some twenty-five years later. Instead, the blue fan-shaped nebula had appeared. Twenty-five years is a very short period on cosmic timescales, so astronomers think that the mysterious streak may have been a temporary phenomenon, such as the remnants of a massive stellar flare — similar to the solar flares we are used to seeing in the Solar System.
At the same time as this was happening, the star itself was brightening. This provided the light to illuminate the newly formed fan-shaped nebula. This brightening might be related to the start of the hydrogen-burning phase of the star, which would mean that it was reaching maturity.
PV Cep is thought to be surrounded by a disc of gas and dust, which would stop light from escaping in all directions. The fan-like appearance is therefore probably a result of starlight escaping from the dust disc and projecting onto the nebula.
PV Cep is located in the northern constellation of Cepheus at a distance of over 1600 light-years from Earth.
A version of this image was entered into the Hubble’s Hidden Treasures competition by contestant Alexey Romashin.