Gyulbudaghian's Nebula (gyool-boo-DAH-ghee-an) is a reflection nebula in the northern constellation Cepheus, located about 1.5 degrees west of the much brighter reflection nebula NGC 7023. The light illuminating it comes from the T Tauri star PV Cephei. It is known for changing its shape dramatically on a timescale of months to years, as the brightness of PV Cephei changes.[4] The nebula, whose magnitude ranges from 13.4 to 18.5,[3] is far too faint to be seen with the naked eye, or even a small telescope. However, because of its changing morphology, it has become a target for observations by advanced amateur astronomers.[5][6]
| Reflection nebula | |
|---|---|
 HST image | |
| Observation data: J2000 epoch | |
| Right ascension | 20h 45m 54s[1] |
| Declination | 67° 57′ 00″[1] |
| Distance | 1,109[2] ly |
| Apparent magnitude (V) | 13.4 - 18.5[3] |
| Apparent dimensions (V) | 1.5 × 1.0′[3] |
| Constellation | Cepheus |
| Designations | GM 1-29 |
Gyulbudaghian's Nebula was discovered in 1977 by Armenian astronomers Armen Gyul'budaghian and Tigran Yu. Magakian at the Byurakan Astrophysical Observatory[7] and separately that same year by Martin Cohen, Leonard Vello Kuhi and Eugene A. Harlan in California.[8] Both groups discovered the nebula on the red Palomar Sky Survey (POSS) plates taken in 1952. Gyul'budaghian's group discovered the nebula's variable nature from followup observations with the 2.6 meter Byurakan reflector, and Cohen's group discovered its variability by comparing the POSS images with images of the region taken over a five-year period at Lick Observatory.[4] It was found that the nebula sometimes appeared as a streak, and at other times it was shaped like a fan with PV Cephei at its tip.[4] Subsequent studies have shown that sometimes the nebula nearly disappears completely.[3]
In 1986 Scarrott et al. reported that Gyulbudaghian's Nebula is either bipolar or biconical. In addition to the fan shaped nebulousity to the north of PV Cephei, seen by earlier observers, they detected a fainter counterlobe south of the star. From polarization measurements they concluded that the bright north lobe is not reflected light, but rather intrinsic emission.[9] The faint southern counterlobe was later found to be quite red; it is brighter in the near-infrared than in visible light and is dimmed by at least 4 magnitudes of extinction in visible light.[10] The streak, when it is visible, coincides with the eastern edge of the fan-shaped nebula.[11]
References
edit- ^ a b "GM 1-29". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2024-10-15.
- ^ Saha, p.; Maheswar, G.; Mathew, B.; Kamath, U. S. (September 2021). "Star formation around three co-moving HAeBe stars in the Cepheus Flare". Astronomy & Astrophysics. 653: A142. Bibcode:2021A&A...653A.142S. doi:10.1051/0004-6361/202039646. Retrieved 27 October 2024.
- ^ a b c d Privett, Grant; Tasselli, Andrea; Luck, Andrew; Garner, Bob; Holt; Self, Daniel; Thurston, Geoff; Harlow, Mike; Brazell, Owen; Goldsmith, Steven (October 2019). "The many faces of Gyulbudaghian's Nebula". Journal of the British Astronomical Association. 129 (5): 273–277. Bibcode:2019JBAA..129..273P. Retrieved 22 October 2024.
- ^ a b c Cohen, M.; Kuhi, L. V.; Harlan, E. A. (August 1977). "A remarkable structural change in a faint cometary nebula". Astrophysical Journal. 215: L127–L129. Bibcode:1977ApJ...215L.127C. doi:10.1086/182494. Retrieved 13 October 2024.
- ^ "Gyulbudaghian's nebula". British Astronomical Association. Retrieved 22 October 2024.
- ^ Goodman, Alyssa A.; Arce, Héctor G. (June 2004). "PV Cephei: Young Star Caught Speeding?". The Astrophysical Journal. 608 (2): 831–845. arXiv:astro-ph/0401486. Bibcode:2004ApJ...608..831G. doi:10.1086/383139. Retrieved 23 October 2024.
- ^ Gyul'budagyan, A. L.; Magakyan, T. Yu.; Amirkhanyan, A. S. (April 1977). "Conspicuous changes in the shape of two cometary nebulae". Soviet Astronomy Letters. 3: 162–164. Retrieved 23 October 2024.
- ^ Gledhill, T. M.; Warren-Smith, R. F.; Scarrott, S. M. (December 1987). "Optical imaging and polarization mapping of the variable nebulosity associated with the PMS star PV Cephei". Monthly Notices of the Royal Astronomical Society. 229 (4): 643–652. Bibcode:1987MNRAS.229..643G. doi:10.1093/mnras/229.4.643.
- ^ Scarrott, S. M.; Warren-Smith, R. F.; Draper, P. W.; Gledhill, T. M. (April 1986). "Optical polarimetry of nebulae in regions of star formation". Canadian Journal of Physics. 64 (4): 426–430. Bibcode:1986CaJPh..64..426S. doi:10.1139/p86-076. Retrieved 23 October 2024.
- ^ Levreault, Russell M.; Opal, Chet B. (March 1987). "CCD Observations of the Counterfan in PV Cephei". Astronomical Journal. 93 (3): 669–671. Bibcode:1987AJ.....93..669L. doi:10.1086/114349. Retrieved 23 October 2024.
- ^ Gomez, Mercedes; Kenyon, Scott J.; Whitney, Barbara A. (July 1997). "The Bipolar Optical Outflow Associated with PV Cephei". Astronomical Journal. 114 (1): 265–271. Bibcode:1997AJ....114..265G. doi:10.1086/118471. Retrieved 23 October 2024.
External links
edit- A movie showing the nebula changing shape made from Zwicky Transient Facility images