SN 2011dh
Encyclopedia
SN 2011dh is a supernova
in the Whirlpool Galaxy
(M51). On 31 May 2011 an apparent magnitude
13.5 type II supernova
(the explosion of a single massive star) was detected in M51 at coordinates 13:30:05.08 +47:10:11.2. It was discovered by Amédée Riou and confirmed by several sources, including the Palomar Transient Factory
. A candidate progenitor has been detected in Hubble Space Telescope
images at coordinates 13:30:05.119 +47:10:11.55. The progenitor may have been a highly luminous yellow supergiant
with an initial mass of 18-24 solar mass
es. The supernova appears to have peaked near apparent magnitude
12.1 on 19 June 2011.
Emission spectra
from W. M. Keck Observatory, obtained by Palomar Transient Factory indicate that this is a type II supernova
with a relatively blue continuum with P Cygni
profiles in the Balmer series
. This is a unique event, because it occurs in a galaxy that is imaged almost constantly. It is expected to be observable for northern hemisphere observers for several months.
This is the third supernova to be recorded in the Whirlpool galaxy in 17 years (following SN 1994I
and SN 2005cs
) which is a lot for a single galaxy. The galactic supernova frequency is estimated to be around one event every 40 years.
magnitude of 6.5. The supernova is an easy target for an amateur telescope equipped with a modern CCD camera
under a dark sky.
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
in the Whirlpool Galaxy
Whirlpool Galaxy
The Whirlpool Galaxy is an interacting grand-design spiral galaxy that is estimated to be 23 ± 4 million light-years from the Milky Way Galaxy. in the constellation Canes Venatici...
(M51). On 31 May 2011 an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
13.5 type II supernova
Type II supernova
A Type II supernova results from the rapid collapse and violent explosion of a massive star. A star must have at least 9 times, and no more than 40–50 times the mass of the Sun for this type of explosion. It is distinguished from other types of supernova by the presence of hydrogen in its spectrum...
(the explosion of a single massive star) was detected in M51 at coordinates 13:30:05.08 +47:10:11.2. It was discovered by Amédée Riou and confirmed by several sources, including the Palomar Transient Factory
Palomar Transient Factory
The Palomar Transient Factory is an astronomical wide-field survey designed to search for optical transient and variable sources. It is fully automated, including a wide-field survey camera, an automated realtime data reduction pipeline, a dedicated photometric follow up telescope, and a full...
. A candidate progenitor has been detected in Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
images at coordinates 13:30:05.119 +47:10:11.55. The progenitor may have been a highly luminous yellow supergiant
Yellow supergiant
A yellow supergiant is a supergiant star of spectral type F or G. These stars usually have masses between 15 and 20 solar masses. These stars, like any other supergiant,...
with an initial mass of 18-24 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es. The supernova appears to have peaked near apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
12.1 on 19 June 2011.
Emission spectra
Emission spectrum
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted by the element's atoms or the compound's molecules when they are returned to a lower energy state....
from W. M. Keck Observatory, obtained by Palomar Transient Factory indicate that this is a type II supernova
Type II supernova
A Type II supernova results from the rapid collapse and violent explosion of a massive star. A star must have at least 9 times, and no more than 40–50 times the mass of the Sun for this type of explosion. It is distinguished from other types of supernova by the presence of hydrogen in its spectrum...
with a relatively blue continuum with P Cygni
P Cygni
P Cygni is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in Uranometria as a nova....
profiles in the Balmer series
Balmer series
The Balmer series or Balmer lines in atomic physics, is the designation of one of a set of six different named series describing the spectral line emissions of the hydrogen atom....
. This is a unique event, because it occurs in a galaxy that is imaged almost constantly. It is expected to be observable for northern hemisphere observers for several months.
This is the third supernova to be recorded in the Whirlpool galaxy in 17 years (following SN 1994I
SN 1994I
SN 1994I is a Type Ic supernova discovered on April 2, 1994 in the Whirlpool Galaxy by amateur astronomers Tim Puckett and Jerry Armstrong of the Atlanta Astronomy Club. Type Ic supernova are a rare type of supernova that result from the explosion of a very massive star that has shed its outer...
and SN 2005cs
SN 2005cs
SN 2005cs was a supernova in the Whirlpool Galaxy. It was a type II supernova, discovered by a German amateur astronomer....
) which is a lot for a single galaxy. The galactic supernova frequency is estimated to be around one event every 40 years.
Observing
In terms of visual stargazing with a large amateur telescope, this object may not jump out at the viewer. As of June 25, it may be holding reasonably steady at magnitude 12.7. The supernova is about 300 times fainter than the naked eyeNaked eye
The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...
magnitude of 6.5. The supernova is an easy target for an amateur telescope equipped with a modern CCD camera
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
under a dark sky.
External links
- GIF animation of pre and post images of SN 2011dh
- Views of the developing supernova
- SN 2011dh progenitor?
- Magnitude comparison 2011-06-02
- Twitter Helps Astronomers Zero-In on M51 Supernova (Jun 6, 2011 Ian O'Neill)
- M51 (Whirlpool Galaxy) at Las Cumbres Observatory on 6 Jun 2011
- Supernova sn2011dh in M51 is brightening! (June 14, 2011 Ian Musgrave)
- PTF11eon/SN2011dh: Discovery of a Type IIb Supernova From a Compact Progenitor in the Nearby Galaxy M51 (arXiv:1106.3551 : 17 Jun 2011)
- Panchromatic Observations of SN 2011dh Point to a Compact Progenitor Star (arXiv:1107.1876 : 10 Jul 2011)
